3.0V/3.3V Microprocessor Supervisory Circuits

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

These devices are designed for use in systems powered by 3.0V or 3.3V supplies. See the selector guide in the back of this data sheet for similar devices designed for 5V systems. The suffixes denote different reset threshold voltages: 3.075V (T), 2.925V (S), and 2.625V (R) (see Reset Threshold section in the Detailed Description). All these parts are available in 8-pin DIP and SO packages. Functions offered in this series are as follows:

Part

Active-Low Reset

Active-High Reset

Watchdog Input

Manual Reset Input

Backup-Battery Switch

Power-Fail Threshold Accuracy

Power-Fail Comparator

Reset Window

MAX690

√

√

√

±4%

√

±75mV

MAX704

√

√

√

±4%

√

±75mV

MAX802

√

√

√

±2%

√

±2%

MAX804

√

√

√

±2%

√

±2%

MAX805

√

√

√

±4%

√

±75mV

MAX806

√

√

√

±2%

√

±2%

Applications

* Battery-Powered Computers/Controllers * Critical µP Monitoring * Embedded Controllers * Intelligent Instruments * Portable Equipment

* Active-Low RESET and RESET Outputs

* Manual Reset Input

* Precision Supply-Voltage Monitor

* 200ms Reset Time Delay

* Watchdog Timer (1.6sec timeout)

* Battery-Backup Power Switching-Battery Can Exceed VCC in Normal Operation

* 40µA VCC Supply Current

* 1µA Battery Supply Current

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

* Guaranteed Active-Low RESET Assertion to VCC = 1V

* 8-Pin DIP and SO Packages