DESCRIPTION

The DS1323 Flexible Nonvolatile Controller with Lithium Battery Monitor is a CMOS circuit that solves the application problem of converting CMOS SRAMs into nonvolatile memory. Incoming power is monitored for an out-of-tolerance condition. When such a condition is detected, chip-enable outputs are inhibited to accomplish write protection and the battery is switched on to supply the SRAMs with uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery consumption. One DS1323 can support as many as four SRAMs arranged in any of three memory configurations.

FEATURES

Converts CMOS SRAM into nonvolatile memory

Unconditionally write-protects SRAM when VCC is out of tolerance

Automatically switches to battery backup 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

10% power-fail detection

Industrial temperature range of -40°C to +85°C