Microprocessor supervisory circuit monitors system voltage with programmable delay

15-02-2018 | Diodes Inc | Power

The PT7M3808 family of microprocessor supervisory circuits introduced from Diodes Incorporated monitors system voltages from 0.4V to 5V. With threshold accuracy from 0.5% and an adjustable delay time from 1.25ms to 10ms, these small form-factor devices enable power-on reset functionality for MPUs and other digital systems while using minimal power. Applications include desktop and notebook computers, and battery-powered portable equipment for businesses ranging from data centres to security systems.

Offered in fixed-threshold versions for standard voltage rails between 0.9V and 5V, and with an adjustable threshold version down to 0.4V, the device employs 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 5V. The delay time is adjusted from 1.25ms to 10ms by joining an external capacitor to the CT pin; a longer 20ms delay can be accomplished by disconnecting the CT pin, while a 300ms delay is plausible by connecting the CT pin to VDD with a resistor.

The device has a very low quiescent current, typically 2.8A, making it ideal for battery-powered applications. Available in SOT26 and DFN2020-6 packages, the device takes up very little board space for both new and drop-in replacement designs.

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