AS3412 datasheet(19/84 Pages) AMSCO

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ams Datasheet

Page 19

[v1-00] 2016-Apr-06

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AS3412 − Detailed Description

Headphone Amplifier

The headphone amplifier is a true ground output using VNEG as

negative supply. It is designed to feature an output power of

2x34mW @ 32

Ω load. 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 22. With a VBAT

voltage of 1.8V, a maximum output power of 90mW can be

achieved. This is required for over- and on ear headsets with

higher output power requirements. The amplifier itself features

various input sources. The line input signal is directly connected

to the headphone amplifier. The input multiplexer supports

three different input signals which can be configured according

to the HPH_MUX register. The “Open” setting is being used to

disable the active noise cancelling function.

Figure 21:

Headphone Amplifier Single Ended

Headphone Amplifier Single Ended: 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.

QMICR

QOP1R

open

QMICL

QOP1L

open

HPR

HPL

LINL

AGND

LINR

RLIN

2kΩ

HPH_MUX

LINE_MUTE

AS3412 Datasheet(PDF) 19 Page - ams AG