STMICROELECTRONICS, represented by Braemac , has released four industry standard microprocessor reset chips intended for high volume, cost sensitive microprocessor-based applications. These include computers, servers, printers, fax machines, cellular and GSM phones and consumer products.
Commonly used to monitor the microprocessor supply voltage, the STM809, STM810, STM811 and STM812 reset circuits are designed to generate a reset signal if that voltage falls below tolerance and to provide precision monitoring of 3V, 3.3V and 5V supply voltages.
Each device is available with one of five nominal voltage thresholds, from 2.63V to 4.63V, 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 products' push-pull outputs provide a 140ms 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 1V.
The STM809 and STM810 are 3-pin devices in SOT23-3 packages, while the 4-pin STM811 and STM812 use the SOT143-4 package. All are specified for operation over the -40°C to 85°C industrial temperature range, and are supplied on tape and reel.