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.
sc
on
PST574
1
3
2
MMP-3A
Package
MMP-3A (PST574 M)
TO-92A (PST574 )
contains detection voltage rank .
Pin Assignment
Pr
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.
od
uc
Applications
1
2
3
ts
*
to
V
CC
GND
V
OUT
be
di
C : 4.5V typ.
D : 4.2V typ.
E : 3.9V typ.
F : 3.6V typ.
G : 3.3V typ.
tin
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.
ue
H : 3.1V typ.
I : 2.9V typ.
J : 2.7V typ.
K : 2.5V typ.
L : 2.3V typ.
1
2
3
V
CC
GND
V
OUT
1
2
3
TO-92A
d
Features
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
tin
200 (MMP-3A)
300 (TO-92A)
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
di
Symbol
sc
on
*
*
*
ue
°C
V
mW
°C
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
V
mV
%/°C
V
µA
µA
µA
µS
µS
V
mA
mA
250
8
5
Detection voltage
uc
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
od
ts
to
V
S
V
S
V
S
/ T
V
OL
I
OH
I
CCL
I
CCH
tpLH
tpHL
VopL
I
OL
I
I
OL
II
be
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
tpLH
=(V typ.-0.4V)
*
1 :: V =V: Vmin.-0.15V
*
2
CC
S
CC
S
Pr
(V
S
typ.+0.4V), tpHL : V
CC
=(V
S
typ.+0.4V)
(V
S
typ.-0.4V)
d
Units
MITSUMI
System Reset PST574
Measuring Circuit
[1]
[2]
0.8V
4.9
V
S
4.1
0V
Vcc vs. V
OUT
8
7
6
5
3
2
1
0
1
Ta=-25°C
Ta=25°C
Ta=75°C
Vcc vs. Icc
500
400
300
sc
on
di
I
CC
(µA)
tin
Ta=-20°C
Ta=25
°C
Ta=75
°C
Characteristics
(Example: PST574C)
V
OUT
(V)
4
be
7
8
200
100
0
0
1
2
3
4
5
6
7
8
2
3
4
5
6
V
CC
(V)
ts
to
Vs vs. Ta
4.53
4.52
4.51
uc
Vs vs. Ta
80
70
60
Pr
od
V
S
4.50
(V)
4.49
4.48
4.47
V
S
50
(mV)
40
30
20
-40
-20
0
20
40
60
80
-40
-20
ue
V
CC
(V)
0
20
40
60
80
T
a
(°C)
d
T
a
(°C)
Note: Input model is an example for PST574C.
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
6
5
4
-40
-20
0
20
40
60
80
sc
on
300
-40
-20
l
CCH
(µA)
7
I
CCL
400
(µA)
tin
0
20
40
60
80
di
Pd vs. Ta
300
200
Ta (°C)
t
PLH
vs. Ta
600
500
450
uc
350
300
250
ts
t
PLH
(µS)
to
be
400
Pd
(mW)
100
od
-40
-20
0
20
40
60
80
0
0
25
50
75
100
125
Timing Chart
7
6
5
4
3
2
1
0
V
CC
V
S
V
OUT
Pr
T
a
(°C)
V
CC
/V
OUT
(V)
Time
R
ESET
ON
OFF
Undefined
ue
T
a
(°C)
Ta (°C)
d
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)
3. Battery checker (LED ON for low voltage)
to
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.
Pr
od
uc
ts
be
Note: Connect a capacitor between IC pins 1 and 2
if V
CC
line impedance is high.
di
sc
on
Note: Connect a capacitor between IC pins 1 and 2
if V
CC
line impedance is high.
tin
ue
d
MCU
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