DESCRIPTION

The DS1238A MicroManager provides all the necessary functions for power supply monitoring, reset control, and memory backup in microprocessor-based systems. A precise internal voltage reference and comparator circuit monitor power supply status. When an out-of-tolerance condition occurs, the microprocessor reset and power-fail outputs are forced active, and static RAM control unconditionally write protects external memory. The DS1238A also provides early warning detection of a user-defined threshold by driving a non-maskable interrupt.

FEATURES

◾ Holds microprocessor in check during power transients

◾ Halts and restarts an out-of-control microprocessor

◾ Warns microprocessor of an impending power failure

◾ Converts CMOS SRAM into nonvolatile memory

◾ Unconditionally write protects memory when power supply is out of tolerance

◾ Delays write protection until completion of the current memory cycle

◾ Consumes less than 200 nA of battery current

◾ Controls external power switch for high current applications

◾ Debounces pushbutton reset

◾ Accurate 10 power supply monitoring

◾ Optional 5 power supply monitoring designated DS1238A-5

◾ Provides orderly shutdown in microprocessor applications

◾ Pin-for-pin compatible with MAX691

◾ Standard 16-pin DIP or space-saving 16-pin SOIC

◾ Optional industrial temperature range -40°C to +85°C