DESCRIPTION
The LTC1235 provides complete power supply monitoring and battery control functions for microprocessor reset, battery backup, RAM write protection, power failure warning and watchdog timing. The LTC1235 has all the LTC695 features plus conditional battery backup and external reset control. When an out-of-tolerance power supply condition occurs, the reset outputs are forced to active states and the Chip Enable output write-protects external memory. The RESET output is guaranteed to remain logic low with VCC as low as 1V. External reset control is provided by a debounced push-button reset input.

FEATURES
■ Guaranteed Reset Assertion at VCC = 1V
■ 1.5mA Maximum Supply Current
■ Fast (35ns Max.) Onboard Gating of RAM Chip Enable Signals
■ Conditional Battery Backup Extends Battery Life
■ 4.65V Precision Voltage Monitor
■ Power OK/Reset Time Delay: 200ms
■ External Reset Control
■ Minimum External Component Count
■ 1µA Maximum Standby Current
■ Voltage Monitor for Power Fail or Low Battery Warning
■ Thermal Limiting
■ Performance Specified Over Temperature
■ All the LTC695 Features Plus Conditional Battery Backup and External Reset Control

APPLICATIONS
■ Critical µP Power Monitoring
■ Intelligent Instruments
■ Battery-Powered Computers and Controllers
■ Automotive Systems