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Notice: The information in this document is subject to change without notice

Low Power, 3.3V/3.0V µP Reset

ASM1815

rev 1.4

February 2005

Application Information

Operation - Power Monitor

The ASM1815 detects out-of-tolerance power supply

conditions. It resets a processor during power-up, power-

down and issues a reset to the system processor when the

monitored power supply voltage is below the reset threshold.

RESET signal is asserted. On power-up, RESET is kept

active (LOW) for approximatley 150ms after the power supply

voltage has reached the selected tolerance. This allows the

power supply and microprocessor to stablize before RESET

is released.

Output Conditions

The ASM1815 active LOW reset signal is valid as long as

ASM1815 uses a push-pull drive stage that can maintain a

a resistor can be connected from the reset pin (RESET) to

Ground (see Figure 3). This configuration will give a valid

both power up and down, this configuration will draw current

when the RESET is in the high state. A value of 100k

Ω

should be adequate to maintain a valid connection.

Microprocessor

RESET

RESET

ASM1815

100kΩ

RESET

Figure 1: Timing Diagram: Power-Up

RESET

Figure 2: Timing Diagram: Power-Down