wm8940gefl-v Wolfson Microelectronics plc, wm8940gefl-v Datasheet - Page 10

• Manufacturer Part Number: wm8940gefl-v
• Description: Mono Codec With Speaker Driver
• Manufacturer: Wolfson Microelectronics plc

WM8940
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TERMINOLOGY
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example, when AVDD = 3.3V, 0dBFS = 1V
with a linear relationship to AVDD.
reduced.
output with no signal applied. This ratio is also called idle channel noise. (No Auto-zero or Automute function is
employed in achieving these results).
harmonics of that signal. The reference output signal need not be at full scale amplitude; THD is typically measured
using an output power of 20mW into a 16ohm load, corresponding to a reference signal level of -5dB. However the
stated test conditions include input signal level, signal gain settings, output load characteristics and power supply
voltages To calculate the ratio, the fundamental frequency of the output signal is notched out and an RMS value of
the next seven harmonics is calculated.
the sum of the harmonics, wide-band noise and interference on the output signal. To calculate the ratio, the
fundamental frequency of the output signal is notched out and an RMS value of the total harmonics, wide-band noise
and interference is calculated.
the other. Normally measured by sending a full scale signal down
Full-scale input and output levels scale in relation to AVDD or SPKVDD depending upon the input or output used. For
Input level to RIP and LIP in differential configurations is limited to a maximum of -3dB or performance will be
Signal-to-noise ratio (dB) – SNR is the difference in level between a reference full scale output signal and the device
Total Harmonic Distortion (dB) – THD is the difference in level between a reference output signal and the first seven
Total Harmonic Distortion plus Noise (dB) – THD+N is the difference in level between a reference output signal and
Channel Separation (dB) – Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
rms
(0dBV). When AVDD < 3.3V the absolute level of 0dBFS will decrease
PD, Rev 4.2, April 2008
Production Data
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