WM8731_09 Datasheet, PDF (13/64 Pages) Wolfson Microelectronics plc – Portable Internet Audio CODEC with Headphone Driver and Programmable Sample Rates

WM8731 / WM8731L
Production Data
Test Conditions
AVDD, HPVDD, DBVDD = 1.8V, AGND = 0V, DCVDD = 1.5V, DGND = 0V, TA = +25^oC, Slave Mode, fs = 48kHz, XTI/MCLK =
256fs unless otherwise stated.
Stereo Headphone Output
0dB Full scale output voltage
1.0 x
Vrms
AVDD/3.3
Max Output Power
PO
RL = 32 Ω
9
mW
RL = 16 Ω
18
Signal to Noise Ratio
SNR
A-weighted
86
95
dB
(Note 1,3)
Total Harmonic Distortion
THD
1kHz, -5dB FS signal
0.08
0.1
%
RL = 32Ω
-62
-60
dB
1kHz, -2dB FS signal
1
RL = 32Ω
-40
Power Supply Rejection Ratio
PSRR
1kHz 100mVpp
50
dB
20Hz - 20kHz, 100mVpp
45
Programmable Gain
1kHz
-73
0
6
dB
Programmable Gain Step Size
1kHz
1
dB
Mute attenuation
1kHz, 0dB
80
dB
Microphone Input to Headphone Output Side Tone Mode
0dB Full scale output voltage
1.0 x
Vrms
AVDD/3.3
Signal to Noise Ratio
SNR
85
90
dB
(Note 1,3)
Power Supply Rejection Ratio
PSRR
1kHz 100mVpp
50
dB
20Hz to 20kHz
45
100mVpp
Programmable Attenuation
1kHz
6
15
dB
Programmable Attenuation Step
Size
1kHz
3
dB
Mute attenuation
1kHz, 0dB
80
dB
Notes:
1. Ratio of output level with 1kHz full scale input, to the output level with the input short circuited, measured ‘A’ weighted over a 20Hz
to 20kHz bandwidth using an Audio analyser.
2. Ratio of output level with 1kHz full scale input, to the output level with all zeros into the digital input, measured ‘A’ weighted over a
20Hz to 20kHz bandwidth.
3. All performance measurements done with 20kHz low pass filter, and where noted an A-weight filter. Failure to use such a filter will
result in higher THD+N and lower SNR and Dynamic Range readings than are found in the Electrical Characteristics. The low
pass filter removes out of band noise; although it is not audible it may affect dynamic specification values.
4. VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
TERMINOLOGY
1. 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).
2. Dynamic range (dB) - DR is a measure of the difference between the highest and lowest portions of a signal.
Normally a THD+N measurement at 60dB below full scale. The measured signal is then corrected by adding the 60dB
to it. (e.g. THD+N @ -60dB= -32dB, DR= 92dB).
3. THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.
4. Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
the other. Normally measured by sending a full scale signal down one channel and measuring the other.
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PD, Rev 4.8, April 2009
13