HT70XXA-1_13 Datasheet, PDF (5/15 Pages) Holtek Semiconductor Inc – TinyPowerTM Voltage Detector

HT7044A-1
Symbol
Parameter
V_DET
V_HYS
I_DD
V_DD
I_OL
D V DET
DTa
Detection Voltage
Hysteresis Width
Operating Current
Operating Voltage
Output Sink Current
Temperature Coefficient
HT7050A-1
Symbol
Parameter
V_DET
V_HYS
I_DD
V_DD
I_OL
D V DET
DTa
Detection Voltage
Hysteresis Width
Operating Current
Operating Voltage
Output Sink Current
Temperature Coefficient
HT70xxA-1
Test Conditions
V_DD
Conditions
¾
¾
¾
¾
5.4V No load
¾
¾
3.6V V_OUT=0.36V
¾ -40°C<Ta<85°C
Min.
4.268
0.02
V_DET
¾
1.5
3
¾
Typ.
4.400
0.05
V_DET
3
¾
6
±0.9
Ta=25°C
Max. Unit
4.532
0.1
V_DET
6
24
¾
¾
V
V
mA
V
mA
mV/°C
Test Conditions
V_DD
Conditions
¾
¾
¾
¾
6.0V No load
¾
¾
3.6V V_OUT=0.36V
¾ -40°C<Ta<85°C
Ta=25°C
Min.
4.850
0.02
V_DET
¾
2.1
3
¾
Typ.
5.000
0.05
V_DET
3
¾
6
±0.9
Max.
5.150
0.1
V_DET
6
24
¾
¾
Unit
V
V
mA
V
mA
mV/°C
Functional Description
The HT70xxA-1 series is a set of voltage detectors
equipped with a high stability voltage reference which is
connected to the negative input of a comparator¾
denoted as V_REF in the following figure for NMOS output
voltage detector.
When the voltage drop to the positive input of the
comparator (i,e,V_B) is higher than V_REF, VOUT goes
high, M1 turns off, and V_B is expressed as V_BH=V_DD ´
(R_B+R_C) / (R_A+R_B+R_C). If V_DD is decreased so that V_B
falls to a value less than V_REF, the comparator output
inverts from high to low, V_OUT goes low, V_C is high, M1
turns on, RC is bypassed, and V_B becomes: V_BL= V_DD ´
R_B / (R_A+R_B), which is less than V_BH. By so doing, the
comparator output will stay low to prevent the circuit
from oscillating when V_B » V_REF.
If V_DD falls below the minimum operating voltage, the
output becomes undefined. When VDD goes from low to
V_DD ´ R_B / (R_A+R_B) > V_REF, the comparator output and
V_OUT goes high.
The detectable voltage is defined as:
V_DET
(-)
=
RA + RB + RC
RB + RC
´
V_REF
The release voltage is defined as:
V_DET
(+)
=
RA + RB
RB
´
V_REF
The hysteresis width is:
V_HYS = V_DET (+) - V_DET (-)
The figure demonstrates the NMOS output type with
positive output polarity (V_OUT is normally open, active
low). The HT70xxA-1 series also supplies options for
other output types with active high outputs. Application
circuits shown are examples of positive output polarity
(normally open, active low) unless otherwise specified.
V DD
RA
C o m p a ra to r
RL
VC
VB
V OUT
V REF
RB
MN
M1
RC
V SS
NMOS Output Voltage Detector
Rev. 2.00
5
April 30, 2013