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UM807/821/822
μP Reset Circuits with Long Manual Reset Setup Period UM807/821/822 SOT143
General Description
The UM807/821/822 are low-power microprocessor (μP) supervisory circuits used to monitor power supplies in μP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The UM807/821/822 also provide a debounced manual reset input with long setup period. On all devices, the reset output asserts when the VCC supply voltage drops below its specified threshold. The reset output remains asserted for the reset timeout period (240ms typ) after VCC rises above the reset threshold. The reset output is one-shot pulse asserted for the reset timeout period (140ms min) when manual reset input is held low for a fixed setup timeout period. These devices ignore manual reset transitions of _l_e__s_s___t_h__a__n the fixed setup timeout period. _T__h__e____U__M__ 807 has an.