WM8758CBGEFLSLASHV datasheet(52/90 Pages) WOLFSON

52 / 90 page

WM8758B

Production Data

PD, Rev 4.4, January 2012

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

Power

management

LMIXEN

Left output channel mixer enable:

0 = disabled

1= enabled

RMIXEN

Right output channel mixer enable:

0 = disabled

1 = enabled

Table 32 Left and Right Output Mixer Control

HEADPHONE OUTPUTS (LOUT1 AND ROUT1)

The headphone outputs LOUT1 and ROUT1 can drive a 16

 or 32 headphone load, either through

DC blocking capacitors, or DC-coupled to a buffered midrail reference (LOUT2 or ROUT2), saving a

capacitor (capless mode). When using capless mode, AVDD1 and AVDD2 should use the same

supply to equalize supply rejection. OUT3 and OUT4 should not be used as a buffered midrail

reference in capless mode.

Each headphone output has an analogue volume control PGA with a gain range of -57dB to +6dB as

shown in Figure 25.

In order to provide common mode rejection of ground noise on the left and right outputs, a

headphone common ground feedback option is provided. HP_COM input may be used as HPCOM

common ground feedback signal. This signal is compared to the chip internal midrail voltage and the

difference used as the reference input to the headphone output buffer amplifier, as shown in Figure

25, and in more detail in the analog internal circuit diagram.

Figure 25 Headphone Outputs LOUT1 and ROUT1

Headphone Output using DC Blocking Capacitors: with HPCOM

common mode feedback applied

DC Coupled Headphone Output: no HPCOM feedback

Figure 26 Recommended Headphone Output Configurations

WM8758CBGEFL/V Datasheet(PDF) 52 Page - Wolfson Microelectronics plc