DESCRIPTION

The DS1238 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 DS1238 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 DS1238-5

• 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