WM8738 Datasheet, PDF (6/15 Pages) Wolfson Microelectronics plc – 24 BIT STEREO ADC

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