Nonvolatile Controller 20-Pin SOIC W

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 V_cc 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%