WM8961 datasheet(22/116 Pages) WOLFSON

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WM8961

Pre-Production

PP, August 2009, Rev 3.1

INPUT SIGNAL PATH

The WM8961 has a flexible stereo analogue input channel which can be configured as line inputs or

single-ended microphone inputs. The input signal path consists of an input volume control using a

Programmable Gain Amplifier (PGA), followed by an input boost stage. The output of the boost stage

drives a hi-fi stereo ADC. This is shown in Figure 12

Figure 12 Analogue Input Stage

The input PGAs and boost stage are enabled by the AINL and AINR register bits.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R25 (19h)

Power

Management

(1)

AINL

Left channel input PGA and boost

stage enable

0 = PGA disabled, boost disabled

1 = PGA enabled boost enabled

AINR

Right channel input PGA and boost

stage enable

0 = PGA disabled, boost disabled

1 = PGA enabled boost enabled

Table 4 Input PGA and Boost Enable Register Settings

INPUT PGA VOLUME CONTROLS

The gain of the microphone PGAs can be manually configured, or automatically controlled using the

ALC / Limiter. (Refer to section headed Automatic Level Control for more details).

The input PGA stage provide a general volume control for the LINPUT and RINPUT microphone

inputs and have a gain range from -23.25dB to +24dB in 0.75dB steps. The gain of the PGAs is

controlled by the register bits LINVOL[5:0] and RINVOL[5:0].

WM8961 Datasheet(PDF) 22 Page - Wolfson Microelectronics plc