WM8739 / WM8739L

Advanced Information

AI Rev 2.2 September 2001

5

ELECTRICAL CHARACTERISTICS

Test Conditions

unless otherwise stated.

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Digital Logic Levels (CMOS Levels)

Input LOW level

0.3 x VDD

V

Input HIGH level

0.7 x VDD

V

Output LOW

0.1 x VDD

V

Output HIGH

0.9 x VDD

V

Analogue Reference Levels

Reference voltage

AVDD/2

V

Potential divider resistance

50K

Ohms

Input to ADC

AVDD = 3.3V

1.0

0

Vrms

dB

Input Signal Level (0dB)

AVDD = 1.8V

(WM8739 only)

0.316

-10

0.545

-5.27

Vrms

dBV

A-weighted, 0dB gain

85

90

dB

A-weighted, 0dB gain

@ fs = 96kHz

90

dB

A-weighted, 0dB gain,

AVDD = 2.7V

88

dB

Signal to Noise Ratio (Note 1,2)

SNR

A-weighted, 0dB gain,

AVDD = 1.8V

(WM8739L only)

76

dB

Dynamic Range (Note 2)

DNR

A-weighted, -60dBV

85

90

dB

-1dBV input, 0dB gain

-84

0.006

-74

0.02

dB

%

Total Harmonic Distortion

THD

-10dBV, 0dB gain

-74

0.02

dB

%

ADC channel separation

1kHz input

90

dB

Programmable Gain

1kHz input

Rsource < 50 Ohms

-34.5

0

+12

dB

Programmable Gain Step Size

1.5

dB

Mute attenuation

0dB, 1kHz input

80

dB

0dB gain

20k

30k

Ohms

Input Resistance

12dB gain

10k

15k

Ohms

Input Capacitance

10

pF

Notes

1.

Ratio of output level with 1kHz full scale input, to the output level with all zero’s into the digital input over a 20Hz to

20kHz bandwidth using an Audio analyser.

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).