User Manual

76 DS851F2
CS42L56
6.26 Gain & Bias Control (Address 1Dh)
6.26.1 PGA x Preamplifier Gain
Configures the gain of the PGA x preamp.
6.26.2 Boostx
Configures a +20 dB digital boost on ADC channel x.
6.26.3 Microphone Bias Output Level
Configures the voltage level of the microphone bias output.
6.27 PGA x MUX, Volume: PGA A (Address 1Eh) & PGA B (Address 1Fh)
6.27.1 PGA x Input Select
Selects the specified analog input signal into PGA channel x.
Note: For pseudo-differential inputs, the CODEC automatically chooses the respective pseudo-ground
(AIN1REF or AIN2REF) for each input selection.
Use the AINx_REF bits (Analog Input 1 x Reference Configuration and “Analog Input 1 x Reference Con-
figuration” on page 74) to properly configure the input channel.
76543210
PREAMPB1 PREAMPB0 PREAMPA1 PREAMPA0 BOOSTB BOOSTA BIAS_LVL1 BIAS_LVL0
PREAMPx[1:0] PGA x Preamp Gain
00 0dB
01 +10 dB
10 +20 dB
11 Reserved
BOOSTx +20 dB Boost
0 No boost applied
1 +20 dB digital boost applied
BIAS_LVL[1:0] MIC Bias Output Level
00 0.9xVA
01 0.8xVA
10 0.7xVA
11 0.6xVA
76 5 4 3 2 1 0
PGAxMUX1 PGAxMUX0 PGAxVOL5 PGAxVOL4 PGAxVOL3 PGAxVOL2 PGAxVOL1 PGAxVOL0
PGAxMUX[1:0] Selected Input to PGAx
00 AIN1x.
01 AIN2x.
10 AIN3x.
11 Reserved