Microprocessor Supervisory Circuit from Diodes Monitors System Voltage with Programmable Delay

Diodes announced the PT7M3808 family of microprocessor supervisory circuits. These devices monitor system voltages from 0.4V to 5.0V, and feature threshold accuracy from 0.5% and an adjustable delay time from 1.25ms to 10s; this allows these small form-factor devices to enable power-on reset functionality for microprocessor and other digital systems while also consuming minimal power. Applications include notebook and desktop computers, and battery-powered portable equipment for markets ranging from data centers to security systems.

Offered in fixed-threshold versions for standard voltage rails between 0.9V and 5.0V, and with an adjustable threshold version down to 0.4V, the PT7M3808 uses a precision reference to provide a 0.5% negative-going input threshold accuracy when monitoring voltages up to 3.3V and 1% accuracy at voltages from 3.3V to 5.0V. The delay time is adjusted from 1.25ms to 10s by connecting an external capacitor to the CT pin; a 20ms delay can be achieved by disconnecting the CT pin, while a 300ms delay is possible by connecting the CT pin to Vdd with a resistor.

The PT7M3808 has a very low quiescent current, typically 2.8µA, making it well-suited for battery-powered applications.