wm8941 Wolfson Microelectronics plc, wm8941 Datasheet - Page 10

• Manufacturer Part Number: wm8941
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

WM8941
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TERMINOLOGY
1.
2.
3.
4.
5.
6.
Test Conditions
DCVDD=1.8V, DBVDD=3.3V, AVDD=3.3V, SPKVDD =3.3V, , VBVDD=3.3V, T
unless otherwise stated.
PARAMETER
Low pass filter order
Low Pass Filter Response (referenced to 100kHz)
Response at 2.4MHz
Response at 5.13MHz
Response at 9.04MHz
Response at 13.32MHz
Microphone Bias
Bias Voltage
Bias Current Source
Output Noise Voltage
Digital Input / Output
Input HIGH Level
Input LOW Level
Output HIGH Level
Output LOW Level
Input Capacitance
Input leakage
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 = 1V
with a linear relationship to AVDD.
Input level to RIP and LIP in differential configurations is limited to a maximum of -3dB or performance will be reduced.
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).
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.
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.
The Gain is dependant on the external resistor values of R
nominal values shown.
SYMBOL
V
V
V
V
OH
OL
IH
IL
rms
(0dBV). When AVDD < 3.3V the absolute level of 0dBFS will decrease
All digital pins except MODE
R
for V
VBREF
R
TEST CONDITIONS
LOAD
1kHz to 20kHz
MICBIAS
All digital pins
=187Ω, R
MBVSEL=0
MBVSEL=1
MODE pin
=75Ω, 0dB gain
I
VBREF
I
OL
OH
=1mA
-1mA
within +/-3%
, R
OUT
OUT
=75Ω,
, and R
A
= +25
LOAD.
GND-0.7
DBVDD
DBVDD
AVDD
0.85*
-11.0
GND
0.7×
0.9×
-900
-0.1
-0.5
-3.0
-90
o
MIN
The specified values are using the
C, 1kHz signal, fs = 48kHz, 24-bit audio data
0.65*AVDD
0.9*AVDD
3
-0.2
-1.6
-7.0
15
10
TYP
rd
0
order
PD, Rev 4.0, August 2008
DBVDD+0.7
0.3×DBVDD
0.1xDBVDD
DBVDD
AVDD
0.95*
+900
+90
MAX
-3.0
0.1
0.1
3
0
Production Data
nV/√Hz
mA
UNIT
μA
dB
dB
dB
dB
pF
nA
V
V
V
V
V
V
10