WM8728
Test Conditions
AVDD, DVDD = 5V, AGND = 0V, DGND = 0V, T
A
= +25
o
C, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER
Analogue Output Levels
Output level
Load = 10kΩ, 0dBFS
Load = 10kΩ, 0dBFS,
(AVDD = 3.3V)
1.1
0.726
±1
To midrail or a.c.
coupled
To midrail or a.c.
coupled
(AVDD = 3.3V)
5V or 3.3V
1
600
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
Production Data
UNIT
V
RMS
V
RMS
%FSR
kΩ
ohms
Gain mismatch
channel-to-channel
Minimum resistance load
Maximum capacitance load
Output d.c. level
Power On Reset (POR)
POR threshold
100
(VREFP -
VREFN)/2
2.4
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, 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.
2.
Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full-scale output and the output with a
ZERO signal applied. (No Auto-ZERO or Automute function is employed in achieving these results).
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).
THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.
Stop band attenuation (dB) - Is the degree to which the frequency spectrum is attenuated (outside audio band).
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.
3.
4.
5.
w
PD, Rev 4.6 August 2008
7
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
