Datasheet
Target
Level
Input
Signal
Output
Signal
AGC
Gain
Attack
Time
Decay Time
TLV320ADC3101
SLAS553A – NOVEMBER 2008 – REVISED SEPTEMBER 2009 ......................................................................................................................................
www.ti.com
Table 3. AGC Parameter Settings (continued)
Control Register Control Register
Function Bit
Left ADC Right ADC
Debounce time (noise) Page 0 / register 91 Page 0 / register 99 D4 – D0
Debounce time (signal) Page 0 / register 92 Page 0 / register 100 D3 – D0
Gain applied by AGC Page 0 / register 93 Page 0 / register 101 D7 – D0 (read-only)
AGC noise-threshold flag Page 0 / register 45 (sticky flag), Page 0 / register 45 (sticky flag), D6 – D5 (read-only)
Page 0 / register 47 (non-sticky flag) Page 0 / register 47 (non-sticky
flag)
AGC saturation flag Page 0 / register 36 (sticky flag) Page 0 / register 36 (sticky flag) D5, D1 (read-only)
ADC saturation flag Page 0 / register 42 (sticky flag), Page 0 / register 42 (sticky flag), D3 – D2 (read-only)
Page 0 / register 43 (non-sticky flag) Page 0 / register 43 (non-sticky
flag)
Figure 32. AGC Characteristics
The TLV320ADC3101 includes three analog audio input pins, which can be configured as one fully-differential
pair and one single-ended input, or as three single-ended audio inputs. These pins connect through series
resistors and switches to the virtual ground terminals of two fully differential operational amplifiers (one per
ADC/PGA channel). By selecting to turn on only one set of switches per operational amplifier at a time, the inputs
can be effectively multiplexed to each ADC PGA channel.
By selecting to turn on multiple sets of switches per operational amplifier at a time, mixing can also be achieved.
Mixing of multiple inputs can easily lead to PGA outputs that exceed the range of the internal operational
amplifiers, resulting in saturation and clipping of the mixed output signal. Whenever mixing is being implemented,
the user should take adequate precautions to avoid such a saturation case from occurring. In general, the mixed
signal should not exceed 2 V
pp
(single-ended) or 4 V
pp
(differential).
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