WM8734
Production Data
Test Conditions
AVDD, DBVDD = 3.3V, AGND = 0V, DCVDD = 3.3V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK = 256fs unless
otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Vrms
dB
Line Output for DAC Playback Only (Load = 47kΩ. 50pF)
0dBfs Full scale output voltage
At LINE outputs
1.0 x
AVDD/3.3
100
Signal to Noise Ratio
(Note 1,2,3)
SNR
A-weighted,
@ fs = 48kHz
A-weighted
95
98
98
@ fs = 96kHz
A-weighted,
@ fs = 48kHz,
AVDD = 2.7V
Dynamic Range (Note 3)
Total Harmonic Distortion
DNR
THD
A-weighted, -60dB full
scale input
85
95
dB
dB
1kHz, 0dBfs
1kHz, -3dBfs
1kHz 100mVpp
-88
-92
50
-80
Power Supply Rejection Ratio
PSSR
dB
dB
20Hz to 20kHz
100mVpp
45
DAC channel separation
1kHz, 0dB
100
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) - DNR 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. Stop band attentuation (dB) – Is the degree to which the frequency spectrum is attenuated (outside audio band).
5. 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.
6. Pass-Band Ripple – Any variation of the frequency response in the pass-band region.
PD Rev 4.1 November 2006
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
