Microprocessor Voltage Monitors with Programmable Voltage Detection

Maxim's MAX8211 and MAX8212 are CMOS micropower voltage detectors that warn microprocessors (µPs) of power failures. Each contains a comparator, a 1.15V bandgap reference, and an open-drain n-channel output driver. Two external resistors are used in conjunction with the internal reference to set the trip voltage to the desired level. A hysteresis output is also included, allowing the user to apply positive feedback for noise-free output switching.

The MAX8211 provides a 7mA current-limited output sink whenever the voltage applied to the threshold pin is less than the 1.15V internal reference. In the MAX8212, a voltage greater than 1.15V at the threshold pin turns the output stage on (no current limit).

The CMOS MAX8211/MAX8212 are plug-in replacements for the bipolar ICL8211/ICL8212 in applications where the maximum supply voltage is less than 16.5V. They offer several performance advantages, including reduced supply current, a more tightly controlled bandgap reference, and more available current from the hysteresis output.

Applications

* µP Voltage Monitoring * Battery-Backup Switching * Low-Battery Detection * Overvoltage Detection * Power-Supply Fault Monitoring * Undervoltage Detection

* µP Power-Fail Warning

* Improved 2nd Source for ICL8211/ICL8212

* Low-Power CMOS Design

* 5µA Quiescent Current

* On-Board Hysteresis Output

* ±40mV Threshold Accuracy (±3.5%)

* 2.0V to 16.5V Supply-Voltage Range

* Define Output Current Limit (MAX8211)

* High Output Current Capability (MAX8212)