SLAS509G April 2006 – July 2021 TLV320AIC3106
PRODUCTION DATA
Maximum PGA gain applicable allows the user to restrict the maximum PGA gain that can be applied by the AGC algorithm. This can be used for limiting PGA gain in situations where environmental noise is greater than programmed noise threshold. It can be programmed from 0 dB to 59.5 dB in steps of 0.5 dB.
Note that the time constants here are correct when the ADC is not in double-rate audio mode. The time constants are achieved using the fS(ref) value programmed in the control registers. However, if the fS(ref) is set in the registers to, for example, 48 kHz, but the actual audio clock or PLL programming actually results in a different fS(ref) in practice, then the time constants would not be correct.
The actual AGC decay time maximum is based on a counter length, so the maximum decay time scales with the clock set up that is used. Table 10-2 shows the relationship of the NADC ratio to the maximum time available for the AGC decay. In practice, these maximum times are extremely long for audio applications and should not limit any practical AGC decay time that is needed by the system.