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
I
CCH
=7.5A typ. I
CCL
=400A 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.
1
2
3
TO-92A
3
1
2
MMP-3A
1
V
CC
2
GND
3
V
OUT
1
V
CC
2
GND
3
V
OUT
MITSUMI
System Reset PST574
Equivalent Circuit Diagram
Absolute Maximum Ratings
(Ta=25C)
Electrical Characteristics
(Ta=25C) (Except where noted otherwise, resistance unit is
)
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
1
V
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
1
R
L
=470, V
CC
=L H L
25
50
100
mV
Detection voltage temperature
V
S
/ T
1
R
L
=470, Ta=-20C~+75C
0.01
%/C
coefficient
Low-level output voltage
V
OL
1
V
CC
=V
S
min.-0.05V, R
L
=470
0.1
0.4
V
Output leakage current
I
OH
1
V
CC
=7.5V
0.1
A
Circuit current while on
I
CCL
1
V
CC
=V
S
min.-0.05V, R
L
=
400
650
A
Circuit current while off
I
CCH
1
V
CC
=V
S
typ./0.85V, R
L
=
7.5
12.0
A
"H"transport delay time
tpLH
2
*
1 R
L
=4.7k
, C
L
=100pF
250
400
600
S
"L"transport delay time
tpHL
2
*
1 R
L
=4.7k
, C
L
=100pF
6
20
S
Operation limit voltage
VopL
1
R
L
=4.7k
, V
OL
<
= 0.4V
0.65
0.85
V
Output current while on I
I
OL
I
1
V
CC
=Vs min.-0.05V, R
L
=0
8
30
mA
Output current while on II
I
OL
II
1
*
2 Ta=-20C~+75C, R
L
=0
5
mA
*
1 : tpLH : V
CC
=(V
S
typ.-0.4V) (V
S
typ.+0.4V), tpHL : V
CC
=(V
S
typ.+0.4V) (V
S
typ.-0.4V)
*
2 : V
CC
=V
S
min.-0.15V
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
0
1
2
3
4
5
6
7
8
V
OUT
(V)
V
CC
(V)
Ta=-25
C
Ta=25
C
Ta=75
C
500
400
300
200
100
0
0
1
2
3
4
5
6
7
8
I
CC
(
A)
V
CC
(V)
T
a=-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
V
S
(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.
MITSUMI
System Reset PST574
IoL vs. Ta
VoL vs. Ta
60
50
40
30
20
10
-40
-20
0
20
40
60
80
I
OL
(mA)
Ta (
C)
300
250
200
150
100
50
-40
-20
0
20
40
60
80
V
O
L
(mV)
Ta (
C)
I
CCH
vs. Ta
I
CCL
vs. Ta
9
10
8
7
6
5
4
-40
-20
0
20
40
60
80
l
CCH
(
A)
Ta (
C)
500
400
300
-40
-20
0
20
40
60
80
I
CCL
(
A)
T
a
(
C)
t
PLH
vs. Ta
Pd vs. Ta
-40
-20
0
20
40
60
80
T
a
(
C)
500
600
450
400
350
300
250
t
PLH
(
S)
300
200
0
0
25
50
75
100
125
100
Pd
(mW)
Ta (
C)
6
5
7
4
3
2
1
0
V
CC
/V
OUT
(V)
R
ESET
V
CC
V
OUT
V
S
Time
ON
OFF
Undefined
Timing Chart
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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