General Description

The MAX690A/MAX692A/MAX802L/MAX802M/MAX805L reduce the complexity and number of components required for power-supply monitoring and battery-control functions in microprocessor (µP) systems. They significantly improve system reliability and accuracy compared to separate ICs or discrete components.

These parts provide four functions:

1) A reset output during power-up, power-down, and brownout conditions.

2) Battery-backup switching for CMOS RAM, CMOS µP, or other low-power logic.

3) A reset pulse if the optional watchdog timer has not been toggled within 1.6sec.

4) A 1.25V threshold detector for power-fail warning or low-battery detection, or to monitor a power supply other than +5V.

The parts differ in their reset-voltage threshold levels and reset outputs. The MAX690A/MAX802L/MAX805L generate a reset pulse when the supply voltage drops below 4.65V, and the MAX692A/MAX802M generate a reset below 4.40V. The MAX802L/MAX802M guaran tee power-fail accuracies to ±2. The MAX805L is the same as the MAX690A except that RESET is provided instead of RESET.

All parts are available in 8-pin DIP and SO packages. The MAX690A/MAX802L are pin compatible with the MAX690 and MAX694. The MAX692A/MAX802M are pin compatible with the MAX692.

Features

♦ Precision Supply-Voltage Monitor:

   4.65V for MAX690A/MAX802L/MAX805L

   4.40V for MAX692A/MAX802M

♦ Reset Time Delay – 200ms

♦ Watchdog Timer – 1.6sec Timeout

♦ Battery-Backup Power Switching

♦ 200µA Quiescent Supply Current

♦ 50nA Quiescent Supply Current in Battery Backup Mode

♦ Voltage Monitor for Power-Fail or Low-Battery Warning

♦ Power-Fail Accuracy Guaranteed to ±2 (MAX802L/M)

♦ Guaranteed RESET Assertion to VCC = 1V

♦ 8-Pin SO and DIP Packages

Applications

   Battery-Powered Computers and Controllers

   Intelligent Instruments

   Automotive Systems

   Critical µP Power Monitoring