WM8980CGEFLSLASHV datasheet(23/123 Pages) WOLFSON

23 / 123 page

Pre-Production

WM8980

PP, Rev 3.8, May 2012

Stereo Camcorder; The provision of two stereo microphone preamplifiers, allows support for both

internal and external microphones. All drivers for speaker, headphone and line output connections are

integrated. The selectable ‘application filters’ after the ADC provide for features such as ‘wind noise’

reduction, or mechanical noise reducing filters. The integrated video buffer allows direct connection

to a TV or VCR for both video and audio (via line outputs).

Stereo Digital still camera recording; Support for digital stereo video with audio recording is similar to

the camcorder case. But additionally if the DSC supports MP3 playback, and perhaps recording, the

ability of the ADCs to support full 48ks/s high quality stereo recording increases device flexibility. The

integrated video buffer allows direct connection to the TV for display of moving and still images.

Mono Digital still camera; Full control over device functionality, and power control is provided,

allowing for the case of mono DSC recording, when half of the ADC and mic and line functionality

may be disabled to save power. In the mono case, the single ADC channel of audio data is sent out

over the Left channel of the audio interface. In the case where DSP mode is used, and mono data is

being sent, only the signal channel of mono data is sent. The integrated video buffer allows direct

connection to the TV for display of moving and still images.

AUXILIARY ANALOGUE INPUTS

An analogue stereo FM tuner or other auxiliary analogue input can be connected to the Line inputs of

WM8980, and the stereo signal listened to via headphones, or recorded, simultaneously if required.

INPUT SIGNAL PATH

The WM8980 has a number of flexible analogue inputs. There are two input channels, Left and

Right, each of which consists of an input PGA stage followed by a boost/mix stage which drives into

the hi-fi ADC. Each input path has three input pins which can be configured in a variety of ways to

accommodate single-ended, differential or dual differential microphones. There are two auxiliary

input pins which can be fed into to the input boost/mix stage as well as driving into the output path. A

bypass path exists from the output of the boost/mix stage into the output left/right mixers.

MICROPHONE INPUTS

The WM8980 can accommodate a variety of microphone configurations including single ended and

differential inputs. The inputs to the left differential input PGA are LIN, LIP and L2. The inputs to the

right differential input PGA are RIN, RIP and R2.

In single-ended microphone input configuration the microphone signal should be input to LIN or RIN

and the internal NOR gate configured to clamp the non-inverting input of the input PGA to VMID.

In differential mode the larger signal should be input to LIP or RIP and the smaller (e.g. noisy ground

connection) should be input to LIN or RIN.

Figure 9 Microphone Input PGA Circuit

WM8980CGEFL/V Datasheet(PDF) 23 Page - Wolfson Microelectronics plc