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MITSUMI
System Reset PST574
System Reset
Monolithic IC PST574
Outline
This IC functions in a variety of CPU systems and other logic systems, to detect power supply voltage and
reset the system accurately when power is turned on or interrupted. This ultra-low current consumption low
reset type system reset IC has a built-in fixed delay time generating circuit. It is ideal for use in multi-CPU
systems because a fast-rising output waveform can be obtained.
Features
Package
Applications
Pin Assignment
1. Ultra-low current consumption ICCH=7.5µA typ. ICCL=400µA typ.
2. Low operating limit voltage 0.65V typ.
3. Output current high for ON 30mA typ.
4. Hysteresis voltage provided in detection voltage 50mV typ.
5. Built-in delay circuit with excellent delay time 50mV typ.
temperature characteristics
6. 10 ranks of detection voltage PST574 C : 4.5V typ. H : 3.1V typ.
D : 4.2V typ. I : 2.9V typ.
E : 3.9V typ. J : 2.7V typ.
F : 3.6V typ. K : 2.5V typ.
G : 3.3V typ. L : 2.3V typ.
MMP-3A (PST574 M)
TO-92A (PST574 )
*
contains detection voltage rank .
1. Reset circuits in microcomputers, CPUs and MPUs (especially multi-CPU sets)
2. Logic circuit reset circuits.
3. Battery voltage check circuits.
4. Back-up power supply switching circuits.
5. Level detection circuits.
123
TO-92A
31
2
MMP-3A
1 VCC
2 GND
3 V
OUT
1 VCC
2 GND
3 V
OUT
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MITSUMI
System Reset PST574
Equivalent Circuit Diagram
Absolute Maximum Ratings
(Ta=25°C)
Electrical Characteristics
(Ta=25°C) (Except where noted otherwise, resistance unit is Ω)
Item Symbol Rating Units
Storage temperature T
STG
-
40~+125 °C
Operating temperature T
OPR
-
20~+75 °C
Power supply voltage V
CC max.
-
0.3~10 V
Allowable loss Pd
200 (MMP-3A)
mW
300 (TO-92A)
Item Symbol
Measurement
Measurement conditions Min. Typ. Max. Units
circuit
PST574C 4.3 4.5 4.7
PST574D 4.0 4.2 4.4
PST574E 3.7 3.9 4.1
R
L=470
PST574F 3.4 3.6 3.8
Detection voltage V
S
1V
OL
<
=
0.4V
PST574G 3.1 3.3 3.5
V
V
CC=H L
PST574H 2.9 3.1 3.3
PST574I 2.75 2.90 3.05
PST574J 2.55 2.70 2.85
PST574K 2.35 2.50 2.65
PST574L 2.15 2.30 2.45
Hysteresis voltage V
S 1RL=470, VCC=L H L 25 50 100 mV
Detection voltage temperature
VS/ T 1 RL=470, Ta=-20°C~+75°C ±0.01 %/°C
coefficient
Low-level output voltage V
OL 1
VCC=VSmin.-0.05V, RL=470
0.1 0.4 V
Output leakage current I
OH 1VCC=7.5V ±0.1 µA
Circuit current while on I
CCL 1VCC=VS min.
-
0.05V, RL=∞ 400 650 µA
Circuit current while off I
CCH 1VCC=VS typ./0.85V, RL=∞ 7.5 12.0 µA
"H"transport delay time tpLH 2
*
1 RL=4.7kΩ, CL=100pF 250 400 600 µS
"L"transport delay time tpHL 2
*
1 RL=4.7kΩ, CL=100pF 6 20 µS
Operation limit voltage VopL 1 R
L=4.7kΩ, VOL
<
=
0.4V 0.65 0.85 V
Output current while on II
OL I1VCC=Vs min.
-
0.05V, RL=0 8 30 mA
Output current while on II I
OL II 1
*
2 Ta=-20°C~+75°C, RL=0
5mA
*
1 : tpLH : VCC=(VS typ.-0.4V) (VS typ.+0.4V), tpHL : VCC=(VS typ.+0.4V) (VS typ.-0.4V)
*
2 : VCC=VS min.-0.15V
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MITSUMI
System Reset PST574
Measuring Circuit
Characteristics
(Example: PST574C)
[1] [2]
Vcc vs. V
OUT Vcc vs. Icc
8
7
6
5
4
3
2
1
012345678
VOUT
(V)
V
CC (V)
Ta
=
-
25°C
Ta
=
25°C
Ta
=
75°C
500
400
300
200
100
0
012345678
ICC
(µA)
V
CC (V)
Ta
=
-
20°C
T
a
=
25
°C
T
a
=
75
°C
Vs vs. Ta Vs vs. Ta
-
40-20 0 20 40 60 80
4.47
4.48
4.49
4.50
4.51
4.52
4.53
VS
(V)
T
a (°C)
V
S
(mV)
T
a (°C)
-
40-20 0 20 40 60 80
20
30
40
50
60
70
80
0.8V
V
S
0V
4.9
4.1
Note: Input model is an example for PST574C.
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MITSUMI
System Reset PST574
IoL vs. Ta VoL vs. Ta
60
50
40
30
20
10
-
40-200 20406080
IOL
(mA)
T
a (°C)
300
250
200
150
100
50
-
40-200 20406080
VOL
(mV)
T
a (°C)
ICCH vs. Ta ICCL vs. Ta
9
10
8
7
6
5
4
-
40-200 20406080
lCCH
(µA)
T
a (°C)
500
400
300
-
40-200 20406080
ICCL
(µA)
T
a (°C)
tPLH vs. Ta
Pd vs. Ta
-
40-200 20406080
Ta (°C)
500
600
450
400
350
300
250
tPLH
(µS)
300
200
0
0 25 50 75 100 125
100
Pd
(mW)
Ta (°C)
6
5
7
4
3
2
1
0
VCC /VOUT
(V)
R
ESET
VCC
VOUT
VS
Time
ON
OFF
Undefined
Timing Chart
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MITSUMI
System Reset PST574
Application circuits
1. Normal hard reset
Note: Connect a capacitor between IC pins 1 and 2
if V
CC line impedance is high.
2. Battery checker (LED ON for high voltage)
Note: Connect a capacitor between IC pins 1 and 2
if V
CC line impedance is high.
3. Battery checker (LED ON for low voltage)
Note: Connect a capacitor between IC pins 1 and 2
if V
CC line impedance is high.
4. Hysteresis voltage UP method
When increasing hysteresis voltage for stable system
operation, determine RH as follows and connect
externally.
However, I
CCH is
-
5000PPM/°C, so perform
temperature compensation at RH when using over a
wide temperature range.
Hysteresis voltage UP amount ( Vsup) is
Vsup .=.RH I
CCL
Total hysteresis voltage ( Vstotal) is
Vstotal .=.Vs + Vsup
(Operation will be destabilized if RH is raised too
much.)
Note: Connect a capacitor between IC pins 1 and 2 if
V
CC line impedance is high.
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