Low-Cost, µP Supervisory Circuits

The MAX705–MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.

The MAX705/MAX706/MAX813L provide four functions:

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

* An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.

* A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.

* An active-low manual-reset input.

The MAX707/MAX708 are the same as the MAX705/MAX706, except an active-high reset is substituted for the watchdog timer. The MAX813L is the same as the MAX705, except RESET is provided instead of active-low RESET.

Two supply-voltage monitor levels are available: The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX® packages. Applications

* Computers * Controllers * Critical µP Power Monitoring * Intelligent Instruments

* Supervisory-Function Integration Significantly Improves System Reliability While Reducing Board Space

* µMAX Package

* Guaranteed Active Low RESET Valid at VCC = 1V

* 200ms Reset Pulse Width

* Debounced TTL/CMOS-Compatible Manual-Reset Input

* Active-High Reset Output (MAX707/MAX708/MAX813L)

* Precision-Supply Voltage Monitor

* 4.65V (MAX705/MAX707/MAX813L)

* 4.40V (MAX706/MAX708)

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