HT7022A Datasheet PDF - Holtek Semiconductor

www.Datasheet-PDF.com

HT7022A
Holtek Semiconductor

Part Number HT7022A
Description 2.2V Voltage Detector
Page 12 Pages


HT7022A datasheet pdf
Download PDF
HT7022A pdf
View PDF for Mobile


No Preview Available !

HT7022A
2.2V Voltage Detector
Features
· Low detectable voltage 2.2V
· Low power consumption
· Low temperature coefficient
· Built-in high-stability reference source
· Built-in hysteresis characteristic
· TO-92 and SOT-89 package
Applications
· Battery checkers
· Power failure detectors
· Microcomputer reset
· Battery memory backup
· Non-volatile RAM signal storage protectors
General Description
The HT7022A is a three-terminal low power voltage de-
tector implemented in CMOS technology. It detects a
particular fixed voltage 2.2V. The voltage detector con-
sists of a high-precision and low power consumption
standard voltage source, a comparator, hysteresis cir-
cuit, and an output driver. CMOS technology ensures
low power consumption.
Although designed primarily as fixed voltage detectors,
these devices can be used with external components to
detect user specified threshold voltages (NMOS open
drain type only).
Output Type Selection Table
Type
VOUT
VDD
A
VDD>VDET(+)
Hi-Z
VDD£VDET(-)
VSS
Rev. 1.10
1 April 20, 2004



No Preview Available !

Block Diagram
N Channel Open Drain Output (Normal Open; Active Low)
VDD
HT7022A
VO UT
V REF
GND
A Type
V OUT
Pin Assignment
D a s h lin e
S o lid lin e
V IN fr o m L O ® H I
V IN fr o m H I ® L O
V D E T V D E T ´ 1 .0 5
V HYS
V IN
T O -9 2
S O T -8 9
H T7022A
F r o n t V ie w
H T7022A
O UT VDD VSS
B o tto m V ie w
O UT VDD VSS
Rev. 1.10
2 April 20, 2004



No Preview Available !

Pad Assignment
12
3
(0 ,0 )
HT7022A
Chip size: 2032 ´ 1321 (mm)2
* The IC substrate should be connected to VDD in the PCB layout artwork.
Pad Coordinates
Pad No.
1
2
3
X
-434.34
120.65
774.70
Unit: mm
Y
394.97
461.01
412.75
Absolute Maximum Ratings
Supply Voltage ............................VSS-0.3V to VSS+13V
Output Current......................................................50mA
Power Consumption ..........................................200mW
Output Voltage...........................VSS-0.3V to VDD+0.3V
Storage Temperature ............................-50°C to 125°C
Operating Temperature...........................-40°C to 85°C
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings² may
cause substantial damage to the device. Functional operation of this device at other conditions beyond those
listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliabil-
ity.
Electrical Characteristics
Symbol
Parameter
VDET
VHYS
IDD
VDD
IOL
DVDET
DTa
Hi®Lo Detectable Voltage
Lo®Hi Detectable Voltage
Hysteresis Width
Operating Current
Operating Voltage
Output Sink Current
Temperature Coefficient
Test Conditions
VDD Conditions
¾¾
¾¾
¾¾
3.2V No load
¾¾
2V VOUT=0.2V
¾ 0°C<Ta<70°C
Ta=25°C
Min.
Typ.
Max.
Unit
2.09
2.2
2.132
2.31
0.02VDET 0.05VDET
¾ 1.8
1.6 ¾
0.5 1
2.31
2.541
0.1VDET
4
12
¾
V
V
V
mA
V
mA
¾ ±0.9 ¾ mV/°C
Rev. 1.10
3 April 20, 2004



No Preview Available !

HT7022A
Functional Description
The HT7022A is a voltage detector equipped with a high
stability voltage reference which is connected to the
negative input of a comparator¾ denoted as VREF in the
following figure for NMOS output voltage detector.
When the voltage drop to the positive input of the com-
parator (i,e,VB) is higher than VREF, VOUT goes high,
M1 turns off, and VB is expressed as VBH=VDD ´
(RB+RC) / (RA+RB+RC). If VDD is decreased so that VB
falls to a value less than VREF, the comparator output in-
verts from high to low, VOUT goes low, VC is high, M1
turns on, RC is bypassed, and VB becomes:
VBL=VDD´RB / (RA+RB), which is less than VBH. By so
doing, the comparator output will stay low to prevent the
circuit from oscillating when VB » VREF.
If VDD falls below the minimum operating voltage, the
output becomes undefined. When VDD goes from low to
VDD ´ RB / (RA+RB) > VREF, the comparator output and
VOUT goes high.
The detectable voltage is defined as:
VDET
(-)
=
RA + RB + RC
RB + RC
´
VREF
The release voltage is defined as:
VDET
(+)
=
RA + RB
RB
´
VREF
The hysteresis width is:
VHYS = VDET (+) - VDET (-)
The figure demonstrates the NMOS output type with
positive output polarity (VOUT is normally open, active
low).
V DD
RA
C o m p a ra to r
RL
VC
V B V OUT
V REF
RB
MN
M1
RC
V SS
NMOS Output Voltage Detector
Application Circuits
Microcomputer Reset Circuit
Normally a reset circuit is required to protect the micro-
computer system from malfunctions due to power line
interruptions. The following examples show how differ-
ent output configurations perform a reset function in var-
ious systems.
· NMOS open drain output application for separate
power supply
V DD1
V DD2
H T7022A
V OUT
RESET
M ic r o -
c o m p u te r
· NMOS open drain output application with R-C delay
V DD
H T7022A
V OUT
R
M ic r o -
c o m p u te r
C
V SS
V SS
Rev. 1.10
4 April 20, 2004



HT7022A datasheet pdf
Download PDF
HT7022A pdf
View PDF for Mobile


Related : Start with HT7022 Part Numbers by
HT7022A 2.2V Voltage Detector HT7022A
Holtek Semiconductor
HT7022A 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