WM8951L_07 WOLFSON [Wolfson Microelectronics plc], WM8951L_07 Datasheet - Page 7

• Manufacturer Part Number: WM8951L_07
• Description: Stereo ADC with Microphone Input and Clock Generator
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
Notes:
1.
2.
3.
4.
TERMINOLOGY
1.
2.
3.
4.
w
Test Conditions
AVDD1, AVDD2, DBVDD = 3.3V, AGND1, AGND2 = 0V, DCVDD = 1.5V, DGND = 0V, T
XTI/MCLK = 256fs unless otherwise stated.
Microphone Input to ADC @ 0dB Gain, fs = 48kHz (40kΩ Source Impedance. See Figure 11)
Input Signal Level (0dB)
Signal to Noise Ratio
(Note 1,3)
Dynamic Range (Note 3)
Total Harmonic Distortion
Power Supply Rejection Ratio
Programmable Gain Boost
Mic Path gain (MICBOOST gain
is additional to this nominal
gain)
Mute attenuation
Input Resistance
Input Capacitance
Microphone Bias
Bias Voltage
Bias Current Source
Output Noise Voltage
to 20kHz bandwidth using an Audio analyser.
20Hz to 20kHz bandwidth.
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.
with no signal applied. (No Auto-zero or Automute function is employed in achieving these results).
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).
the other. Normally measured by sending a full scale signal down one channel and measuring the other.
Ratio of output level with 1kHz full scale input, to the output level with the input short circuited, measured ‘A’ weighted over a 20Hz
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
All performance measurements done with 20kHz low pass filter, and where noted an A-weight filter. Failure to use such a filter will
VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full scale output and the output
Dynamic range (dB) - DR is a measure of the difference between the highest and lowest portions of a signal.
THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.
Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
MICBOOST bit
V
I
PSRR
R
C
V
MICBIAS
SNR
MICBIAS
THD
DR
set
INMIC
INMIC
INMIC
Vn
AVDD1/2= DBVDD=1.8V
AVDD1/2= DBVDD=1.8V
AVDD1/2= DBVDD=1.8V
A-weighted, -60dB full
A-weighted, 0dB gain
Rsource < 50 Ohms
0dB input, 0dB gain
MICBOOST = 0
0dB, 1kHz input
1kHz 100mVpp
Rsource < 50Ω
20Hz to 20kHz
DCVDD=1.5V
DCVDD=1.5V
DCVDD=1.5V
1K to 20kHz
scale input
1kHz input
100mVpp
0.75*AVDD1
–100mV
0.75*AVDD1 0.75*AVDD1
A
AVDD/3.3
= +25
10k
1.0
-55
80
70
50
45
34
14
80
10
25
o
C, Slave Mode, fs = 48kHz,
PD Rev 4.1 December 2007
+ 100mV
3
WM8951
nV/√Hz
Vrms
mA
dB
dB
dB
dB
dB
dB
dB
dB
pF
Ω
V
7