PA4101: Punk with μP Supervision

Features Precision supply voltage monitoring Reset Timeout Delay 36dB mute attenuation 2.7V to 5.5V single-supply operation ESD protected outputs Low supply current Soft Mute out for driving additional channels SOIC 14

Applications Set-top boxes Cell phones PDA’s Portable DVD players Portable MP3 players Notebook Audio Critical μP Power Monitoring

• Application Notes
• Block Diagrams
• White Papers
• Evaluation Boards
• Datasheet

General Description

The PA4101 is a low power monolithic CMOS mixed signal device. Its function is to control power supply transition noise in audio circuits and systems. It requires very few external components for its operation and works from low to medium power supply voltages of 2.7V to 5.5V. As the power supply ramps ON or OFF, the PA4101 ensures that audio inputs to succeeding amplifiers are switched to a convenient low impedance voltage rail. This causes the amplifiers to remain silent as the power supply changes state (from ON to OFF and vice versa).

Also included in the device is a digital control pin which can be used by a control device such as a micro controller or a micro- processor or any other digital controller to enable the audio mute function. This supervisory circuit provides maximum flexibility for monitoring power supplies and battery controlled functions in systems without backup batteries.

A Reset is asserted during power up, power down and brownout conditions. RESET is guaranteed down to Vcc of 1.0V.

Low line output. The early warning indicator goes low when the supply voltage drops to a value 2% higher than the reset threshold voltage
The PA4101 consumes less than 50μA of supply current while providing more than 36dB of mute attenuation at the audio lines. ESD (Human Body Model) protection circuitry on the outputs protects the PA4101 and devices further up the signal chain.

The PA4101 is available as a 14L SOIC package and is specified for operation over the -40°C to +85°C temperature range.