WM8955 Ver la hoja de datos (PDF) - Wolfson Microelectronics plc

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Fabricante

WM8955

STEREO DAC FOR PORTABLE AUDIO APPLICATIONS

Wolfson Microelectronics plc 

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

PO

Output power is very closely correlated with THD; see below.

Total Harmonic Distortion

THD

Po=180mW, RL=8Ω,

-50

dB

HPVDD=3.3V

0.3

%

Po=400mW, RL=8Ω

-40

HPVDD=3.3V

1

Signal to Noise Ratio

SNR

HPVDD=3.3V, RL=8Ω

90

dB

(A-weighted)

HPVDD=2.5V, RL=8Ω

90

Analogue Reference Levels

Midrail Reference Voltage

VMID

–3%

AVDD/2

+3%

V

Buffered Reference Voltage

VREF

–3%

AVDD/2

+3%

V

VREF source current

IVREF

5

mA

VREF sink current

IVREF

5

mA

Digital Input / Output

Input HIGH Level

VIH

Input LOW Level

VIL

0.7×DBVDD

V

0.3×DBVDD

V

Output HIGH Level

VOH

0.9×DBVDD

V

Output LOW Level

VOL

0.1×DBVDD

V

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.

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).

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. Normally measured by sending a full scale signal down one channel and measuring the other.

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Product Preview Rev 0.4 May 2003

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