MITSMI PST620DDB, PST620DFT, PST621DDB, PST621DFT Datasheet

MITSUMI

System Reset (with battery back-up) PST620, 621

System Reset (with battery back-up)

Monolithic IC PST620, 621

Outline

Features

1. Low current consumption

2. Capacitors (super capacitor, large capacity chemical capacitor) are used for back-up power supply, lowering
system cost

3. Stable 1-chip microcomputer crystal oscillator rise time maintained with the built-in pulse shaver.

4. In addition to power outage detection for main power supply (+5V), there are built-in pins to detect AC power
supply and +5V power supply primary side

5. Reset signal output by back-up power supply (super capacitor, large capacity chemical capacitor) detection

Applications

1. VCR

2. Audio equipment

3. Communications equipment

4. Rice cookers, etc.

Pin Assignment

Pin Description

1432

8567

PST620

Pin No. Pin name Function

1 V

AC

Has +2.0V detection voltage to detect AC power supply and
stable power supply primary side, for quick power outage detection.

2 VCC1 +5V main power supply
3 V

CC2

Back-up power supply (back-up capacitor connected)

4 TC

Pulse width setting pin for pulse shaver
(capacitor and resistor connected)

5

RE

Reset output

6 PS

CONT

Pulse shaver ON/OFF switching High : OFF Low : ON

7 CE Chip enable signal output
8 GND GND

Package

DIP-8B (PST620DDB, PST621DDB)
SOP-8C (PST620DFT, PST621DFT)

These ICs are part of the regular series of back-up ICs, and use capacitors (super capacitor, large capacity
chemical capacitor) as back-up power supply. They control 1-chip microcomputer high-speed, low-speed,
and stand-by modes (MNI control).
These ICs also are capable of controlling data save in EPROM and other nonvolatile memories during power outage.

MITSUMI

System Reset (with battery back-up) PST620, 621

PST621

Pin No. Pin name Function

1 V

AC

Has +2.0V detection voltage to detect AC power supply and

stable power supply primary side, for quick power outage detection.

2 VCC1 +5V main power supply
3 V

CC2 Back-up power supply (back-up capacitor connected)

4 T

C

Pulse width setting pin for pulse shaver
(capacitor and resistor connected)

5 RE

---------------------------------------------------------------

Reset output

6 MODE

Switches 1-chip microcomputer mode with pulse
shaver output signal

7 CE

Chip enable signal output (power outage detection signal)

8 GND GND

Block Diagram

PST620

PST621

Absolute Maximum Ratings

(Ta=25°C)

Item Symbol Rating

Storage temperature T

STG

-

40~+125°C

Operating temperature T

OPR

-

20~+70°C

Power supply voltage V

CC max.

-

0.3~+10V

TC input input voltage V

C max. VCC1+0.3V

Allowable loss Pd 450mW