General Description

The AS1923 microprocessor supervisory circuit was designed to monitor up to four system supply voltages without the need for external components, and asserts a single reset if any of the monitored supply voltages drops below its reset threshold.

The AS1923 features an active-low reset output that is asserted when any of the 4 monitored voltages are below their respective reset threshold. The reset output is open-drain with a weak internal pullup (10µA) to IN2. Reset remains low for a specified reset timeout period (120ms min) after all voltages have stabilized. The output is valid as long as the IN1 or IN2 input voltage remains >1V.

Key Features

■ Simultaneous Quad-Voltage Monitoring

■ Precision Factory-Trimmed Reset Threshold Options: +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V

■ User-Adjustable Voltage Monitoring Threshold Options

■ Low Supply Current: 55µA

■ Open-Drain – AS1923A

■ 10µA Current Source Pullup – AS1923B

■ Reset Timeout Period: 120ms

■ RESET Valid to IN1 = 1V or IN2 = 1V

■ Immune to Fast INx Transients

■ External Components not Required

■ Guaranteed Performance: Operating Temperature Range = -40 to +85ºC

■ 6-pin SOT23 Package

Applications

The device is ideal for portable and battery-powered systems, embedded controllers, intelligent instruments, automotive systems, critical CPU monitoring, and any multi-supply application.