Production Data

WM8721 / WM8721L

w

PD Rev 4.0 November 2004

7

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.

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) - 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.

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.

POWER CONSUMPTION

CURRENT CONSUMPTION

MODE DESCRIPTION

AVDD

(3.3V)

HPVDD

(3.3V)

DCVDD

(1.5V)

DBVDD

(3.3V)

UNITS

DAC Playback

0

0

0

3.5

1.7

1.3

0.1

mA

Standby

0

1

1

17

0.4

0.7

0.2

µA

Power Down

1

1

1

0.4

0.3

0.7

0.1

µA

Table 1 Powerdown Mode Current Consumption Examples

Notes:

1.

2.

All figures are quiescent, with no signal.

3.

The power dissipation in the headphone itself not included in the above table.