The CAT811 and CAT812 are µP supervisory circuits that monitor power supplies in digital systems. The CAT811 and CAT812 are direct replacements for the MAX811 and MAX812 in applications operating over the industrial temperature range; both have a manual reset input.These devices generate a reset signal, which is asserted while the power supply voltage is below a preset threshold level and for at least 140 ms after the power supply level has risen above that level. The underlying floating gate technology, Analog EEPROM used by ON Semiconductor, makes it possible to offer any custom reset threshold value. Seven industry standard threshold levels are offered to support +5.0 V, +3.3 V, +3.0 V and +2.5 V systems.The CAT811 features aRESETpush-pull output (active LOW) and the CAT812 features a RESET push-pull output (active HIGH).Fast transients on the power supply are ignored and the output is guaranteed to be in the correct state at VCClevels as low as 1.0 V.The CAT811/812 are fully specified over the industrial temperature range (-40°C to 85°C) and are available in a compact 4-pin SOT143 package.