WM8941
Pre Production
Test Conditions
DCVDD=1.8V, DBVDD=3.3V, AVDD=3.3V, SPKVDD =3.3V, , VBVDD=3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data
unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
3rd order
MAX
UNIT
Low pass filter order
Low Pass Filter Response (referenced to 100kHz)
Response at 2.4MHz
R
VBREF=187Ω, ROUT=75Ω,
-0.1
-0.5
0
0.1
0.1
0
dB
dB
dB
dB
RLOAD=75Ω, 0dB gain
Response at 5.13MHz
-0.2
-1.6
-7.0
Response at 9.04MHz
-3.0
Response at 13.32MHz
-11.0
-3.0
Microphone Bias
Bias Voltage
MBVSEL=0
MBVSEL=1
0.85*
AVDD
0.9*AVDD
0.95*
AVDD
V
0.65*AVDD
V
Bias Current Source
Output Noise Voltage
Digital Input / Output
for VMICBIAS within +/-3%
1kHz to 20kHz
3
mA
15
nV/√Hz
Input HIGH Level
VIH
0.7×
DBVDD
DBVDD+0.7
V
Input LOW Level
VIL
GND-0.7
0.3×DBVDD
DBVDD
V
V
Output HIGH Level
VOH
IOL=1mA
0.9×
DBVDD
Output LOW Level
Input Capacitance
Input leakage
VOL
IOH-1mA
GND
0.1xDBVDD
V
All digital pins
10
pF
nA
µA
All digital pins except MODE -900
MODE pin -90
+900
+90
TERMINOLOGY
1. Full-scale input and output levels scale in relation to AVDD or SPKVDD 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 (dB) – 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 (dB) – THD is the difference in level between a reference output signal and the first seven
harmonics of that signal. The reference output signal need not be at full scale amplitude; THD is typically measured
using an output power of 20mW into a 16ohm load, corresponding to a reference signal level of -5dB. However the
stated test conditions include input signal level, signal gain settings, output load characteristics and power supply
voltages 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. THD is the difference in level between a reference output signal and the first seven 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.
6. Total Harmonic Distortion plus Noise (dB) – THD+N is the difference in level between a reference 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.
PP, Rev 3.3, December 2007
10
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
