Reset chips

STMicroelectronics has announced four microprocessor reset chips that are intended for high volume, cost sensitive applications, including computers, servers, printers, fax machines, mobile and GSM phones and consumer products.

Commonly used to monitor the microprocessor supply voltage, the STM809, STM810, STM811 and STM812 circuits are designed to generate a reset signal if that voltage falls below tolerance and to provide precision monitoring of 3, 3.3 and 5 V supplies.

Each device is available with one of five nominal voltage thresholds, from 2.63 to 4.63, and also provides power-on reset when system power is first applied. The STM811 and STM812 include a manual push-button reset input which requires no additional debounce circuitry.

Offered in SOT23 and SOT143 packages, the devices' push-pull outputs provide a 140 ms reset pulse after the supply has risen above the threshold. The outputs of STM809 and STM811 are active low, while the outputs of STM810 and STM812 are active high. The reset assertion is guaranteed for a supply voltage down to 1.