WM8955L
Product Preview
Test Conditions
DCVDD = 1.5V, AVDD = HPVDD = 3.3V, TA = +25oC, 1kHz signal, fs = 48kHz, 24-bit audio data unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Speaker Output (LOUT2/ROUT2 with 8Ω bridge tied load, ROUT2INV=1)
Output Power per channel
Total Harmonic Distortion
PO
Output power is verycloselycorrelated with THD; see below.
THD
Po=180mW, RL=8Ω,
-50
0.3
-40
1
dB
%
HPVDD=3.3V
Po=400mW, RL=8Ω
HPVDD=3.3V
Signal to Noise Ratio
(A-weighted)
SNR
HPVDD=3.3V, RL=8Ω
HPVDD=2.5V, RL=8Ω
90
90
dB
Analogue Reference Levels
Midrail Reference Voltage
Buffered Reference Voltage
VREF source current
VREF sink current
VMID
VREF
IVREF
–3%
–3%
AVDD/2
AVDD/2
+3%
+3%
5
V
V
mA
mA
IVREF
5
Digital Input / Output
Input HIGH Level
VIH
VIL
0.7×DBVDD
0.9×DBVDD
V
V
V
V
Input LOW Level
0.3×DBVDD
0.1×DBVDD
Output HIGH Level
VOH
VOL
Output LOW Level
TERMINOLOGY
1. 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).
2. Dynamic range (dB) - DR is a measure of the difference between the highest and lowest portions of a signal.
Normallya THD+N measurement at 60dB below full scale. The measured signal is then corrected byadding the 60dB
to it. (e.g. THD+N @ -60dB= -32dB, DR= 92dB).
3. THD+N (dB) - THD+N is a ratio, of the rms values, of (Noise + Distortion)/Signal.
4. Channel Separation (dB) - Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
the other. Normallymeasured bysending a full scale signal down one channel and measuring the other.
Product Preview Rev 0.4 May2003
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
