WM8955L
Product Preview
Test Conditions
DCVDD = 1.5V, AVDD = HPVDD = 3.3V, T
A
= +25
o
C, 1kHz signal, fs = 48kHz, 24-bit audio data unless otherwise stated.
PARAMETER
Output Power per channel
Total Harmonic Distortion
SYMBOL
P
O
THD
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Speaker Output (LOUT2/ROUT2 with 8Ω bridge tied load, ROUT2INV=1)
Ω
Output power is very closely correlated with THD; see below.
Po=180mW, R
L
=8Ω,
HPVDD=3.3V
Po=400mW, R
L
=8Ω
HPVDD=3.3V
Signal to Noise Ratio
(A-weighted)
Analogue Reference Levels
Midrail Reference Voltage
Buffered Reference Voltage
VREF source current
VREF sink current
Digital Input / Output
Input HIGH Level
Input LOW Level
Output HIGH Level
Output LOW Level
V
IH
V
IL
V
OH
V
OL
0.9×DBVDD
0.1×DBVDD
0.7×DBVDD
0.3×DBVDD
V
V
V
V
VMID
VREF
I
VREF
I
VREF
–3%
–3%
AVDD/2
AVDD/2
+3%
+3%
5
5
V
V
mA
mA
SNR
HPVDD=3.3V, R
L
=8Ω
HPVDD=2.5V, R
L
=8Ω
-50
0.3
-40
1
90
90
dB
dB
%
TERMINOLOGY
1.
2.
Signal-to-noise ratio (dB) - SNR is a measure of the difference in level between the full scale output and the output
with no signal applied. (No Auto-zero or Automute function is employed in achieving these results).
Dynamic range (dB) - DR is a measure of the difference between the highest and lowest portions of a signal.
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).
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
the other. Normally measured by sending a full scale signal down one channel and measuring the other.
3.
4.
w
Product Preview Rev 0.4 May 2003
6
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
