MITSUMI
System Reset PST611
System Reset
Monolithic IC PST611
Outline
This IC functions in a variety of CPU systems and other logic systems, to constantly monitor power supply
voltage, and to reset the system accurately when power is turned on or interrupted.
System reset ICs have been represented by the PST series in the past, but this IC is able to set no-response
time through an external capacitor, and controls reset output relative to temporary power supply voltage drop
caused by motor load or the like in systems using batteries.
Also, the detection voltage for this IC is set low so that it can respond to systems that operate on low voltage.
Features
1. Low current consumption
I
CCH
=2.2µA
I
CCL
=3.2µA
2. Low operating limit voltage
0.75V max.
3. High reset output
4. No-response time can be controlled
5. 8 types of detection voltages provided
PST611
R : 1.6V typ.
V : 1.2V typ.
S : 1.5V typ.
W : 1.1V typ.
T : 1.4V typ.
X : 1.0V typ.
U : 1.3V typ.
Y : 0.9V typ.
Package
MMP-4A (PST611 M)
*
contains detection voltage rank.
Applications
1. Reset circuits in microcomputers, CPUs and MPUs
2. Set voltage drop detection
3. Battery voltage check circuits.
4. Voltage detection circuits in general
Absolute Maximum Ratings
(Ta=25
°
C)
Item
Symbol
Rating
Units
Storage temperature
T
STG
-40~+125
°
C
Operating temperature
T
OPR
-10~+70
°
C
Power supply voltage
V
CC
max.
-0.3~+5
V
Allowable loss
Pd
200
mW
MITSUMI
System Reset PST611
Equivalent Circuit Diagram
Electrical Characteristics
(Ta=25
°
C)
Note: Characteristics other than for detection voltage use the 1.0V(X) type as a representative example.
Pin Assignment
Item
Symbol
Measurement conditions
Min. Typ. Max. Units
Consumption current
I
CC
H
V
CC
=0.95V, VR=OPEN
2.2
µA
I
CC
L
V
CC
=1.2V, VR=OPEN
3.2
µA
R
1.552
1.6
1.648
V
S
1.455
1.5
1.545
V
T
1.358
1.4
1.442
V
Detection voltage
Vs
V
CC
: variable=3V
U
1.261
1.3
1.339
V
V
1.164
1.2
1.236
V
W
1.067
1.1
1.133
V
X
0.970
1.0
1.030
V
Y
0.873
0.9
0.927
V
TC pin charge current
I
TC
1
V
CC
=1.2V, V
TC
=0.4V, VR=3V
0.1
µA
TC pin discharge current
I
TC
2
V
CC
=0.95V, V
TC
=0.1V, VR=3V
0.05
µA
TC pin discharge resistance
R
TC
V
CC
=0V, V
TC
=0.1V, VR=0V
16
33
66
MEG
Ω
Detection voltage temperature coefficient
Vs
±200
ppm
TC pin threshold
V
THTC
V
CC
=1.0V, V
TC
: variable=3V
0.06
0.08
0.10
V
TC pin hysteresis voltage
V
THTCH
V
CC
=1.0V, V
TC
: variable=3V
0.06
0.09
0.12
V
R output leakage current
I
LEAK
V
CC
=0.95V, VR=3V
0.1
µA
R output sync current
I
OL
V
CC
=1.0V, V
TC
=0.4V, VR=0.4V
15
50
µA
Operation limit voltage
V
OPL
V
CC
: variable V
TC
=0.4V, VR=3V
0.7
0.75
V
1
2
4
3
MMP-4A
1
R
OUT
2
V
CC
3
T
C
4
GND
MITSUMI
System Reset PST611
Measuring Circuit
Measurement Method
Measurement conditions
Item
V
CC
V
TC
VR
SW1
SW2
Measured
value
Consumption current
1.2V
-
-
OFF
3
A1
Detection voltage
Variable
-
3V
OFF
1
V1
TC pin charge current
1.2V
0.4V
3V
ON
1
A2
TC pin discharge current
0.95V
0.2V
3V
ON
1
A2
TC pin discharge resistance
0V
0.1V
0V
ON
1
A2
TC pin threshold
1.0V
Variable
3V
ON
1
V3
TC pin hysteresis voltage
1.0V
Variable
3V
ON
1
V3
R output leakage current
0.95V
-
3V
OFF
2
A3
R output sync current
1.0V
0.4V
0.4V
ON
2
A3
Operation limit voltage
Variable
0.4V
3V
OFF
1
V1
Reference
Measure A1 value.
Gradually lower V
CC
from
1.2V and measure the value
of V1 when V2 value
switches from low to high.
Measure A2 value.
Measure A2 value.
0.1V/A2 value
Gradually lower V
TC
from
0.3V and measure the value
of V3 when V2 value
switches from low to high.
(V
THTC
)
The value of V3 when V2
switches from high to low
while raising V
TC
from 0.0V,
minus "V
THTC
."
Measure A3K value.
Measure A3 value.
The limit voltage within
which V2 value stays low
while lowering V
CC
from
1.0V.
MITSUMI
System Reset PST611
Application circuits
1. How to change reset output logic
Note: Set R1 so that V1 > threshold voltage.
2. How to change detection voltage (detection voltage UP)
Note: Set R1 so that the value of I
1
is sufficient
to ignore I
CC
.
3 Battery checker (LED ON for high voltage)
Note: When V
CC
is less than LED VF, take LED
lamp power from DC-DC converter or
other output.
