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
1.
2.
3.
4.
5.
Ultra-low current consumption
Low operating limit voltage
Output current high for ON
Hysteresis voltage provided in detection voltage
Built-in delay circuit with excellent delay time
temperature characteristics
6. 10 ranks of detection voltage
I
CCH
=7.5µA typ. I
CCL
=400µA typ.
0.65V typ.
30mA typ.
50mV typ.
50mV typ.
PST574
C : 4.5V typ.
D : 4.2V typ.
E : 3.9V typ.
F : 3.6V typ.
G : 3.3V typ.
H : 3.1V typ.
I : 2.9V typ.
J : 2.7V typ.
K : 2.5V typ.
L : 2.3V typ.
Package
MMP-3A (PST574 M)
TO-92A (PST574 )
contains detection voltage rank .
*
Applications
1.
2.
3.
4.
5.
Reset circuits in microcomputers, CPUs and MPUs (especially multi-CPU sets)
Logic circuit reset circuits.
Battery voltage check circuits.
Back-up power supply switching circuits.
Level detection circuits.
Pin Assignment
1
2
3
V
CC
GND
V
OUT
1
3
1
2
V
CC
GND
V
OUT
2
3
1
2
3
MMP-3A
TO-92A
MITSUMI
System Reset PST574
Equivalent Circuit Diagram
Absolute Maximum Ratings
Item
Storage temperature
Operating temperature
Power supply voltage
Allowable loss
(Ta=25°C)
Symbol
T
STG
T
OPR
V
CC
max.
Pd
Rating
-40~+125
-20~+75
-0.3~10
200 (MMP-3A)
300 (TO-92A)
Units
°C
°C
V
mW
Electrical Characteristics
Item
(Ta=25°C) (Except where noted otherwise, resistance unit is
Ω)
Measurement
Measurement conditions
circuit
PST574C
PST574D
PST574E
PST574F
R
L
=470
PST574G
1
V
OL
< 0.4V
=
PST574H
V
CC
=H L
PST574I
PST574J
PST574K
PST574L
1
R
L
=470, V
CC
=L H L
1
1
1
1
1
2
2
1
1
1
R
L
=470, Ta=-20°C~+75°C
V
CC
=V
S
min.-0.05V, R
L
=470
V
CC
=7.5V
V
CC
=V
S
min.-0.05V, R
L
=∞
V
CC
=V
S
typ./0.85V, R
L
=∞
1 R
L
=4.7kΩ, C
L
=100pF
1 R
L
=4.7kΩ, C
L
=100pF
R
L
=4.7kΩ, V
OL
< 0.4V
=
V
CC
=Vs min.-0.05V, R
L
=0
2 Ta=-20°C~+75°C, R
L
=0
Min. Typ. Max. Units
4.3
4.0
3.7
3.4
3.1
2.9
2.75
2.55
2.35
2.15
25
4.5
4.2
3.9
3.6
3.3
3.1
2.90
2.70
2.50
2.30
50
±0.01
0.1
400
7.5
400
6
0.65
30
0.4
±0.1
650
12.0
600
20
0.85
4.7
4.4
4.1
3.8
3.5
3.3
3.05
2.85
2.65
2.45
100
Symbol
Detection voltage
V
S
V
Hysteresis voltage
Detection voltage temperature
coefficient
Low-level output voltage
Output leakage current
Circuit current while on
Circuit current while off
"H"transport delay time
"L"transport delay time
Operation limit voltage
Output current while on
I
Output current while on
II
tpLH
=(V typ.-0.4V)
*
1 :: V =V: Vmin.-0.15V
*
2
CC
S
CC
S
V
S
V
S
/ T
V
OL
I
OH
I
CCL
I
CCH
tpLH
tpHL
VopL
I
OL
I
I
OL
II
mV
%/°C
V
µA
µA
µA
µS
µS
V
mA
mA
*
*
*
250
8
5
(V
S
typ.+0.4V), tpHL : V
CC
=(V
S
typ.+0.4V)
(V
S
typ.-0.4V)
MITSUMI
System Reset PST574
Measuring Circuit
[1]
[2]
0.8V
4.9
V
S
4.1
0V
Note: Input model is an example for PST574C.
Characteristics
Vcc vs. V
OUT
8
7
6
(Example: PST574C)
Vcc vs. Icc
500
400
300
Ta=75
°C
Ta=-20°C
Ta=25
°C
V
OUT
(V)
4
3
2
1
0
1
Ta=-25°C
Ta=25°C
Ta=75°C
5
I
CC
(µA)
200
100
0
0
1
2
3
4
5
6
7
8
2
3
4
5
6
7
8
V
CC
(V)
V
CC
(V)
Vs vs. Ta
4.53
4.52
4.51
Vs vs. Ta
80
70
60
V
S
4.50
(V)
4.49
4.48
4.47
-40
-20
0
20
40
60
80
V
S
50
(mV)
40
30
20
-40
-20
0
20
40
60
80
T
a
(°C)
T
a
(°C)
MITSUMI
System Reset PST574
IoL vs. Ta
60
50
VoL vs. Ta
300
250
I
OL
40
(mA)
30
20
10
-40
-20
0
20
40
60
80
V
O
L
200
(mV)
150
100
50
-40
-20
0
20
40
60
80
Ta (°C)
Ta (°C)
I
CCH
vs. Ta
10
9
8
I
CCL
vs. Ta
500
l
CCH
(µA)
7
6
5
4
-40
-20
0
20
40
60
80
I
CCL
400
(µA)
300
-40
-20
0
20
40
60
80
Ta (°C)
T
a
(°C)
t
PLH
vs. Ta
600
500
450
Pd vs. Ta
300
t
PLH
(µS)
200
400
350
300
250
-40
-20
0
20
40
60
80
Pd
(mW)
100
0
0
25
50
75
100
125
T
a
(°C)
Ta (°C)
Timing Chart
7
6
5
4
3
2
1
0
V
CC
V
S
V
OUT
V
CC
/V
OUT
(V)
Time
R
ESET
ON
OFF
Undefined
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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