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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.

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 less than the fixed setup timeout period.

The UM807 has an active-low RESET

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with open-drain output, the UM821 has an active-low

RESET

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with push-pull output, and the UM822 has an active-high RESET with push-pull output.

These devices, offered in small SOT143 package, are fully guaranteed over the extended

temperature range (-40°C to +85°C).

Applications

Features

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Set-Top Boxes

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Consumer Electronics

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DVD Players

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Cable/DSL Modems

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MP3 Players

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Industrial Equipments

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Automotive

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Medical Devices

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No External Components

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Supplies

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2μA Supply Current

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140ms Minimum Power-On Reset Pulse Width

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A: 10.08s

B: 6.72s

C: 1.68s

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Available in 3 Output Configurations:

Open-Drain Active-Low RESET

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Output(UM807);

Push-Pull Active-Low RESET

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Output(UM821)

Push-Pull Active-High RESET Output(UM822)

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4-Pin SOT143 Package

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Wide Operation Temperature: -40°C to +85°C