WM8985
Pre-Production
Test Conditions
DCVDD=1.8V, AVDD1=AVDD2=DBVDD=3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital Input / Output
Input HIGH Level
VIH
0.7×DBV
V
DD
Input LOW Level
VIL
0.3×DBVDD
V
V
Output HIGH Level
VOH
IOL=1mA
0.9×DBV
DD
Output LOW Level
Input Capacitance
Input leakage
VOL
IOH-1mA
0.1xDBVDD
V
All digital pins
10
pF
pA
TBD
TERMINOLOGY
1. Full-scale input and output levels scale in relation to AVDD or AVDD2 depending upon the input or output used. For
example, when AVDD = 3.3V, 0dBFS = 1Vrms (0dBV). When AVDD < 3.3V the absolute level of 0dBFS will decrease
with a linear relationship to AVDD.
2. Input level to RIP and LIP in differential configurations is limited to a maximum of -3dB or performance will be
reduced.
3. Signal-to-noise ratio (dBFS) – SNR is the difference in level between a reference full scale output signal and the
device output with no signal applied. This ratio is also called idle channel noise. (No Auto-zero or Automute function is
employed in achieving these results).
4. Total Harmonic Distortion (dBFS) – THD is the difference in level between a reference full scale output signal and the
first seven odd harmonics of the output signal. To calculate the ratio, the fundamental frequency of the output signal
is notched out and an RMS value of the next seven harmonics is calculated.
5. Total Harmonic Distortion plus Noise (dBFS) – THD+N is the difference in level between a reference full scale output
signal and the sum of the harmonics, wide-band noise and interference on the output signal. To calculate the ratio,
the fundamental frequency of the output signal is notched out and an RMS value of the total harmonics, wide-band
noise and interference is calculated.
6. 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.
PP, Rev 3.4, October 2006
14
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
