Datasheet

ADAU1761
Rev. C | Page 60 of 92
R11: ALC Control 0, 16,401 (0x4011)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
PGASLEW[1:0] ALCMAX[2:0] ALCSEL[2:0]
Table 45. ALC Control 0 Register
Bits Bit Name Description
[7:6] PGASLEW[1:0]
PGA volume slew time when the ALC is off. The slew time is the period of time that a volume increase or decrease
takes to ramp up or ramp down to the target volume set in Register R8 (left differential input volume control)
and Register R9 (right differential input volume control).
Setting Slew Time
00 24 ms (default)
01 48 ms
10
96 ms
11
Off
[5:3] ALCMAX[2:0]
The maximum ALC gain sets a limit to the amount of gain that the ALC can provide to the input signal. This
protects small signals from excessive amplification.
Setting Maximum ALC Gain
000 −12 dB (default)
001 −6 dB
010
0 dB
011
6 dB
100
12 dB
101
18 dB
110
24 dB
111
30 dB
[2:0] ALCSEL[2:0]
ALC select. These bits set the channels that are controlled by the ALC. When set to right only, the ALC responds
only to the right channel input and controls the gain of the right PGA amplifier only. When set to left only, the
ALC responds only to the left channel input and controls the gain of the left PGA amplifier only. When set to
stereo, the ALC responds to the greater of the left or right channel and controls the gain of both the left and
right PGA amplifiers. DSP control allows the PGA gain to be set within the DSP or from external GPIO inputs.
These bits must be off if manual control of the volume is desired.
Setting Channels
000 Off (default)
001 Right only
010
Left only
011
Stereo
100
DSP control
101
Reserved
110
Reserved
111 Reserved