DESCRIPTION

· The LTC690 family provides complete power supply monitoring and battery control functions for microprocessor systems.

· It includes features like microprocessor reset, battery backup, CMOS RAM write protection, power failure warning, and watchdog timing.

· The family uses a precise internal voltage reference and comparator circuit to monitor the power supply line.

· It ensures reset outputs are forced to active states during out-of-tolerance conditions and unconditionally write-protects external memory.

· The LTC690 family powers active CMOS RAMs with a charge-pumped NMOS power switch for low dropout and low supply current.

· It provides an internal comparator for early warning of power failure and an internal watchdog timer.

FEATURES

· Guaranteed reset assertion at VCC = 1V.

· Maximum supply current of 1.5mA.

· Fast onboard gating of RAM chip enable signals (35ns max).

· Available in SO-8 and S16 packaging.

· Precision voltage monitor at 4.65V.

· Power OK/Reset time delay options: 50ms, 200ms, or adjustable.

· Minimum external component count.

· Maximum standby current of 1µA.

· Voltage monitor for power-fail or low battery warning.

· Thermal limiting and performance specified over temperature.

· Superior upgrade for MAX690 family.

APPLICATIONS

· Critical µP power monitoring.

· Intelligent instruments.

· Battery-powered computers and controllers.

· Automotive systems.