Maxim Integrated DS1231-50

Description
The DS1231 Power Monitor Chip is a precise temperature-compensated reference circuit that provides an orderly shutdown and automatic restart of a processor-based system. It monitors high voltage inputs to power supply regulators to generate a warning signal of an impending power failure well before regulated DC voltages go out of specification. The time for processor shutdown is directly proportional to the available hold-up time of the power supply. Just before the hold-up time is exhausted, the Power Monitor unconditionally halts the processor to prevent spurious cycles by enabling Reset as Vcc falls below a selectable 5 or 10 percent threshold. When power returns, the processor is held inactive until well after power conditions have stabilized, safeguarding any nonvolatile memory in the system from inadvertent data changes.

Features
Warns processor of an impending power failure
Provides time for an orderly shutdown
Prevents processor from destroying nonvolatile memory during power transients
Automatically restarts processor after power is restored
Suitable for linear or switching power supplies
Accurate 5% or 10% Vcc monitoring
Replaces power-up reset circuitry
No external capacitors required
Optional 16-pin SOIC surface mount package

Applications
Processor-based systems
Power supply monitoring
Power failure detection
Nonvolatile memory protection
System reset