WM8746

Production Data

w

March 2006, PD Rev 4.0

7

Test Conditions

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Analogue Output Levels

Load = 10kΩ,

0 dBFS,

(AVDD=5.0V)

1.1

Output level

Load = 10kΩ,

0 dBFS,

(AVDD=3.3V)

0.73

Gain mismatch

channel-to-channel

±1

%FSR

To midrail or a.c.

coupled

1

kΩ

Minimum resistance load

To midrail or a.c.

coupled

(AVDD = 3.3V)

1

kΩ

Maximum capacitance load

5V or 3.3V

100

pF

Output d.c. level

(AVDD1-

AGND)/2

V

Power On Reset (POR)

POR threshold

2.0

V

Notes:

1.

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.

2.

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.

3.

CAP 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 attenuation (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.