NAU8812EVB Nuvoton Technology Corporation of America, NAU8812EVB Datasheet - Page 30

• Manufacturer Part Number: NAU8812EVB
• Description: BOARD EVAL FOR NAU8812
• Manufacturer: Nuvoton Technology Corporation of America
• Series: emPowerAudio™r

Specifications of NAU8812EVB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Peak Limiter mode is selected when ALCM[8] address (0x22) is set to HIGH and the ALC is enabled by setting
ALCEN[8] address (0x20). In limiter mode, the PGA gain is constrained to be less than or equal to the gain setting at
the time the limiter mode is enabled. In addition, attack and decay times are faster in limiter mode than in normal
mode as indicated by the different lookup tables for these parameters for limiter mode. The following waveform
illustrates the behavior of the ALC in Limiter mode in response to changes in various ALC parameters.
When the input signal exceeds 87.5% of full scale, the ALC block ramps down the PGA gain at the maximum attack
rate (ALCATK=0000) regardless of the mode and attack rate settings until the ADC output level has been reduced
below the threshold. This limits ADC clipping if there is a sudden increase in the input signal level.
emPowerAudio
Datasheet Revision 2.0
12.4.2. Peak Limiter Mode
™
PGA Input
PGA Output
PGA Gain
Output
Hold Delay
PGA Gain
Enabled
PGA Input
PGA
Change
Limiter
Figure 14: ALC Limiter Mode Operations
Figure 13: ALC Hold Time
Page 30 of 109
NAU8812
January 2011