The TS809/810/809R/810R are microprocessor (P) supervisory circuit used to monitor the power supplies in P and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V powered circuits. These circuits perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 240ms(typ) after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The TS809/810/809R/810R have push pull outputs. The TS809/809R have an active low RESET output, while the TS810/810R has an active high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the output guaranteed to be in the correct logic state for VCC down to 1V. Low supply correct makes the TS809/810/809R/810R ideal for use in portable equipment. The TS809/810/809R/810R is available in a 3-pin SOT-23 package.