Outline

These ICs were developed for D-RAM and dummy S-RAM battery back-up. D-RAM and dummy S-RAM power supplies differ from that of S-RAMs because 5V or 3.3V of power supply is required even during battery back-up. Therefore, these ICs provide voltage from a stable power supply during both normal operation and back-up. Also, the internal stable power supply switches automatically to battery back-up if the main power supply voltage goes down for any reason.

Features

1. Battery back-up

MM1025

Current consumption 600µA typ.

Input/output voltage difference IL=40mA 0.25V typ.

Output current 40mA max.

MM1174

Current consumption 300µA typ.

Input/output voltage difference IL=40mA 0.13V typ.

Output current 40mA max.

2. Normal operation

MM1025

Input/output voltage difference IL=80mA (built-in transistor) 0.29V typ.

Output current VCC=6V 80mA typ.

External transistor drive current VCC= 6V 15mA typ.

Current consumption 900µA max.

MM1174 (for external transistor)

Input/output voltage difference IL=200mA 0.13V typ.

Output current Depends on external transistor

External transistor drive current (no built-in TR) VCC=3.6V 10mA typ.

Current consumption 500µA max.

3. Switching voltage from VCC to Battery VCC=High Low

MM1025 4.9V typ.

MM1174 3.25V typ.

4. VCC-Battery forced switching and detection voltage adjustment possible

Applications

1. Memory cards (D-RAM cards, other)

2. PCs, word processors and other equipment with D-RAMs

3. Fax machines, photocopiers and other office equipment with D-RAMs