Pre-Production
WM8940
Digital to Analogue Converter (DAC) to MONO Output with 10kΩ / 50pF load and DACVOL 0dB
Full-scale output 1
DACVOL = 0dB
A-weighted
AVDD1/3.3
98
Vrms
dB
3
Signal to Noise Ratio
SNR
THD
AVDD1=AVDD2=3.3V
0dBFS input
Total Harmonic Distortion 4
Total Harmonic Distortion + Noise 5
Channel Separation 6
-80
-78
100
dBFS
dBFS
dB
AVDD1=AVDD2=3.3V
THD+N
0dBFS input
AVDD1=AVDD2=3.3V
1kHz signal
MICP and MICN input PGA to input boost stage into 10kΩ / 50pF load on SPKOUTP and SPKOUTP
INPPGAVOL, PGABOOST = 0dB
Full-scale output voltage, 0dB gain
AVDD2/3.3
98
Vrms
dB
3
Signal to Noise Ratio
SNR
THD
A-weighted
AVDD1=AVDD2=3.3V
full-scale signal
Total Harmonic Distortion 4
Total Harmonic Distortion + Noise 5
Channel Separation 6
dBFS
dBFS
dB
-80
-78
AVDD1=AVDD2=3.3V
full-scale signal
THD+N
AVDD1=AVDD2=3.3V
100
Speaker Output (SPKOUTP, SPKOUTN with 8Ω bridge tied load)
Output Power
Total Harmonic Distortion 4
Po
Output power is closely correlated with THD see below
THD
Po=150mW, RL = 8Ω
0.03
%
dB
%
SPKVDD=3.3V
Po=350mW, RL = 8Ω
SPKVDD=3.3V
A-weighted
-68
2.944
-30.6
dB
Signal to Noise Ratio 3
SNR
dB
98
SPKVDD=3.3V
RL = 8Ω BTL
Power Supply Rejection Ratio
(50Hz-22kHz)
PSRR
50
dB
dB
Headphone Output (SPKOUTP, SPKOUTN with resistive load to GND)
Signal to Noise Ratio 3
SNR
A-weighted
SPKVDD=3.3V
98
Total Harmonic Distortion 4
THD
Po=20mW, RL = 16Ω
SPKVDD=3.3V
0.02
-72
%
dB
Microphone Bias
Bias Voltage
MBVSEL=0
MBVSEL=1
0.9*AVDD1
V
V
0.65*AVDD1
Bias Current Source
Output Noise Voltage
Digital Input / Output
Input HIGH Level
for VMICBIAS within +/-3%
1kHz to 20kHz
3
Ma
15
nV/√Hz
VIH
0.7×
V
DBVDD
Input LOW Level
VIL
0.3×DBVDD
V
V
Output HIGH Level
VOH
IOL=1mA
0.9×
DBVDD
Output LOW Level
Input Capacitance
VOL
IOH-1mA
0.1xDBVDD
V
All digital pins
10
pF
Pre-Production, Rev 3.0, February 2007
9
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
