DESCRIPTION

The DS1212 Nonvolatile Controller x16 Chip is a CMOS circuit that solves the application problem of converting CMOS RAMs into nonvolatile memories. Incoming power is monitored for an out-of tolerance condition. When such a condition is detected, the chip enables are inhibited to accomplish write protection and the battery is switched on to supply the RAMs with uninterrupted power. Special circuitry uses a low-leakage CMOS process that affords precise voltage detection at extremely low battery consumption.

By combining the DS1212 Nonvolatile Controller chip and lithium batteries, nonvolatile RAM operation can be achieved for up to 16 CMOS memories.

FEATURES

■ Converts full CMOS RAM into nonvolatile memory

■ Unconditionally write protects when VCC is out of tolerance

■ Automatically switches to battery when power-fail occurs

■ 4 to 16 decoder provides control for up to 16 CMOS RAMs

■ Consumes less than 100 nA of battery current

■ Tests battery condition on power-up

■ Provides for redundant batteries

■ Power fail signal can be used to interrupt processor on power failure

■ Optional 5 or 10 power-fail detection

■ Optional 28-pin PLCC surface mount package

■ Optional industrial temperature range of -40°C to +85°C