AS3435 datasheet(29/102 Pages) AMSCO

29 / 102 page

ams Datasheet, Confidential: 2014-Jun-13 [v1-30]

AS3415/AS3435 – 29

Detaile d Desc rip t ion

Headphone Amplifier

The headphone amplifier is a true ground output using VNEG as

negative supply. It is designed to provide the audio signal with

2x34mW @ 32

Ω. For higher output requirements, the

headphone amplifier is also capable of operating in bridged

mode. In this mode the left output is carrying the inverted

signal of the right output shown in Figure 30. With a VBAT

voltage of 1.8V, a maximum output power of 120mW can be

achieved in this mode. This is especially required for over ear

headsets with hybrid ANC topology or any other headset with

high output power requirements. The amplifier itself features

various input sources. The line input signal is directly connected

to the headphone amplifier. In case the application requires

more complex music filtering the line input connection can be

disabled and the mixer inputs MIXR and MIXL can be used to

feed the music signal to the headphone amplifier. The mixer

inputs have a 6kΩ input resistance which gives a typical gain of

6dB with the internal 12kΩ feedback resistor of the headphone

amplifier. The input multiplexer supports four different input

signals which can be configured according to complexity of the

ANC filter.

Figure 30:

Headphone Amplifier Single Ended

Headphone Amplifier: This figure shows the block diagram of the headphone amplifier including the integrated

music bypass switches as well as the summation input of the amplifier in single ended configuration.

AS3435 Datasheet(PDF) 29 Page - ams AG