General Description

The MAX703/MAX704 microprocessor (μP) supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery control functions in μP systems. These devices significantly improve system reliability and accuracy compared to that obtained with separate ICs or discrete components.

The MAX703/MAX704 are available in 8-pin DIP and SO packages and provide four functions:

   1) An active-low reset during power-up, power-down, and

      brownout conditions.

   2) Battery-backup switching for CMOS RAM, CMOS μPs,

      or other low-power logic circuitry.

   3) A 1.25V threshold detector for power-fail warning,

      low-battery detection, or for monitoring a power supply

      other than +5V.

   4) An active-low manual reset input.

The MAX703 and MAX704 differ only in their supplyvolt age monitor levels. The MAX703 generates a reset when the supply drops below 4.65V, while the MAX704 gener ates a reset below 4.40V.

Features

● Battery-Backup Power Switching

● Precision Supply-Voltage Monitor

   • 4.65V (MAX703)

   • 4.40V (MAX704)

● 200ms Reset Pulse Width

● Debounced TTL/CMOS-Compatible Manual Reset

   Input

● 200μA Quiescent Current

● 50nA Quiescent Current in Battery-Backup Mode

● Voltage Monitor for Power-Fail or Low-Battery

   Warning

● 8-Pin DIP and SO Packages

● Guaranteed RESET Assertion to VCC = 1V

Applications

   ● Computers

   ● Controllers

   ● Intelligent Instruments

   ● Critical μP Power Monitoring