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