WM8976 datasheet(10/108 Pages) WOLFSON

10 / 108 page

WM8976

Pre-Production

PP Rev 3.0 April 2006

TERMINOLOGY

Input level to LIP is limited to a maximum of -3dB or THD+N performance will be reduced.

Note when BEEP path is not enabled then AUXL and AUXR have the same input impedances.

Hold Time is the length of time between a signal detected being too quiet and beginning to ramp up the gain. It does

not apply to ramping down the gain when the signal is too loud, which happens without a delay.

Ramp-up and Ramp-Down times are defined as the time it takes for the PGA to sweep across 90% of its gain range.

All hold, ramp-up and ramp-down times scale proportionally with MCLK

Signal-to-noise ratio (dB) – SNR is a measure of the difference in level between the full scale output and the output

with no signal applied. (No Auto-zero or Automute function is employed in achieving these results).

THD+N (dB) – THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.

Channel Separation (dB) – Also known as Cross-Talk. This is a measure of the amount one channel is isolated from

the other. Measured by applying a full scale signal to one channel input and measuring the level of signal apparent at

the other channel output.

The maximum output voltage can be limited by the speaker power supply.

If OUT3BOOST, OUT4BOOST or

SPKBOOST is set then SPKVDD should be 1.5xAVDD to prevent clipping taking place in the output stage (when

PGA gains are set to 0dB).

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