DESCRIPTION

The DS1321 Flexible Nonvolatile Controller with Lithium Battery Monitor is a CMOS circuit which solves the application problem of converting CMOS SRAMs into nonvolatile memory. Incoming power is monitored for an out-of-tolerance condition.

FEATURES

■ Converts CMOS SRAM into nonvolatile

memory

■ Unconditionally write-protects SRAM when

VCC is out of tolerance

■ Automatically switches to battery backup

supply when VCC power failure occurs

■ Flexible memory organization

- Mode 0: 4 banks with 1 SRAM each

- Mode 1: 2 banks with 2 SRAMs each

- Mode 2: 1 bank with 4 SRAMs each

■ Monitors voltage of a lithium cell and

provides advanced warning of impending

battery failure

■ Signals low-battery condition on active low

Battery Warning output signal

■ Resets processor when power failure occurs

and holds processor in reset during system

power-up

■ Optional 5 or 10 power-fail detection

■ 16-pin DIP, 16-pin SOIC and 20-pin TSSOP

packages

■ Industrial temperature range of -40°C to

+85°C