WM8991 datasheet(41/174 Pages) WOLFSON

41 / 174 page

Pre-Production

WM8991

PP, May 2008, Rev 3.1

LINE INPUTS

All eight analogue input pins may be configured as line inputs. Various signal paths exist to provide

flexibility, high performance and low power consumption for different usage modes.

LIN1 and RIN1 can operate as line inputs to the Input PGAs LIN12 and RIN12 to provide high gain if

required for small input signals.

LIN2 and RIN2 can operate as line inputs directly to the input mixers or to the speaker output mixer.

Direct routing to the speaker output minimises power consumption by reducing the number of active

amplifiers in the signal path.

LIN3 and RIN3 can operate as line inputs to the Input PGAs or as a line input directly to either of the

output mixers LOMIX and ROMIX.

LIN1+LIN3 and RIN1+RIN3 can also be used as fully balanced differential inputs via the Input PGAs

to one of the input mixers. (Note that these inputs have matched input impedances.)

LIN4/RXN and RIN4/RXP can operate as line inputs directly to the outputs OUT3 and OUT4,

providing an ultra-low power stereo or mono differential signal path (e.g. from an external voice

CODEC) to an ear speaker. LIN4/RXN and RIN4/RXP can also operate as a mono differential input

to the ADC input signal path and output mixer stages.

Figure 19 LIN1 or RIN1 as Line Inputs

Figure 20 LIN2 or RIN2 as Line Inputs

Figure 21 LIN3 or RIN3 as Line Inputs

Figure 22 Fully Balanced Differential Input

WM8991 Datasheet(PDF) 41 Page - Wolfson Microelectronics plc