GENERAL DESCRIPTION
The TDA3681 is a multiple output voltage regulator with a power switch and an ignition buffer. It is intended for use in car radios with or without a microcontroller.

FEATURES
General
• Extremely low noise behaviour and good stability with very small output capacitors
• Second supply pin for regulators 3 and 4 to reduce power dissipation (e.g. via a DC-to-DC converter)
• Three VP-state controlled regulators (regulators 1, 3 and 4) and a power switch
• Regulator 2, reset and ignition buffer operational during load dump and thermal shutdown
• Combined control pin for switching regulators 1 and 3
• Separate control pins for switching regulator 4 and the power switch
• Supply voltage range from −18 to +50 V
• Low quiescent current in standby mode (when regulators 1, 3 and 4 and power switch are switched off and ignition input is low)
• Hold output (open-collector output stage) for low VP (regulators 1, 3 and 4 and power switch off)
• Hold output when one of regulators 1 and 3 and/or 4 is out of regulation
• Hold output for foldback mode of power switch and regulators 1, 3 and 4 • Hold output for load dump and temperature protection
• Reset (push-pull output stage) for regulator 2
• Adjustable reset delay time
• High supply voltage ripple rejection
• Backup capacitor for regulator 2
• One independent ignition buffer (active HIGH).