wm8775 Wolfson Microelectronics plc, wm8775 Datasheet - Page 33

• Manufacturer Part Number: wm8775
• Description: 24-bit, 96khz Adc With 4 Channel I/p Multiplexer
• Manufacturer: Wolfson Microelectronics plc

Production Data
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ALC Control 1
ALC Control 2
ALC Control 3
Attenuation
Attenuation
R16 (10h)
R17 (11h)
R18 (12h)
R14 (0Eh)
R15 (0Fh)
0010000
0010001
0010010
0001110
0001111
ADCR
ADCL
7:0
7:0
3:0
6:4
8:7
3:0
3:0
7:4
8
8
7
8
MAXGAIN[2:0]
LCSEL[1:0]
RAG[7:0]
DCY[3:0]
LAG[7:0]
ATK[3:0]
LCT[3:0]
HLD[3:0]
ALCZC
ZCRA
ZCLA
LCEN
111 (+24dB)
11001111
11001111
cross off)
(268ms/
(24ms)
9.6ms)
0 (zero
(-5dB)
(0dB)
(0dB)
(0ms)
0010
0011
1011
0000
00
0
0
0
Attenuation data for left channel ADC gain in 0.5dB steps
Left channel ADC zero cross enable:
Attenuation data for right channel ADC gain in 0.5dB steps
Right channel ADC zero cross enable:
Limiter Threshold/ALC target level in 1dB steps.
0000: -16dB FS
0001: -15dB FS
…
1101: -3dB FS
1110: -2dB FS
1111: -1dB FS
Set Maximum Gain of PGA
111 : +24dB
110 : +20dB
….(-4dB steps)
010 : +4dB
001 : 0dB
000 : 0dB
ALC/Limiter function select
00 = Limiter
01 = ALC Right channel only
10 = ALC Left channel only
11 = ALC Stereo (PGA registers unused)
ALC hold time before gain is increased.
0000: 0ms
0001: 2.67ms
0010: 5.33ms
… (time doubles with every step)
1111: 43.691s
ALC uses zero cross detection circuit.
Enable Gain control circuit.
0 = Disable
1 = Enable
ALC/Limiter attack (gain ramp-down) time
ALC mode
0000: 8.4ms
0001: 16.8ms
0010: 33.6ms…
(time doubles with every step)
1010 or higher: 8.6s
ALC/Limiter decay (gain ramp up) time
ALC mode
0000: 33.5ms
0001: 67.2ms
0010: 134.4ms ….(time
doubles for every step)
1010 or higher: 34.3ms
0: Zero cross disabled
1: Zero cross enabled
0: Zero cross disabled
1: Zero cross enabled
Limiter Mode
0000: 250us
0001: 500us…
0010: 1ms
(time doubles with every step)
1010 or higher: 256ms
Limiter mode
0000: 1.2ms
0001: 2.4ms
0010: 4.8ms ….(time doubles
for every step)
1010 or higher: 1.2288s
PD, Rev 4.4, October 2008
WM8775
33