Advanced Information

WM8722

WOLFSON MICROELECTRONICS LTD

AI Rev 1.5 May 2000

5

Test Conditions

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Gain mismatch

Channel to channel

+/-1%

+/-5%

% of FSR

Frequency Bandwidth

0dB gain

100

kHz

Master volume max gain

567

dB

Master volume min gain

-70

-73

-76

dB

Master volume step size,

codes 0 - 47

0.7

1

1.3

dB

Master volume step size,

codes 48 – 79

0.5

1

1.5

dB

Master volume gain code

80 – 127 (mute)

-90

-100

dB

Mixer trim max gain

11

12

13

dB

Mixer trim min gain

-32.5

-34.5

-36.5

dB

Mixer trim step size

1.3

1.5

1.7

dB

Tone Generator

SINAD (Note 3)

1Hz to 1kHz tones

65

75

dB

SINAD

1kHz to 2kHz tones

60

70

dB

SINAD

2kHz to 4kHz tones

55

65

dB

SINAD

4kHz to 32kHz tones

50

60

dB

Full scale output voltage;

trims at

0dB

2.5

V pk-pk

Tone Frequency

TCLK frequency = 27MHz

1

32767

Hz

Tone Duration

TCLK frequency = 27MHz

0.1

25.5

secs

Gain adjust range

-46.5

0

dB

Gain adjust step size (4

bit trim)

1.25

1.5

1.75

dB

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. 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.

SINAD is ratio of signal to sum of noise, harmonics and spurii, over a bandwidth from 1Hz up to either 127x the

tone frequency, or 20kHz, whichever is the lower. (This is to allow for the lower frequency tones having images

at 127x and 129x the tone frequency which will fall in the audio band for tones of frequency less than about

20kHz/128).