WM8738
Production Data
ELECTRICAL CHARACTERISTICS
Test Conditions
AVDD = 5.0V, AGND = 0V, DVDD = 3.3V, DGND = 0V, TA = +25oC, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Digital Logic Levels (TTL Levels)
Input LOW level
VIL
VIH
0.8
V
V
Input HIGH level
Output LOW
2.0
VOL
VOH
RPD
I
OL = 1mA
0.1 x DVDD
V
Output HIGH
I
OH = 1mA
0.9 x DVDD
V
Pull down resistance (FMT,
NOHP)
100
kΩ
Analogue Reference Levels
Reference voltage
VCAP
AVDD/2 –
50mV
AVDD/2
AVDD/2 +
50mV
V
Buffered reference voltage
VREF
RCAP
VCAP
50
V
Potential divider output
impedance
40
60
kΩ
Input to ADC
Input Signal Level (0dB)
SNR (Note 1,2)
VRIN / VLIN
1.0
90
Vrms
dB
A-weighted, 0dB gain
@ fs = 48KHz
SNR (Note 1,2)
SNR (Note 1,2)
A-weighted, 0dB gain
@ fs = 96KHz
90
90
dB
dB
A-weighted, 0dB gain
@ fs = 48KHz, AVDD =
3.3V
Dynamic Range (Note 2)
DNR
A-weighted, -60dB full
scale input
90
97
dB
dB
Total Harmonic Distortion (THD)
(Note 4)
-1dB input, 0dB gain
-87
ADC channel separation
Power Supply Rejection Ratio
1KHz input
1kHz 100mVp-p
20Hz to 20kHz
100mVp-p
95
50
45
dB
dB
dB
PSRR
Input Resistance
Input Capacitance
20
10
kΩ
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.
PD Rev 4.3 November 2004
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
