EMC4002 (Microchip)
SMBus Fan Driver

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EMC4002
SMBus Fan Driver with Temperature Monitoring
PRODUCT FEATURES
Description
The EMC4002 is a combination fan controller device,
temperature sensor, and thermal monitor. It contains two
RPM based Fan Control Algorithms that monitor the
fan’s speed and automatically adjust the drive to
maintain the desired fan speed. These RPM based Fan
Control Algorithms act independently and can be
coupled to either a Dual Voltage High Side Fan driver or
a PWM output. The Dual Voltage High Side fan drivers
offer power savings by only drawing current from the
necessary supply line based on the output voltage
settings.
In addition, the EMC4002 monitors up to nine (9)
external diode or thermistor channels and up to seven
(7) voltage channels.
The EMC4002 also acts as an always on thermal
monitor to signal a system wide interrupt should the
CPU well temperature exceed a hardware set limit that
cannot be altered via software. This ThermTrip logic
uses signals from other external devices to determine
overall system operation.
Finally, the EMC4002 contains a programmable Low
Dropout Voltage Regulator to supply 3.3V, 2.5V, or a
user selected voltage. This LDO is muxed with one of
the two Dual Voltage High Side Fan Drivers for flexibility.
Each can source up to 600mA of current from the
VDD_5V supply.
Features
RPM Closed-loop Control
— “Set and Forget control”
— 1% control accuracy with external clock
— Two 10 Bit PWMs
— Two 10 bit TACHs
BC-LinkTM Communications Interface
— Up to 24Mbps data rate
— Multiplexed with SMBus
Data Sheet
Flexible Thermal Monitors
— Anti-Parallel Diodes allow 2 thermal diodes on one
DP/DN pair
— Two DP and DN pins may also be used as voltage
inputs to monitor thermistors or voltages
Voltage Regulator Multiplexed with Dual Voltage Fan
Driver
— LDO: 3.3V in, 600mA @ 2.5V out, or 5V in, 400mA @
3.3V out
— Dual Voltage Fan Driver rated 600mA @ 5V
Vset uses a single 1% resistor
Voltage Programmable Fail-Safe Monitor
— External voltage programmed thermal sensor
— Can use either a remote diode or thermistor
ThermTrip Logic Integration
Dual Voltage Fan Driver
— Uses 5V or 3.3V supply for power efficiency
— 600mA maximum output current drive
— 10 bit resolution
Up to Nine External Temperature Monitors
— ±1°C Accuracy 60°C to 100°C
— Resistance Error Correction
— Automatically detects and supports CPU diodes
requiring the BJT or Transistor models
Up to Seven Voltage Monitors
— Monitors VDD
— Programming Voltage (VSET)
— Vcp1, Vcp2, and a low (0.8V max) voltage input
— Two voltage inputs mux’d on diode lines
5 (mux’d) General Purpose Digital I/O’s
SMBus 2.0 Compliant interface
— Two selectable addresses
— SMBus Alert
48 pin QFN, RoHS Compliant package, 7x7mm with
exposed pad
2014 Microchip Technology Inc.
DS20005276A-page 1


EMC4002 (Microchip)
SMBus Fan Driver

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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Order Number:
EMC4002-HZH for 48-pin, RoHS Compliant package
This product meets the halogen maximum concentration values per IEC61249-2-21
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via
E-mail at docerrors@microchip.com. We welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for cur-
rent devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the
revision of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include -literature number) you are
using.
Customer Notification System
Register on our web site at www.microchip.com to receive the most current information on all of our products.
DS20005276A-page 2
2014 Microchip Technology Inc.


EMC4002 (Microchip)
SMBus Fan Driver

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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table of Contents
Chapter 1 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chapter 2 Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chapter 3 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3 SMBus Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.4 BC-Link Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter 4 Communications Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1 Selecting Communications Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.2 SMBus Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.2.1 SMBus Start Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.2 SMBus Address and RD / WR Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.3 SMBus Data Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.4 SMBus ACK and NACK Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2.5 SMBus Stop Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2.6 SMBus Time-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2.7 SMBus and I2C Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.3 SMBus Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.3.1 SMBus Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.3.2 SMBus Read Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.3.3 SMBus Send Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.3.4 SMBus Receive Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.3.5 SMBus Alert Response Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.4 BC-Link Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Chapter 5 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.1 General Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2 Conversion Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.3 Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.4 Fan Control Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.5 RPM Based Fan Control Algorithms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5.1 Programming the RPM based Fan Control Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.5.2 Tachometer Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5.3 Spin Up Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.5.4 32KHz Clock Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.6 Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
5.7 Dual Voltage Fan Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.7.1 Short Circuit Current Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.8 PWM Drivers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.9 Low Dropout Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.9.1 Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.9.2 Output Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.9.3 Power OK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.9.4 Short Circuit Condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.10 Thermal Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
5.11 Voltage Monitors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.11.1 Input Attenuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.11.2 VCPx as Thermistor Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2014 Microchip Technology Inc.
DS20005276A-page 3


EMC4002 (Microchip)
SMBus Fan Driver

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SMBus Fan Driver with Temperature Monitoring
Data Sheet
5.12
5.13
5.14
5.15
5.16
5.17
5.18
5.19
5.20
Temperature Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.12.1 Resistance Error Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.12.2 Beta Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Anti-Parallel Diode Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
ADC/Thermistor Support on External Diode Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Diode Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5.15.1 Anti-Parallel Diode Capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.15.2 Diode Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Voltage Programmable Fail-Safe Temperature Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.16.1 VSET Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.16.2 Internal POWER_OK Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.16.3 Internal HW_FAILSAFE# Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
ThermTrip Logic Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.17.1 POWER_SW# Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
5.17.2 ACAVAIL_CLR Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
General Purpose I/Os . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Alerts and Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Multiple Supply Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Chapter 6 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.1 Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.1.1 Lock Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.2 Data Read Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.2.1 Programming the Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.3 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.4 Voltage Data Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
6.5 GPIO Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.6 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.7 GPIO Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.8 GPIO Direction Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
6.9 GPIO Output Config Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
6.10 GPIO Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.11 GPIO Interrupt Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.12 Dual Voltage Fan Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.13 Dual Voltage Fan Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.14 Beta Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.15 Ideality Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.16 PWM Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.17 Company ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.18 Revision Register (3Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.19 Lock Start Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.20 Interrupt Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.20.1 Interrupt Status Register 1 (41h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
6.20.2 Interrupt Status Register 2 (42h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.20.3 Interrupt Status Register 3 (44h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.20.4 Interrupt Status Register 4 (45h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.21 ThermTrip Pin State Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.22 Voltage Limit Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
6.23 Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
6.24 REC Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.25 PWM Divide Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.26 ThermTrip Temperature Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.27 Failsafe Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.28 FailSafe Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.29 Error Debug Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
DS20005276A-page 4
2014 Microchip Technology Inc.


EMC4002 (Microchip)
SMBus Fan Driver

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SMBus Fan Driver with Temperature Monitoring
Data Sheet
6.30
6.31
6.32
6.33
6.34
6.35
6.36
6.37
6.38
6.39
6.40
6.41
6.42
6.43
Special Function Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Interrupt Status Enable Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.31.1 Interrupt Status Enable Register 2 (7Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.31.2 Interrupt Status Enable Register 1 (7Eh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6.31.3 Interrupt Status Enable Register 3 (7Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Fan Driver Setting Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Fan Configuration 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Fan Configuration 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Gain Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Fan Spin Up Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Fan Step Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Fan Minimum Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Valid TACH Count Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Fan Drive Fail Band Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Product ID Register (FDh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Chapter 7 Package Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Chapter 8 XOR Test Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
8.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
8.2 Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
8.3 Enabling/Disabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Appendix A Thermistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
A.1 Thermistor Look Up Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Appendix B RPM to Tachometer Count Look Up Tables . . . . . . . . . . . . . . . . . . . . . . . . . . 103
B.1 1k RPM Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Chapter 9 EMC4002 Data Sheet Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
2014 Microchip Technology Inc.
DS20005276A-page 5


EMC4002 (Microchip)
SMBus Fan Driver

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List of Figures
SMBus Fan Driver with Temperature Monitoring
Data Sheet
Figure 1.1 EMC4002 Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 2.1 Pin Diagram for EMC4002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 4.1 BC-Link Multiplexed with SMBus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 4.2 SMBus Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 4.3 LSBC Bus Interface Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 5.1 System Diagram for EMC4002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 5.2 RPM based Fan Control Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 5.3 Spin Up Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 5.4 Block Diagram of Low Dropout Voltage Regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 5.5 Adjustable LDO Output Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 5.6 Configurable Thermal Diode Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Figure 5.7 Diode Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 5.8 Anti-Parallel Diode Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 5.9 Vset Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Figure 5.10 Example #1 of HW_FAILSAFE# Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 5.11 Example #2 of HW_FAILSAFE# Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 5.12 Temperature Channel Interrupt Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 5.13 Other Channel Interrupt Flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 5.14 Power Supply Domains for EMC4002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Figure 6.1 Ramp Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Figure 7.1 48-Pin QFN 7mm x 7mm Package Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Figure A.1 “Low Side” Thermistor Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
DS20005276A-page 6
2014 Microchip Technology Inc.


EMC4002 (Microchip)
SMBus Fan Driver

No Preview Available !

Click to Download PDF File for PC

SMBus Fan Driver with Temperature Monitoring
Data Sheet
List of Tables
Table 2.1 Pin Functions for EMC4002. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 2.2 Pin Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 3.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 3.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 4.1 SMBus Address and Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 4.2 Protocol Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 4.3 Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 4.4 Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 4.5 Send Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 4.6 Receive Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 4.7 Alert Response Address Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 5.1 Conversion Channel Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 5.2 Power States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 5.3 Fan Controls Active for Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 5.4 LDO / Fan Driver Configuration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 5.5 Voltage Input Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 5.6 VSET Resistor Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 5.7 ThermTrip Logic Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Table 6.1 EMC4002 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Table 6.2 Temperature Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Table 6.3 Temperature Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Table 6.4 Voltage Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Table 6.5 Voltage Data Format Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Table 6.6 GPIO Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Table 6.7 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Table 6.8 Temp Conversion Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Table 6.9 GPIO Config Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Table 6.10 GPIO Config Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Table 6.11 GPIO Config Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Table 6.12 GPIO Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Table 6.13 GPIO Mask Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Table 6.14 Dual Voltage Fan Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Table 6.15 5V_EN and 3V_EN Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Table 6.16 Dual Voltage Fan Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Table 6.17 Beta Configuration Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Table 6.18 Beta Compensation Look Up Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 6.19 Ideality Configuration Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 6.20 Ideality Factor Look Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 6.21 PWM Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 6.22 PWMx_BASE[1:0] Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Table 6.23 Company ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Table 6.24 Revision Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Table 6.25 Lock Start Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Table 6.26 Interrupt Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Table 6.27 ThermTrip Pin State Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Table 6.28 Voltage Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Table 6.29 Temperature Limit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Table 6.30 REC Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Table 6.31 PWM Divide Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Table 6.32 ThermTrip Temperature Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 6.33 FailSafe Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 6.34 FailSafe Config Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Table 6.35 Error Debug Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
2014 Microchip Technology Inc.
DS20005276A-page 7


EMC4002 (Microchip)
SMBus Fan Driver

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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 6.36 Special Function Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Table 6.37 Interrupt Enable Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Table 6.38 Fan Driver Setting Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Table 6.39 Fan Configuration 1 Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Table 6.40 Range Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Table 6.41 Minimum Edges for Fan Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Table 6.42 Update Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Table 6.43 Fan Configuration 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Table 6.44 Derivative Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Table 6.45 Error Range Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Table 6.46 Gain Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Table 6.47 Gain Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Table 6.48 Fan TACH Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Table 6.49 DRIVE_FAIL_CNT[1:0] Bit Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 6.50 Spin Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Table 6.51 Spin Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Table 6.52 Fan Step Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Table 6.53 Minimum Fan Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Table 6.54 Valid TACH Count Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Table 6.55 Fan Drive Fail Band Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Table 6.56 TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Table 6.57 TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Table 6.58 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Table 7.1 48-Pin QFN 7mm x 7mm Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Table A.1 “Low Side” Thermistor Look Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Table A.2 Inverted Thermistor Look Up Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Table B.1 Tachometer Count to RPM Look Up Table (Range = 1000 RPM). . . . . . . . . . . . . . . . . . . . . 103
Table 9.1 Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
DS20005276A-page 8
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Chapter 1 Block Diagram
VDD
VSET
VIN1
DN1 / Therm
DP1 / VREF_T
DN2
DP2
DN3 / DP7
DP3 / DN7
DN4 / DP8
DP4 / DN8
DN5 / DP9
DP5 / DN9
DN6 / VIN2
DP6 / VREF_T2
External
Temp
Diodes
Internal
Temp
Analog
Mux
THERM_STP# Logic
Communications
Block
Voltage
Failsafe
Logic
11 bit Σ Δ
ADC
Voltage
Registers
Temp Registers
Register
Set and
Logic
SMCLK / BC-LINK CLK
SMDATA / BC-LINK DATA
ATF_INT# / BC-LINK IRQ#
3V_PWROK#
VDD_PWRGD
ADDR_MODE / XEN#
GPIOs
FAN 1
Driver and RPM
Control Logic
LDO / FAN 2
Driver and RPM
Control Logic
TACH
Measurement
Logic
* ASTERISK DENOTES MULTIPLE
PIN FUNCTIONS
Multiplexed GPIOs:
PWM2 / GPIO1
TACH1 / GPIO3
TACH2 / GPIO4
CLK_IN / GPIO2
THERMTRIP_SIO / PWM1 / GPIO5
Figure 1.1 EMC4002 Functional Block Diagram
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Chapter 2 Pin Configuration
SMBus Fan Driver with Temperature Monitoring
Data Sheet
DP6 / VREF_T2 1
DN6 / VIN2 2
ADDR_MODE / XEN 3
VDD 4
VDDH1
VDDH1
5
6
FAN_OUT1 7
FAN_OUT1 8
VDDL1 9
SMDATA / BC-LINK_DATA 10
SMCLK / BC-LINK_CLK 11
ATF_INT# / BC_LINK_IRQ# 12
EMC4002
7mm x 7mm
36 DP1 / VREF_T
35 DN1 / THERM
34 LDO_POK
33 LDO_SET
32 VDDH2
31 VDDH2
30 LDO_OUT / FAN_OUT2
29 LDO_OUT / FAN_OUT2
28 VDDL2
27 ACAVAIL_CLR
26 POWER_SW#
25 SYS_SHDN#
Figure 2.1 Pin Diagram for EMC4002
DS20005276A-page 10
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Data Sheet
Table 2.1 Pin Functions for EMC4002
PIN
NUMBER
1
2
3
4
5
6
7
NAME
FUNCTION
PIN TYPE
DP6 / VREF_T2
DP6 - External Diode 6 positive (anode)
connection
VREF_T2 - Switched reference output
DN6 / VIN2
DN6 - External Diode 6 negative
(cathode) connection
VIN2 - General ADC input 2
ADDR_MODE / XEN ADDR_MODE - Address mode selection
XEN - XOR Mode enable
VDD
Positive Supply Voltage for general
operation
VDDH1
5V supply for Dual Voltage Fan Driver
VDDH1
5V supply for Dual Voltage Fan Driver
FAN_OUT1
Fan output for Dual Voltage Fan Driver 1
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
DI (5V)
DI (5V)
Power
Power (5V)
Power (5V)
AO (5V)
8
FAN_OUT1
Fan output for Dual Voltage Fan Driver 1 AO (5V)
9
VDDL1
3.3V supply for Dual Voltage Fan Driver
Power
10
SMDATA / BC-
SMDATA - Bi-directional SMBus data
DIOD (5V)
LINK_DATA
line. Requires a pull up resistor
BC-LINK_DATA - Bi-directional BC-Link
Data line. Requires a pull-up resistor
DIOD (5V)
11 SMCLK / BC-
SMCLK - SMBus Clock line.
DI (5V)
LINK_CLK
BC-LINK_CLK - BC-LINK Clock line.
DI (5V)
12
ATF_INT# / BC-
ATF_INT# - Active low interrupt output
OD (5V)
LINK_IRQ#
for SMBus
BC-LINK_IRQ# - Active low interrupt
output for BC-LINK
OD (5V)
13
PWM2 / GPIO1
PWM2 - Open Drain PWM Output
OD (5V)
(software programmed)
PWM2 - Push - Pull PWM Output
(software programmed)
DO
GPI1 - General purpose input
(default)
DI (5V)
GPO1 - General purpose push-pull
output
(software programmed)
DO
GPO1 - General purpose open drain
output
(software programmed)
OD (5V)
POWER
PLANE
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDDH1
VDDH1
VDDH1 and
VDDL1
VDDH1 and
VDDL1
VDDL1
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
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PIN
NUMBER
14
15
16
17
18
19
SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 2.1 Pin Functions for EMC4002 (continued)
NAME
CLK_IN / GPIO2
TACH1 / GPIO3
TACH 2 / GPIO4
3V_PWROK#
VDD_PWRGD
LDO_SHDN#
FUNCTION
CLK_IN - 32.768kHz clock input for
TACH measurement
(default)
GPI2 - General purpose input
(software programmed)
GPO2 - General purpose push-pull
output
(software programmed)
GPO2 - General purpose open drain
output
(software programmed)
TACH1 - TACH input for fan controller 1
(default)
GPI3 - General purpose input
(software programmed)
GPO3 - General purpose push-pull
output
(software programmed)
GPO3 - General purpose open drain
output
(software programmed)
TACH2 - TACH input for fan controller 2
(software programmed)
GPI4 - General purpose input
(default)
GPO4 - General purpose push-pull
output
(software programmed)
GPO4 - General purpose open drain
output
(software programmed)
Active low power okay input
Active high power okay input
Active low shutdown for LDO
PIN TYPE
DI (5V)
DI (5V)
DO
OD (5V)
DI (5V)
DI (5V)
DO
OD (5V)
DI (5V)
DI (5V)
DO
OD (5V)
DI (5V)
DI (5V)
DI (5V)
POWER
PLANE
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
DS20005276A-page 12
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 2.1 Pin Functions for EMC4002 (continued)
PIN
NUMBER
20
21
22
23
24
25
26
27
28
29
30
31
32
33
NAME
THERMTRIP_SIO /
PWM1 / GPIO5
RTC_PWR3V
THERMTRIP1#
THERMTRIP2#
THERMTRIP3#
SYS_SHDN#
POWER_SW#
ACAVAIL_CLR
VDDL2
LDO_OUT /
FAN_OUT2
LDO_OUT /
FAN_OUT2
VDDH2
VDDH2
LDO_SET
FUNCTION
THERMTRIP_SIO - Open Drain, active
high output from ThermTrip Logic
(default)
PWM1 - Open Drain PWM driver output
PWM1 - Push-Pull PWM driver output
GPI5 - General purpose input
(software programmed)
GPO5 - General purpose push-pull
output
(software programmed)
GPO5 - General purpose open drain
output
(software programmed)
RTC power input
Active low thermtrip input
Active low thermtrip input
Active low thermtrip input
Active low output from ThermTrip Logic
Active low reset for ThermTrip logic
output
Active high reset for Thermtrip logic
output
VDDL2 - LDO supply
VDDL2 - Dual Voltage Fan Driver 2 3.3V
supply
LDO_OUT - LDO regulated output
FAN_OUT2 - Dual Voltage Fan Driver 2
Output
LDO_OUT - LDO regulated output
FAN_OUT2 - Dual Voltage Fan Driver 2
Output
VDDH2- LDO supply
VDDH2 - Dual Voltage Fan Driver 5V
supply
VDDH2 - LDO supply
VDDH2 - Dual Voltage Fan Driver 2 5V
supply
LDO output set input
PIN TYPE
OD (5V)
OD (5V)
DO
DI (5V)
DO
OD (5V)
Power
DI (5V)
DI (5V)
DI (5V)
OD (5V)
DI (5V)
DI (5V)
Power
Power
AO (5V)
AO (5V)
AO (5V)
AO (5V)
Power
Power
Power
Power
AIO
POWER
PLANE
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
RTC_PWR3V
VDDL2
VDDL2
VDDL2 and
VDDH2
VDDL2 and
VDDH2
VDDL2 and
VDDH2
VDDL2 and
VDDH2
VDDH2
VDDH2
VDDH2
VDDH2
VDDH2
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PIN
NUMBER
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Exposed
Bottom Pad
SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 2.1 Pin Functions for EMC4002 (continued)
NAME
LDO_POK
DN1 / THERM
DP1 / VREF_T
DN2
DP2
VIN1
DN3 / DP7
DP3 / DN7
VSET
DN4 / DP8
DP4 / DN8
VCP2
DN5 / DP9
DP5 / DN9
VCP1
VSS
FUNCTION
Power Ok output signal for LDO
DN1 - External Diode 1 negative
(cathode) connection
THERM - Thermistor measurement
input
DP1 - External Diode 1 positive (anode)
connection
VREF_T - Thermistor measurement
reference voltage
External Diode 2 negative (cathode)
connection
External Diode 2 positive (anode)
connection
General Voltage Input
External Diode 3 negative (cathode)
connection and External Diode 7
positive (anode) connection when APD
enabled
External Diode 3 positive (anode)
connection and External Diode 7
negative (cathode) connection when
APD enabled
Voltage input to set hardware failsafe
temperature threshold
External Diode 4 negative (cathode)
connection and External Diode 8
positive (anode) connection when APD
enabled
External Diode 4 positive (anode)
connection and External Diode 8
negative (cathode) connection when
APD enabled
Voltage Input for VCP2 channel
External Diode 5 negative (cathode)
connection and External Diode 9
positive (anode) connection when APD
enabled
External Diode 5 positive (anode)
connection and External Diode 9
negative (cathode) connection when
APD enabled
Voltage Input for VCP1 channel
Ground Connection
PIN TYPE
OD (5V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO (2V)
AIO
AIO (2V)
AIO (2V)
AIO
Power
POWER
PLANE
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
VDD
DS20005276A-page 14
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
The EMC4002 is available in a 48 pin 7mm x 7mm QFN package with exposed pad. The Exposed
bottom pad must be electrically connected to ground for proper operation and thermal protection.
All pins labelled (5V) are 5V tolerant. All pins labelled (2V) are 2V tolerant.
The pin type is shown in Table 2.2.
PIN TYPE
Power
DI
AIO
AO
DO
DIOD
OD
Table 2.2 Pin Types
DESCRIPTION
This pin is used to supply power or ground to the device.
Digital Input - this pin is used as a digital input. This pin is
5V tolerant.
Analog Input / Output - this pin is used as an I/O for analog
signals.
Analog Output - this pin is used for outputting analog
signals and amy have large current sourcing capabilities
Push / Pull Digital Output - this pin is used as a digital
output. It can both source and sink current.
Digital Input / Open Drain Output this pin is used as an
digital I/O. When it is used as an output, It is open drain
and requires a pull-up resistor. This pin is 5V tolerant.
Open Drain Digital Output - this pin is used as a digital
output. It is open drain and requires a pull-up resistor. This
pin is 5V tolerant.
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DS20005276A-page 15


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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Chapter 3 Electrical Specifications
3.1 Absolute Maximum Ratings
Table 3.1 Absolute Maximum Ratings
DESCRIPTION
Note 3.1
Voltage on VDD pin
Voltage on RTC_PWR3V pin
Voltage on 5V tolerant pins
Voltage on LDO_OUT pin
Voltage on FAN_OUT pin
Voltage on SYS_SHDN# and
THERMTRIP_SIO pins
Voltage on 2V tolerant pins
Voltage on any other pin to GND
Operating Ambient Temperature Range
Operating Die Temperature Range
Storage Temperature Range
Package Power Dissipation Note 3.2
Power Derating
Junction to Ambient (θJA) Note 3.3
ESD Rating, All pins HBM
RATING
4V
4V
-0.3 to 6.5
-0.3 to VDDH2 or VDDL2+ 0.3
-0.3 to VDDH1 + 0.3 or VDDH2 + 0.3
-0.3 to RTC_PWR3V + 0.3
-0.3 to 2.6
-0.3 to VDD + 0.3
0 to 85
0 to 125
-55 to 150
1.2W up to TA = 85°C
44, TA > 85°C
20-52
2000
UNIT
V
V
V
V
V
V
V
V
°C
°C
°C
W
mW /°C
°C/W
V
Note:
Stresses above those listed could cause permanent damage to the device. This is a stress
rating only and functional operation of the device at any other condition above those indicated
in the operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Note 3.1 All voltages are relative to ground.
Note 3.2 The Package Power Dissipation specification assumes a thermal via design consisting of
nine 20mil vias connected to the ground plane with a 4x4mm thermal landing.
Note 3.3
Junction to Ambient (θJA) is dependent on the design of the thermal vias. Without thermal
vias and a thermal landing, the θJA is approximately 52°C/W including localized PCB
temperature increase. Refer to Application Note “Power and Layout Considerations for
EMC4002” for design guidance to implement the thermal via and landing solution.
DS20005276A-page 16
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
3.2 Electrical Specifications
Table 3.2 Electrical Specifications
VDD = 3V to 3.6V, RTC_PWR3V = 2V to 3.6V, VDDL2 = VDDH2 = 3V to 5.5V, VDDL1 = 3.3V to 3.6V, VDDH1 = 4.5V to 5.5V, TA = 0°C to 85°C
All Typical values at VDD = 3.3V, RTC_PWR3V = 3.3V, VDDH2 = VDDL2 = 3.3V, VDDH1 = 5V, VDDL1 = 3.3V, TA = 27°C unless otherwise
noted.
CHARACTERISTIC SYMBOL MIN
TYP MAX UNIT
CONDITIONS
Supply Voltage (VDD)
VDD
RTC Supply Voltage
RTC_PWR
3V
RTC Data Retention
Supply Current from
VDD pin
ISUS
Supply current from
RTC_PWR3V pin
IRTC
Sleep Current from
VDD
ISLEEP
Low Power Current
from VDD
ILPM
POR Threshold
Temperature
Accuracy
VPORR
VPORF
Temperature
Resolution
Conversion Time per
Channel
Diode decoupling
capacitor
Resistance Error
Corrected
tCONV
tCONV
CFILTER
RSERIES
Voltage Measurement
Accuracy
VTHERM
DC Power
3 3.3 3.6 V
2
3.3 3.6
V
2V
1.5 2 mA
5 uA
700 uA
900 uA
2.2 V
2V
External Temperature Monitors
±0.5 ±1 °C
±1 ±2 °C
0.125
°C
Continuous Conversions, Fan
Drivers enabled at max
frequency (PWM)
Monitoring Disabled, Fan
Drivers Disabled, LDO disabled,
VDD disabled.
Fan drivers disabled, Monitoring
disabled (3V_PWROK# or
VSUS_PWRGD unasserted)
Fan drivers disabled.
3V_PWROK# or
VSUS_PWRGD unasserted.
LPM bit set. Continuous
Conversions
Rising edge of VDD or
RTC_PWR3V
Falling edge of VDD
60°C < TDIODE < 100°C, 30°C <
Tdie < 85°C Note 3.4
0°C < TDIODE < 125°C, 0°C <
Tdie < 115°C Note 3.4
43
22
2200
2700
100
Thermistor Monitors
0.5 1
ms
ms
pF
Ohm
External Diodes 1 - 3
External Diodes 4 - 9
Connected across external
diode
Total series resistance in DP
and DN lines
% 20°C < TTHERM < 80°C
1%, 10k Thermistor connected
to ground
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 3.2 Electrical Specifications (continued)
VDD = 3V to 3.6V, RTC_PWR3V = 2V to 3.6V, VDDL2 = VDDH2 = 3V to 5.5V, VDDL1 = 3.3V to 3.6V, VDDH1 = 4.5V to 5.5V, TA = 0°C to 85°C
All Typical values at VDD = 3.3V, RTC_PWR3V = 3.3V, VDDH2 = VDDL2 = 3.3V, VDDH1 = 5V, VDDL1 = 3.3V, TA = 27°C unless otherwise
noted.
CHARACTERISTIC SYMBOL MIN
TYP MAX UNIT
CONDITIONS
Temperature
Accuracy
TTHERM
Total Unadjusted
Error
Differential Non-
Linearity
Input Impedance
TUE
DNL
RIN
Conversion Time Per
Channel
tCONV
PWM Resolution
PWM Duty Cycle
PWM
DUTY
Tachometer Range
Tachometer Setting
Accuracy
TACH
ΔTACH
ΔTACH
Supply current from
VDDH pin
Supply current from
VDDL pin
Output High Voltage
from 5V supply
Sourcing Current
DC Short Circuit
Current Limit
Short circuit delay
Output Capacitive
Load
IDD5
IDD3
VOH_5V
ISOURCE
ISHORT
tDFS
CLOAD
12
Voltage Monitors
1
°C 20°C < TTHERM < 80°C
1%, 10k Thermistor connected
to ground (Note 3.5), 1% resistor
from VREF to VIN
% Measured at 3/4 full scale
±0.5 LSB
232 300
12.25
kOhm Impedance for those inputs with
input attenuators (VCP1, VCP2,
VDD)
ms
PWM Driver
1024
Steps
0 100 %
RPM Based Fan Controller
480 16000 RPM
±1 ±2 %
±2.5 ±5
%
Dual Voltage Fan Driver
35
uA
External oscillator 32.768kHz
Internal Oscillator
40°C < TDIE < 100°C
Fan not being driven
140 uA Fan not being driven
VDDH VDDH
- 0.3
- 0.4
V ISOURCE = 600mA, VDDH = 5V
600 mA
700 mA Sourcing current, Thermal
shutdown not triggered,
FAN_OUT = 0V
2 s See Section 5.7.1
10 100 uF 100mΩ < ESR < 1Ω
DS20005276A-page 18
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 3.2 Electrical Specifications (continued)
VDD = 3V to 3.6V, RTC_PWR3V = 2V to 3.6V, VDDL2 = VDDH2 = 3V to 5.5V, VDDL1 = 3.3V to 3.6V, VDDH1 = 4.5V to 5.5V, TA = 0°C to 85°C
All Typical values at VDD = 3.3V, RTC_PWR3V = 3.3V, VDDH2 = VDDL2 = 3.3V, VDDH1 = 5V, VDDL1 = 3.3V, TA = 27°C unless otherwise
noted.
CHARACTERISTIC SYMBOL MIN
TYP MAX UNIT
CONDITIONS
LDO Input Voltage
LDO Output Voltage
LDO Quiescent
Current
LDO Output Current
Regulated Output
Voltage Accuracy
Line Regulation
Load Regulation
Short Circuit Current
Output Capacitive
Load requirement
POK Range relative
to nominal LDO
output Voltage
POK Delay
Thermal Shutdown
Threshold
Thermal Shutdown
Hysteresis
Input High Voltage
Input Low Voltage
Output High Voltage
VLDO_IN
VLDO_OUT
ILDO
Low Dropout Regulator
3.0 3.3 3.6 V LDO_SET = Ground
4.5 5 5.5 V LDO_SET = 3.3V
2.5 V LDO_SET = Ground
3.3 V LDO_SET = VDD
1.12 2.5 V LDO_SET = resistor divider
140 uA ILOAD =0A, VDDH2 = VDDL2
ILOAD
ILOAD
ΔVLDO_OUT
0
0
600 mA LDO_OUT = 2.5V
400 mA LDO_OUT = 3.3V
1 2 % ILOAD = 600mA
ΔVLNR 0.5 % ILOAD = 600mA, VLDO_IN = 3.0V
to 3.6V
ΔVLDR 0.5 % ILOAD = 0A to 600mA
ISHORT
700 1000 mA VLDO_OUT = 0V
CLOAD
10
100 uF 100mΩ < ESR < 1Ω
VOK
tDPOK
TSDTH
80 82.5 85
75 82.5 90
42 55 77
Thermal Shutdown
150
% LDO_SET = ground or +3.3V
Compared to VLDO_OUT
% LDO_SET = resistor divider
Compared to VLDO_OUT
us Delay after LDO output drops
below the trip level.
°C
TSDHYST
50
°C
Digital I/O, ALERT#, and LDO_POK pins
VIH
VIL
VOH
2.0
VDD -
0.4
V
0.8 V
V 4mA current drive
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
Table 3.2 Electrical Specifications (continued)
VDD = 3V to 3.6V, RTC_PWR3V = 2V to 3.6V, VDDL2 = VDDH2 = 3V to 5.5V, VDDL1 = 3.3V to 3.6V, VDDH1 = 4.5V to 5.5V, TA = 0°C to 85°C
All Typical values at VDD = 3.3V, RTC_PWR3V = 3.3V, VDDH2 = VDDL2 = 3.3V, VDDH1 = 5V, VDDL1 = 3.3V, TA = 27°C unless otherwise
noted.
CHARACTERISTIC SYMBOL MIN
TYP MAX UNIT
CONDITIONS
Output Low Voltage
Leakage Current
VOL
ILEAK
0.4 V 4mA current sink
±5 uA ALERT#, SYS_SHDN#,
THERMTRIP_SIO pins
Device powered or unpowered
Note 3.4
Note 3.5
TDIE refers to the internal die temperature and may not match TA due to self heating of
the device. The internal temperature sensor will return TDIE.
The EMC4002 performs no calculations to determine the thermistor temperature. These
specifications are based on the thermistor data shown in Table A.1, "“Low Side” Thermistor
Look Up Table" and are not guaranteed.
3.3 SMBus Electrical Characteristics
VDD = 3V to 3.6V, TA = 0°C to 85°C, Typical values are at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL MIN TYP MAX UNITS
CONDITIONS
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
Input High/Low Current
Hysteresis
Input Capacitance
Clock Frequency
Spike Suppression
Bus free time Start to
Stop
Setup Time: Start
Setup Time: Stop
Data Hold Time
Data Setup Time
Clock Low Period
VIH
VIL
VOH
VOL
IIH / IIL
CIN
fSMB
tSP
tBUF
SMBus Interface
2.0 V
0.8 V
VDD
- 0.4
V
0.4 V
±5 uA
420 mV
SMBus Timing
5 pF
10 400 kHz
50 ns
1.3 us
SMCLK
SMCLK
24mA current drive - SMDATA
24mA current sink - SMDATA
Device Powered or Unpowered
tSU:STA
tSU:STP
tHD:DAT
tSU:DAT
tLOW
0.6
0.6
0.6
0.6
1.3
us
us
6 us
72 us
us
DS20005276A-page 20
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Data Sheet
VDD = 3V to 3.6V, TA = 0°C to 85°C, Typical values are at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL MIN TYP MAX UNITS
CONDITIONS
Clock High Period
Clock/Data Fall time
Clock/Data Rise time
Capacitive Load
tHIGH
tFALL
tRISE
CLOAD
0.6
us
300 ns Min = 20+0.1CLOAD ns
300 ns Min = 20+0.1CLOAD ns
400 pF per bus line
3.4 BC-Link Electrical Characteristics
VDD = 3V to 3.6V, TA = 0°C to 85°C, Typical values are at TA = 27°C unless otherwise noted.
CHARACTERISTIC
SYMBOL MIN TYP MAX UNITS
CONDITIONS
Input High Voltage
Input Low Voltage
Output High Voltage
Output Low Voltage
Input High/Low Current
Hysteresis
Input Capacitance
Clock Period
Data Hold Time
Data Setup Time
Clock Duty Cycle
VIH
VIL
VOH
VOL
IIH / IIL
CIN
tCLK
tHD:DAT
tSU:DAT
Duty
Electrical Interface
2.0 V
0.8 V
VDD
- 0.4
V
0.4 V
-1 1 uA
420 mV
5 pF
Timing
34.7 41.6 52.1
7
ns
0 us
30 us
40 50
60
%
BC-LINK_CLK and BC-LINK_DAT
BC-LINK_CLK and BC-LINK_DAT
24mA current drive - BC-LINK_DAT
24mA current sink - BC-LINK_DAT
Data must be valid before clock
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Data Sheet
Chapter 4 Communications Protocols
The EMC4002 communicates with a host controller, such as a Microchip KBC using one of two
communications protocols that are automatically detected upon every communication. The two
protocols supported are the System Management Bus (SMBus) and the proprietary communications
protocol called BC-Link.
APPLICATION NOTE: No communications should be sent during the first 15ms after power up.
4.1
Selecting Communications Bus
The selection of the communications bus is performed automatically for each transaction. Once a
communication begins, the communication type is fixed until the communication ends.
After the communication ends, the device will wait 50ms before it resets the automatic detection
circuitry. Therefore, any communications received during this window will be assumed to be using the
protocol that was previously detected.
BC-Link Clock
BC-Link Data
BC-Link IRQ#
SMCLK
SMDATA
ALERT#
Bus
Select
(auto)
EMC4002
BC-Link
Interface
SMBus
Interface
Logic and
Registers
4.2
Figure 4.1 BC-Link Multiplexed with SMBus
SMBus Communications
The SMBus is a two-wire serial communication protocol between a computer host and its peripheral
devices. A detailed timing diagram is shown in Figure 4.2, "SMBus Timing Diagram". Stretching of the
SMCLK signal is supported, however the EMC4002 will not stretch the clock signal.
DS20005276A-page 22
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Data Sheet
.
SMCLK
TLOW
THIGH
TRISE
TFALL
THD:STA
TSU:STO
THD:STA
THD:DAT
TSU:DAT
TSU:STA
SMDATA
TBUF
P S S - Start Condition
S
Figure 4.2 SMBus Timing Diagram
P - Stop Condition P
4.2.1
4.2.2
SMBus Start Bit
The SMBus Start bit is defined as a transition of the SMBus Data line from a logic ‘1’ state to a logic
‘0’ state while the SMBus Clock line is in a logic ‘1’ state. When the EMC4002 detects an SMBus Start
bit, it will disable the BC-Link protocol circuitry and communicate using the SMBus Protocol
SMBus Address and RD / WR Bit
The SMBus Address Byte consists of the 7-bit client address followed by a -bit RD / WR indicator. If
this RD / WR bit is a logic ‘0’, then the SMBus Host is writing data to the client device. If this RD / WR
bit is a logic ‘1’, then the SMBus Host is reading data from the client device.
The EMC4002 can be used with two 7 bit client addresses. These addresses are chosen by the value
of the pull-up resistor on the ADDR_MODE/XEN pin upon power up. This pin also selects the mode
for Remote Diode #1, which can be either a diode or a thermistor. Table 4.1, "SMBus Address and
Mode Selection" summarizes the mode and address selections.
Table 4.1 SMBus Address and Mode Selection
RPULLUP ON ADDR_MODE/XEN PIN
<= 4.7k Ohm ±5%
10K Ohm ±5%
18K Ohm ±5%
>= 33k Ohm ±5%
REMOTE1 MODE
2N3904
2N3904
Thermistor
Thermistor
SMBUS ADDRESS
0101 111(r/w)b
0101 110(r/w)b
0101 111(r/w)b
0101 110(r/w)b
4.2.3
Attempting to communicate with the EMC4002 SMBus interface with an invalid client address or invalid
protocol will result in no response from the device and will not affect its register contents.
SMBus Data Bytes
All SMBus Data bytes are sent MSBit first and composed of 8-bits of information.
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4.2.4
4.2.5
4.2.6
4.2.7
SMBus ACK and NACK Bits
SMBus Fan Driver with Temperature Monitoring
Data Sheet
The SMBus client will acknowledge all data bytes that it receives (as well as the client address if it
matches and the ARA address if the ATF_INT# pin is asserted). This is done by the client device
pulling the SMBus Data line low after the 8th bit of each byte that is transmitted.
The Host will NACK (not acknowledge) the data received from the client by holding the SMBus data
line high after the 8th data bit has been sent.
SMBus Stop Bit
The SMBus Stop bit is defined as a transition of the SMBus Data line from a logic ‘0’ state to a logic
‘1’ state while the SMBus clock line is in a logic ‘1’ state. When the EMC4002 detects an SMBus Stop
bit, and it has been communicating with the SMBus protocol, it will reset its client interface and prepare
to receive further communications.
SMBus Time-out
The EMC4002 includes an SMBus time-out feature. Following a 30ms period of inactivity on the
SMBus, the device will time-out and reset the SMBus interface.
SMBus and I2C Compliance
The major difference between SMBus and I2C devices is highlighted here. For complete compliance
information refer to the SMBus 2.0 specification.
1. Minimum frequency for SMBus communications is 10kHz.
2. The client protocol will reset if the clock is held for longer than 30ms.
3. I2C devices do not support the Alert Response Address functionality (which is optional for SMBus).
4.3
SMBus Protocols
The EMC4002 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte and Write
Byte as valid protocols as shown below. It will respond to the Alert Response Address protocol but is
not in full compliance.
All of the below protocols use the convention in Table 4.2.
4.3.1
Table 4.2 Protocol Format
DATA SENT
TO DEVICE
Data sent
DATA SENT TO
THE HOST
Data sent
SMBus Write Byte
The Write Byte is used to write one byte of data to the registers as shown below Table 4.3:
START
0 ->1
CLIENT
ADDRESS
0101_110
DS20005276A-page 24
WR
0
Table 4.3 Write Byte Protocol
ACK
0
REGISTER
ADDRESS
XXh
ACK
0
REGISTER
DATA
XXh
ACK
0
STOP
1 -> 0
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4.3.2 SMBus Read Byte
The Read Byte protocol is used to read one byte of data from the registers as shown in Table 4.4.
Table 4.4 Read Byte Protocol
START
Client
ADDRESS
WR ACK
Register
Address
0->1 0101_110 0 0
XXh
ACK START
Client
Address
RD ACK Register NACK STOP
Data
0 0 ->1 0101_110 1 0 XXh 1 1 -> 0
4.3.3
SMBus Send Byte
The Send Byte protocol is used to set the internal address register pointer to the correct address
location. No data is transferred during the Send Byte protocol as shown in Table 4.5.
START
0 -> 1
CLIENT
ADDRESS
0101_110
Table 4.5 Send Byte Protocol
REGISTER
WR ACK ADDRESS
00
XXh
ACK
0
STOP
1 -> 0
4.3.4
SMBus Receive Byte
The Receive Byte protocol is used to read data from a register when the internal register address
pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads
of the same register as shown in Table 4.6.
START
0 -> 1
CLIENT
ADDRESS
0101_110
Table 4.6 Receive Byte Protocol
RD
ACK
REGISTER DATA
NACK
0b 0b
XXh
1
STOP
1 -> 0
4.3.5 SMBus Alert Response Address
The ATF_INT# output can be used as a processor interrupt or as an SMBALERT.
When it detects that the SMBALERT pin is asserted, the host will send the Alert Response Address
(general address of 000_1100b) on the bus. All devices with active interrupts will respond with their
client address as shown in Table 4.7.
..
Table 4.7 Alert Response Address Protocol
START
0 -> 1
ALERT
RESPONSE
ADDRESS
000_1100
DEVICE
RD
ACK
ADDRESS
NACK
STOP
1b 0b 0101_110x 1 1 -> 0
The EMC4002 will respond to the ARA command and will immediately de-assert the ATF_INT# pin by
clearing the INTEN bit (see Section 6.30).
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4.4
BC-Link Interface
SMBus Fan Driver with Temperature Monitoring
Data Sheet
The BC-Link is a proprietary bus developed to allow communication between a host controller based
device to a companion device. This device uses this serial bus to read and write registers and for
interrupt processing. The interface uses a data port concept, where the base interface has an address
register, data register and a control register, defined in the Microchip’s 8051’s SFR space.
Refer to documentation for the 8051 based host controller for details on how to access the EMC4002
via the BC-Link Interface.
8051
based
controller
(i.e.MEC5004)
BC-LINK_CLK
BC-LINK_DAT
BC-LINK_IRQ#
EMC4002
Figure 4.3 LSBC Bus Interface Signal Connections
DS20005276A-page 26
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Data Sheet
Chapter 5 Functional Description
5.1
General Operation
The EMC4002 is a combination fan controller device, temperature sensor, and thermal monitor. It
contains two RPM based Fan Control Algorithms that monitor the fan’s speed and automatically adjust
the drive to maintain the desired fan speed. These RPM based Fan Control Algorithms act
independently and can be coupled to either a Dual Voltage High Side Fan driver or a PWM output.
The Dual Voltage High Side fan drivers offer power savings by only drawing current from the necessary
supply line based on the output voltage settings.
In addition, the EMC4002 monitors up to nine (9) external diode or thermistor channels and up to
seven (7) voltage channels.
The EMC4002 also acts as an always on thermal monitor to signal a system wide interrupt should the
CPU temperature exceed a hardware set limit that cannot be altered via software. This ThermTrip logic
uses signals from other external devices to determine overall system operation.
Finally, the EMC4002 contains a programmable Low Dropout Voltage Regulator to supply 3.3V, 2.5V,
or a user selected voltage. This LDO is muxed with one of the two Dual Voltage High Side Fan Drivers
for flexibility. Each can source up to 600mA of current from the 5V supply or 300mA from the 3.3V
supply.
A system level diagram is shown in Figure 5.1.
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Data Sheet
VDDL = 3.3V
VDD = 3.3V
Keyboard Controller
(KBC)
BSC_DAT
BSC_CLK
IRQ
6.8k to 22k
+/- 5%
VDD VDDL2 VDDH 2
SMDATA / BC-LINK_DATA
SMCLK / BC-LINK_CLK
ATF_INT# / BC-LINK_IRQ#
ADDR_SEL / XEN#
3V_PWROK#
VDD_PWRGD
2.2nF as close to
pins as possible
DP1 / VREF_T1
LDO_OUT / FAN2_OUT
LDO_SET
10uF
LDO_SET connected to GND
0.1uF for 2.5V out, or connect external
divider for variable output
voltage
R1 = R2 * ((VOUT / 1.12) - 1)
R1 10uF 0.1uF
LDO_IN
~25k
R2
DN1 / THERM
2.2nF as close to
pins as possible
DP2
LDO_SHDN#
LDO_POK / FAN_SEL#
Anti-parallel
Diode
(optional)
2.2nF as close to
pins as possible
2.2nF as close to
pins as possible
Anti-parallel
Diode
(optional)
Anti-parallel
Diode
(optional)
RTC Power =
3.3V
2.2nF as close to
pins as possible
2.2nF as close to
pins as possible
3V_ALW
KBC
GPIO
DN2
DP3 / DN7
DN3 / DP7
DP4 / DN8
DN4 / DP8
DP5 / DN9
DN5 / DP9
VIN1
RTC_PWR3V
SYS_SHDN#
ACAVAIL_CLR
POWER_SW#
THERMTRIP1#
THERMTRIP2#
THERMTRIP3#
THERMTRIP_SIO /
PWM1 / GPIO5
VDDH1
FAN_OUT
TACH1 / GPIO3
VDDL1
Fan 1
10uF
0.1uF
100uF
0.1uF
CLK_IN/ GPIO2
PWM2 / GPIO1
TACH2 / GPIO4
vref
x1
Precision
Resistor
VCP1
VCP2
VSET
10uF
32.768kHz clock
Driver
Power
Monitor
Input
Power
Monitor
Input
Fan 2
Thermistor
Drive
DP6 / VREF_T2
vref x1
DN6 /VIN2
External
Diode
-OR-
Thermistor
Figure 5.1 System Diagram for EMC4002
DS20005276A-page 28
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SMBus Fan Driver with Temperature Monitoring
Data Sheet
5.2 Conversion Cycle
The EMC4002 monitors at least six (6) temperature channels (not including internal diode) and as
many as nine (9) in addition to at least five (5) voltage channels and as many as seven (7). All of these
measurements are performed in a round-robin loop. Whenever the EMC4002 monitoring is disabled
(by de-asserting either the 3V_PWROK# or the VDD_PWRGD signals) and restarted, the cycle starts
from the beginning.
ORDER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Table 5.1 Conversion Channel Order
CHANNEL
External Diode 1
Thermistor 1 (if enabled)
VSET Voltage
VDD Voltage
VCP1 Voltage
VCP2 Voltage
External Diode 2
External Diode 3
External Diode 7 (if enabled)
External Diode 4
External Diode 8 (if enabled)
External Diode 5
External Diode 9 (if enabled)
External Diode 6 (if enabled)
VIN2 (if enabled)
VIN1
Internal Diode
RESOLUTION
12-bit
10-bit
10-bit
10-bit
10-bit
10-bit
12-bit
12-bit
11-bit
11-bit
11-bit
11-bit
11-bit
11-bit
10-bit
10-bit
9-bit
5.3
Power Modes
The EMC4002 has several power modes depending on which functions are enabled. The Temperature
monitoring and Fan Drivers are each independently controlled. Typically, the device will only operate
in the Run Mode. However, if either the 3V_PWROK# or VDD_PWRGD signals become released
(either high or low respectively), then the other power modes are available.
Run Mode - in this mode, the EMC4002 continuously samples and updates all of its temperature
channels. The fan drivers are active and the RPM based Fan Control Algorithms are operating (if
enabled).
Low Power - In this mode, the EMC4002 is placed into a lower power mode. This mode is enabled
by setting the LPM bit and de-asserting either the VDD_PWRGD or the 3V_PWROK# signals. In
this mode the monitoring circuitry is still active and will sample and update all of its channels. The
SYS_SHDN# pin will be not be asserted for any reason. The Fan Drivers will be disabled but the
LDO will still be active unless disabled.
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Sleep - in this mode, the EMC4002 is placed into the lowest power mode available. This mode is
enabled by clearing the LPM bit (if set) and de-asserting either the VDD_PWRGD or the
3V_PWROK# signals to disable monitoring. The Fan Drivers will be disabled and the LDO will still
be active unless disabled. If disabled, then the device will be at its lowest power setting.
RTC Power Mode - this mode is reached by removing the VDD power supply. The device will not
function and cannot be communicated with in any way. The ThermTrip Logic will still be powered
though it cannot be updated.
APPLICATION NOTE: When in the RTC Power Mode, the THERMTRIP_SIO pin will be set to the default setting
of THERMTRIP_SIO.
Table 5.2 Power States
Run
Mode
Low
Power
Sleep
RTC
Power
Active
Active
Not
Active
Not
Active
Active User
Active
Defined
Not User Active
Active Defined
Not User Active
Active Defined
Not Not
Not
Active Active Active
Active
Not
Active
Not
Active
Not
Active
All active as
programmed
Monitoring
active as
programmed.
Fan Drivers
disabled.
ADC, temp
monitor, fan
drivers disabled
All blocks
powered down.
Data retention
on ThermTrip
Status register
only
VDD present,
3V_PWROK# and
VSUS_PWRG
asserted, VDDH
and VDDL present
VDD
VDDH and VDDL
RTC
VDD present,
3V_PWROK# or
VSUS_PWRGD
unasserted, LPM
bit set
VDD
VDDH and VDDL
(if LDO Active)
RTC
VDD present
3V_PWROK# or
VSUS_PWRGD
unasserted, LPM
bit not set
VDD (if LDO
Active)
VDDH and VDDL
(if LDO Active)
RTC
VDD not present RTC
5.4 Fan Control Modes of Operation
The EMC4002 has two modes of operation for the High Side Fan Driver. They are:
1. Manual Mode - in this mode of operation, the user directly controls the fan drive setting. Updating
the Fan Driver Setting Register (see Section 6.32, "Fan Driver Setting Registers") will update the
fan drive based on the programmed ramp rate (default disabled).
The Manual Mode is enabled by clearing the EN_ALGO bit in the Fan Configuration Register
(see Section 6.33, "Fan Configuration 1 Registers").
Whenever the Manual Mode is enabled the current drive settings will be changed to what was
last used by the RPM control algorithm.
Setting the drive value to 00h will disable the High Side Fan Driver for lower power operation.
Changing the drive value from 00h will invoke the Spin Up Routine.
2. Using RPM based Fan Control Algorithm - in this mode of operation, the user determines a target
tachometer reading and the drive setting is automatically updated to achieve this target speed.
DS20005276A-page 30
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