WM8729 Datasheet, PDF (5/15 Pages) Wolfson Microelectronics plc – 24-bit, 192kHz Stereo DAC

WM8729
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Test Conditions
AVDD, DVDD = 5V, AGND = 0V, DGND = 0V, TA = +25^oC, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER
SYMBOL TEST CONDITIONS
MIN
TYP
MAX
Minimum resistance load
To midrail or a.c.
1
coupled
To midrail or a.c.
600
coupled
(AVDD = 3.3V)
Maximum capacitance load
5V or 3.3V
100
Output d.c. level
(VREFP -
VREFN)/2
Power On Reset (POR)
POR threshold
2.4
UNIT
kohms
ohms
pF
V
V
Notes:
1. 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.
2. 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.
3. 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 attenuation (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.
WOLFSON MICROELECTRONICS LTD
PP Rev 1.2 April 2001
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