AS1922 Supervisor IC

Description

The AS1920 and AS1922 microprocessor supervisory circuits were designed to generate a reset when at least one of the three monitored supply voltages falls below its respective trip threshold.

These very-low-current (6.5µA, typ) devices maintain reset for a minimum timeout period after all supplies have stabilized. Guaranteed to be in the correct state for VCC down to 1.0V, these devices are perfect for multiple-voltage systems with low current requirements and strict monitoring requirements.

The devices are available with the following output types:

• Model Output Type Supervisory Range
• AS1920-18 Push/Pull 3.0V, 1.8V, Adjustable
• AS1922-18 Open-Drain 3.0V, 1.8V, Adjustable

All devices monitor primary and secondary factory trimmed voltages. Additionally, a third monitoring voltage can be selected via an external resistor divider.

The AS1920 has an active-low push/pull reset output, whereas the AS1922 has an active-low open-drain reset output.

The AS1920 and AS1922 are available in a 5-pin SOT23 package.

Key Features

• Simultaneous Triple-Voltage Monitoring
• 1.5% Accuracy
• 6.5µA Very-Low Supply Current
• 200ms Reset Time Delay
• Power Supply Transient Immunity
• Guaranteed Reset for VCC3 = 1V or VCC18 = 1V
• Two Reset Output Types
• Active-Low Push/Pull Reset Output (AS1920)
• Active-Low Open-Drain Reset Output (AS1922)
• 5-pin SOT23 Package

Applications

The devices are ideal for personal computers, laptops, notebooks, battery-powered systems, embedded controllers, intelligent instruments, automotive systems, critical CPU monitoring, and any multi-supply monitoring application.