WM8761 Production Data
w
PD, Rev 4.6, October 2011
7
Test Conditions
VDD = 5V, GND = 0V, T
A
= +25
o
C, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Analogue Output Levels
Output level
Load = 10k, 0dBFS 1.1 V
RMS
Load = 10k, 0dBFS,
(VDD = 3.3V)
0.72 V
RMS
Gain mismatch
channel-to-channel
±1 %FSR
Minimum resistance load
To midrail or a.c.
coupled
1 k
To midrail or a.c.
coupled
(VDD = 3.3V)
1 k
Maximum capacitance load
5V or 3.3V 100 pF
Output d.c. level
VDD/2 V
Power On Reset (POR)
POR threshold
2.4 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. CAP pin decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
4. Power down occurs 1.5s after MCLK is stopped.
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.
