MITSUMI
System Reset PST596~598
System Reset
Monolithic IC PST596~598 Series
Outline
These ICs function 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, and has a built-in fixed delay time
generating circuit. This series has been represented in the past by PST591~595, and these new system reset
ICs offer ultra-small size and low current consumption.
Features
1. Fixed delay time setting by counter timer
2. Low operating limit voltage
0.65V typ.
3. Hysteresis voltage provided in detection voltage
50mV typ.
4. Low current consumption
I
CCH
=15A typ.
5. 3 delay time products available
PST596
50ms
PST597 100ms
PST598 200ms
6. Each product has 10 detection voltage ranks.
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.
Package
SOT-25A (PST59 N) (with manual reset pin)
*
contains detection voltage rank.
Applications
1. Reset circuits in microcomputers, CPUs and MPUs
2. Logic circuit reset circuits.
3. Battery voltage check circuits.
4. Back-up power supply switching circuits.
5. Level detection circuits.
6. Mechanical reset circuits
MITSUMI
System Reset PST596~598
Equivalent Circuit Diagram
Pin Assignment
5
4
3
2
1
SOT-25
(TOP VIEW)
1
M/R
2
SUB
3
GND
4
V
OUT
5
V
CC
Pin Description
Pin No.
Pin name
Function
1
M/R
Manual reset pin
*
1
2
SUB
SUB pin
*
2
3
GND
GND pin
4
V
OUT
Reset signal output pin
5
V
CC
Power supply pin/Voltage detection pin
Absolute Maximum Ratings
(Ta=25
C)
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~+12
V
Manual reset input voltage
V
RES
max.
-0.3~+12
V
Allowable loss
Pd
150
mW
*
1: Note that the oscilloscope may mis-operate if the M/R pin falls below -0.3V.
*
2: Connect to GND.
MITSUMI
System Reset PST596~598
Electrical Characteristics
(Ta=25
C) (Except where noted otherwise, resistance unit is
)
*
1 : T
PLH
; V
CC
= (Vs typ.-0.4V) (Vs typ.+0.4V)
*
2 : T
PLH
; V
CC
= (Vs typ.+0.4V) (Vs typ.-0.4V)
Note 3: Connect manual reset pin to GND when not using.
Recommended Operating Conditions
Item
Symbol
Rating
Units
Operating temperature
T
OPR
-20~+75
C
Power supply voltage
V
CC
-0.3~+12
V
Item
Symbol Measuring circuit
Measurement conditions
Min. Typ. Max. Units
C
4.3
4.5
4.7
D
4.0
4.2
4.4
E
3.7
3.9
4.1
V
CC
=H L
F
3.4
3.6
3.8
Detection voltage
Vs
1
R
L
=470
G
3.1
3.3
3.5
V
V
OL
<
= 0.4V
H
2.9
3.1
3.3
I
2.75 2.90 3.05
J
2.55 2.70 2.85
K
2.35 2.50 2.65
L
2.15 2.30 2.45
Hysteresis voltage
Vs
1
V
CC
=L H L, R
L
=470
30
50
100
mV
Detection voltage
temperature coefficient
Vs/ T
1
R
L
=470, Ta=-20
C~+75
C
0.01
%/
C
Low-level output voltage
V
OL
1
V
CC
=Vs min. -0.05V, R
L
=470
0.1
0.4
V
Output leakage current
I
OH
1
V
CC
=10V
0.1
A
Circuit current while on
I
CCL
1
V
CC
=Vs min. -0.05V, R
L
=
300
500
A
Circuit current while off
I
CCH
1
V
CC
=Vs typ./0.85V, R
L
=
15
25
A
R
L
=4.7k
PST596
30
50
75
"H" transport delay time
T
PLH
2
C
L
=100pF
PST597
60
100
150
ms
*
1
PST598
120
200
300
"L" transport delay time
T
PHL
2
R
L
=4.7k, C
L
=100pF,
*
2
20
s
Operating power supply voltage
V
OPL
1
R
L
=4.7k, V
OL
<
= 0.4V
0.65 0.85
V
Output current while on 1
I
OL
1
1
V
CC
=Vs min. -0.05V, R
L
=0
8
mA
Output current while on 2
I
OL
2
1
V
CC
=Vs min. -0.05V, R
L
=0
6
mA
Ta=-20~+75
C
M/R pin input H voltage
V
RESH
2.0
V
M/R pin input H current
I
RESH
V
RESH
=2.0V
10
60
A
M/R pin input low voltage
V
RESL
-0.3
0.8
V
MITSUMI
System Reset PST596~598
Measuring Circuit
[1]
[2]
Timing Chart
M/R
V
V
RES
V
V
Time
V
OUT
T
PLH
T
PLH
T
PLH
V
CC
V
S
V
S
0V
+0.4V
-0.4V
V
S
typ
V
S
typ
INPUT PULSE
Note: Thoroughly check the actual operation of the circuit, then set the manual reset when pressing the
manual switch ON to about 15s.
MITSUMI
System Reset PST596~598
Application circuits
1. Normal hard reset
Note: Connect a capacitor between IC V
CC
and GND
pins if V
CC
line impedance is high.
2. Manual reset
V
OUT
pin low for manual switch ON.
V
OUT
pin high for manual switch OFF.
Note1:
*
Mount a clamp diode if it is possible that the
M/R pin might go below -0.3V.
Note2: Thoroughly check the actual operation of the
circuit, then set the manual reset when
pressing the manual switch ON to about
15s.
Characteristics
V
CC
VS
V
OUT
V
OUT
V
S
V
S
V
CC
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