DESCRIPTION
The DS1211 Nonvolatile Controller x 8 Chip is a CMOS circuit which solves the application problem of converting CMOS RAMs into nonvolatile memories. Incoming power is monitored for an out-oftolerance condition. When such a condition is detected, the chip enables are inhibited to accomplish write protection and the battery is switched on to supply RAMs with uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery consumption.

FEATURES
■ Converts full CMOS RAMs into nonvolatile memories
■ Unconditionally write protects when VCC is out of tolerance
■ Automatically switches to battery when power-fail occurs
■ 3 to 8 decoder provides control for up to eight 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 20-pin SOIC surface mount package
■ Optional industrial temperature range of -40°C to +85°C