WM8738

Production Data

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PD Rev 4.4 August 2006

6

ELECTRICAL CHARACTERISTICS

Test Conditions

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Digital Logic Levels (TTL Levels)

Input LOW level

0.8

V

Input HIGH level

2.0

V

Output LOW

0.1 x DVDD

V

Output HIGH

0.9 x DVDD

V

Pull down resistance (FMT,

NOHP)

100

k

Ω

Analogue Reference Levels

Reference voltage

AVDD/2 –

50mV

AVDD/2

AVDD/2 +

50mV

V

Buffered reference voltage

V

Potential divider output

impedance

40

50

60

k

Ω

Input to ADC

Input Signal Level (0dB)

1.0

Vrms

SNR (Note 1)

A-weighted, 0dB gain

@ fs = 48KHz

90

dB

SNR (Note 1)

A-weighted, 0dB gain

@ fs = 96KHz

90

dB

SNR (Note 1)

A-weighted, 0dB gain

@ fs = 48KHz, AVDD =

3.3V

90

dB

Dynamic Range (Note 2)

DNR

A-weighted, -60dB full

scale input

90

97

dB

Total Harmonic Distortion (THD)

(Note 3)

-1dB input, 0dB gain

-87

dB

ADC channel separation (Note

5)

1KHz input

95

dB

50

dB

Power Supply Rejection Ratio

PSRR

20Hz to 20kHz

45

dB

Input Resistance

20

k

Ω

Input Capacitance

10

pF

Notes

1.

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

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.

VREF and CAP de-coupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).

4.

This data is measured, using an active filter on the device inputs.