Nonvolatile Controller X 8 Chip

The DS1211 Nonvolatile Controller x8 Chip performs five circuit functions required to render standard CMOS RAM nonvolatile:

* Monitor Vcc using a precise comparator that detects power-fail and inhibits chip-enable

* Monitor battery status and warn the processor of low status

* Switch power between a battery and Vcc, whichever is greater

* Write-protect data

* Provide for automatically switching between two batteries

Power-fail detection occurs in the range of 4.75V to 4.5V with the tolerance Pin 3 grounded. If Pin 3 in connected to Vcco, then power-fail detection occurs in the range of 4.5 volts to 4.25 volts.

By combining the DS1211 nonvolatile controller/decoder chip and lithium batteries, nonvolatile RAM operation can be achieved for up to eight CMOS memories.

* Controller circuitry with monitoring and logic functions to make CMOS RAM nonvolatile

* Controls up to 8 memories

* Monitors Vcc and write-protects when out of tolerance

* Consumes less than 100nA battery current

* Tests battery condition on power-up

* Supports redundant batteries

* Thermal operating ranges:

* DS1211: 0°C to +70°C

* DS1211-IND: -40° to +85°C

* Voltage/tolerances: 5V ±5% or ±10%