The CAT803, CAT809, and CAT810 are supervisory circuits that monitor power supplies in digital systems. The CAT803, CAT809, and CAT810 are direct replacements for the MAX803, MAX809 and MAX810 in applications operating over the industrial temperature range. 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 CAT803 has an open−drain RESET output (active LOW). The CAT803 requires a pull−up resistor on the reset output. The CAT809 features a push−pull RESET output (active LOW) and the CAT810 features a push−pull RESET output (active HIGH). Fast transients on the power supply are ignored and the output is guaranteed to be in the correct state at VCC levels as low as 1.0 V. The CAT803, CAT809, and CAT810 are available in both the compact 3−pin SOT−23 and SC−70 packages.