WM8734 Просмотр технического описания (PDF) - Wolfson Microelectronics plc

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производитель

WM8734

Stereo Audio CODEC

Wolfson Microelectronics plc 

WM8734

Production Data

Test Conditions

AVDD, DBVDD = 3.3V, AGND = 0V, DCVDD = 3.3V, DGND = 0V, TA = +25oC, Slave Mode, fs = 48kHz, MCLK = 256fs unless

otherwise stated.

PARAMETER

SYMBOL TEST CONDITIONS

MIN

TYP

MAX

UNIT

Line Output for DAC Playback Only (Load = 47kΩ. 50pF)

0dBfs Full scale output voltage

At LINE outputs

1.0 x

Vrms

AVDD/3.3

Signal to Noise Ratio

SNR

A-weighted,

95

100

dB

(Note 1,2,3)

@ fs = 48kHz

A-weighted

98

@ fs = 96kHz

A-weighted,

98

@ fs = 48kHz,

AVDD = 2.7V

Dynamic Range (Note 3)

DNR

A-weighted, -60dB full 85

95

dB

scale input

Total Harmonic Distortion

THD

1kHz, 0dBfs

-88

-80

dB

1kHz, -3dBfs

-92

Power Supply Rejection Ratio

PSSR

1kHz 100mVpp

50

dB

20Hz to 20kHz

45

100mVpp

DAC channel separation

1kHz, 0dB

100

dB

Notes:

1. Ratio of output level with 1kHz full scale input, to the output level with the input short circuited, measured ‘A’ weighted

over a 20Hz to 20kHz bandwidth using an Audio analyser.

2. 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 20Hz to 20kHz bandwidth.

3. All performance measurements done with 20kHz low pass filter, and where noted an A-weight filter. Failure to use

such a filter will 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.

4. VMID decoupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).

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) - DNR 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. Stop band attentuation (dB) – Is the degree to which the frequency spectrum is attenuated (outside audio band).

5. 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.

6. Pass-Band Ripple – Any variation of the frequency response in the pass-band region.

w

PD Rev 4.1 November 2006

9

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