RT8473 Datasheet PDF - Richtek

www.Datasheet-PDF.com

RT8473
Richtek

Part Number RT8473
Description High Brightness LED Driver
Page 12 Pages


RT8473 datasheet pdf
Download PDF
RT8473 pdf
View PDF for Mobile

No Preview Available !

®
RT8473
1A, Hysteretic, High Brightness LED Driver with Internal
Switch
General Description
The RT8473 is a high efficiency, continuous mode inductive
step-down converter, designed for driving single or multiple
series connected LEDs from a voltage source higher than
the LED voltage. It operates from an input voltage of 7V to
30V and employs hysteretic control with a high side current
sense resistor to set the constant output current.
The RT8473 includes an output switch and a high side
output current sensing circuit, which uses an external
resistor to set the nominal average output current. LED
brightness control is achieved with PWM dimming from
an analog or PWM input signal.
The RT8473 is available in a small TSOT-23-5 package.
Ordering Information
RT8473
Package Type
J5 : TSOT-23-5
Note :
Lead Plating System
G : Green (Halogen Free and Pb Free)
Richtek products are :
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
05=DNN
05= : Product Code
DNN : Date Code
Features
z 7V to 30V Input Voltage Range
z Hysteretic Control with High Side Current Sensing
z Internal N-MOSFET with 350mΩ Low RDS(ON)
z 1A Output Current
z Up to 97% Efficiency
z Typical ±5% LED Current Accuracy
z Analog or PWM Control Signal for LED Dimming
z 300Hz On-Board Ramp Generator
z Input Under Voltage Lockout
z Thermal Shutdown Protection
z RoHS Compliant and Halogen Free
Applications
z Automotive LED Lighting
z High Power LED Lighting
z Indicator and Emergency Lighting
z Architectural Lighting
z Low Voltage Industrial Lighting
z Signage and Decorative LED Lighting
Pin Configurations
(TOP VIEW)
VIN SENSE
54
23
LX GND ADJ
TSOT-23-5
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8473-00 January 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



No Preview Available !

RT8473
Typical Application Circuit
VIN
7V to 30V
C1
10µF/50V
optional
C2
VIN = 7V to 30V
VOUT = 3.5V
IOUT = 1A
optional
R1
100m
RT8473
5 VIN
3 ADJ
SENSE
4
LED+
R2
optional
C3
2 GND
LED-
LX 1
L1
100µH
D1
SR26
optional
R3
C4
Functional Pin Description
Pin No.
1
2
3
4
5
Pin Name
LX
GND
ADJ
SENSE
VIN
Pin Function
Switching Node. Open drain output of internal N-MOSFET.
Ground.
Dimming Control Input :
--- Analog signal input for analog PWM dimming.
--- PWM signal input for digital PWM dimming.
Output Current Sense Terminal. Sense LED string current.
Supply Input Voltage.
Function Block Diagram
VIN
Regulator
Bandgap
UVLO
UVLO
VCC
1.25V
+
-
Ramp Gen.
+ Dimming
ADJ -
SENSE
UVLO
Dimming
MOSFET
LX
GND
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS8473-00 January 2012



No Preview Available !

RT8473
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VIN ------------------------------------------------------------------------------------- 0.3V to 33V
z Switch Voltage, LX --------------------------------------------------------------------------------------------- 0.3V to (VIN + 0.7V)
z Sense Voltage, SENSE -------------------------------------------------------------------------------------- (VIN 5V) to (VIN + 0.3V)
z All Other Pins ----------------------------------------------------------------------------------------------------- 0.3V to 6V
z Power Dissipation, PD @ TA = 25°C
TSOT-23-5 (Single-layer PCB) ------------------------------------------------------------------------------- 0.400W
TSOT-23-5 (Four-layer PCB) --------------------------------------------------------------------------------- 0.625W
z Package Thermal Resistance (Note 2)
TSOT-23-5, θJA (Single-layer PCB) ------------------------------------------------------------------------- 250°C/W
TSOT-23-5, θJC (Single-layer PCB) ------------------------------------------------------------------------- 130°C/W
TSOT-23-5, θJA (Four-layer PCB) --------------------------------------------------------------------------- 160°C/W
z Junction Temperature ------------------------------------------------------------------------------------------ 150°C
z Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------- 260°C
z Storage Temperature Range --------------------------------------------------------------------------------- 65°C to 150°C
z ESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------- 2kV
MM (Machine Mode) ------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, VIN ------------------------------------------------------------------------------------- 7V to 30V
z Junction Temperature Range --------------------------------------------------------------------------------- 40°C to 125°C
Electrical Characteristics
(VIN = 12V, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Test Conditions
Mean Current Sense Threshold
Voltage
VSENSE
Measure on SENSE Pin with
Respect to VIN. ADJ pin is
Floating.
Sense Threshold Hysteresis
MOSFET On-Resistance
MOSFET Leakage Current
Under Voltage Lockout Threshold
Under Voltage Lockout Threshold
Hysteresis
Ramp Frequency
VSENSEHYS
RDS(ON)
VUVLO
VLX = 5V
VIN Rising
ΔVUVLO
fRAMP
ADJ Input Threshold Logic-High VADJ_H
Voltage
Logic-Low VADJ_L
Analog Dimming Range
Minimum Switch On Time
Minimum Switch Off Time
Quiescent Supply Current with
Output Off
tON(MIN)
tOFF(MIN)
IVIN, Off
LX Switch On
LX Switch Off
VADJ = 0V
Min Typ Max Unit
95 100 105 mV
-- ±5 -- %
-- 350 -- mΩ
-- 0.01 10 μA
-- 5.2 --
V
-- 400 -- mV
-- 300 --
1.4 -- 5.5
-- -- 0.2
0.4 -- 1.2
-- 210 --
-- 170 --
Hz
V
V
ns
ns
-- 450 --
μA
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
DS8473-00 January 2012
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3



No Preview Available !

RT8473
Parameter
Quiescent Supply Current with
Output Switching
Internal Propagation Delay
Sense Pin Input Current
Thermal Shutdown
Thermal Shutdown Hysteresis
Symbol
IVIN, On
tPD
ISENSE
TSD
ΔTSD
Test Conditions
ADJ Pin is Floating, fSW = 250kHz,
VIN = 8V
VSENSE = VIN – 0.1V
Min
--
--
--
--
--
Typ
1000
25
300
150
30
Max
--
--
--
--
--
Unit
μA
ns
nA
°C
°C
Note 1. Stresses beyond those listed Absolute Maximum Ratingsmay cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2. θJA is measured at TA = 25°C on a single-layer and four-layer test board of JEDEC 51. The measurement case position
of θJC is on the lead of the package.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Copyright ©2012 Richtek Technology Corporation. All rights reserved.
www.richtek.com
4
is a registered trademark of Richtek Technology Corporation.
DS8473-00 January 2012



RT8473 datasheet pdf
Download PDF
RT8473 pdf
View PDF for Mobile


Related : Start with RT847 Part Numbers by
RT8470 High Brightness LED Driver RT8470
Richtek
RT8470 pdf
RT8471 High Brightness LED Driver RT8471
Richtek
RT8471 pdf
RT8472 High Brightness LED Driver RT8472
Richtek
RT8472 pdf
RT8473 High Brightness LED Driver RT8473
Richtek
RT8473 pdf
RT8474 High Voltage Multiple-Topology LED Driver RT8474
Richtek
RT8474 pdf
RT8474A High Voltage Multiple-Topology LED Driver RT8474A
Richtek
RT8474A pdf
RT8475 High Voltage High Current LED Driver Controller RT8475
Richtek
RT8475 pdf
RT8476 Two-Stage Hysteretic LED Driver Controller RT8476
Richtek
RT8476 pdf

Index :   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z   

This is a individually operated, non profit site. If this site is good enough to show, please introduce this site to others.
Since 2010   ::   HOME   ::   Contact