The UM803 is a microprocessor (μP) supervisory circuit used to monitor the power supplies in μP and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V or +2.5V powered circuits.
The circuit performs a single function: it asserts a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available.
The UM803 has an open-drain output stage. The UM803’s open-drain RESET_____________ output requires a pull-up resistor that can be connected to a voltage higher than VCC. The UM803 has an active-low RESET_____________ output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V.
Low supply current makes the UM803 ideal for use in portable equipment. The UM803 is available in a 3-pin SOT323 and SOT23 package. UM803LP
UM803MP
UM803JP
UM803TP
UM803SP
UM803RP
UM803ZP
UM803LS
UM803MS
UM803JS
UM803TS
UM803SS
UM803RS
UM803ZS
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