AS1908 Supervisor IC

Description

The AS1907/AS1908/AS1909 microprocessor supervisory circuits are ideal for monitoring the supply voltage of digital systems and microprocessors.

The devices are designed to initiate a reset if the supply voltage goes below a predefined threshold. The duration of the reset is either 1.5, 30, or 150ms (typ) after the supply voltage has risen above the pre-set threshold.

The devices are available as the following standard products:

The reset thresholds are factory-set between 1.6 and 2.5V in steps of approximately 100mV.

The devices exhibit excellent reliability, and can reduce system costs by eliminating the need for external components. The extremely low current consumption makes the devices ideal for use in portable applications.

The integrated reset comparator was specifically designed to ignore fast transients on VCC.

The devices are available in a 3-pin SOT23 package.

Key Features

• 3 Output Types
  • Push/Pull RESETN (AS1907)
  • Push/Pull RESET (AS1908)
  • Open-Drain RESETN (AS1909)
• Reset Threshold Range: 1.6V to 2.5V (~100mV increments)
• RESET/RESETN:
  • Valid to VCC = 0.7V (AS1907 and AS1908)
  • Valid to VCC = 1.0V (AS1909)
• Reset Pulse Widths: 1, 20, and 100ms
• Supply Voltage Range: +0.7V to +3.6V
• Supply Current Range: 2.6μA to 7.0μA
• Power Supply Transient Immunity
• Requires No External Components
• Operating Temperature Range: -40ºC to +125ºC
• 3-pin SOT23 Package

Applications

The devices are ideal for use in cordless and mobile phones, MP3 players, CD and DVD players, PDAs, handheld computers, digital cameras, hard drives, and any other application where power supply supervisory control is required.

Block diagram for AS1908 Supervisor IC