WM8738
ELECTRICAL CHARACTERISTICS
Production Data
Test Conditions
AVDD = 5.0V, AGND = 0V, DVDD = 3.3V, DGND = 0V, T
A
= +25
o
C, fs = 48kHz, MCLK = 256fs unless otherwise stated.
PARAMETER
Digital Logic Levels (TTL Levels)
Input LOW level
Input HIGH level
Output LOW
Output HIGH
Pull down resistance (FMT,
NOHP)
Analogue Reference Levels
Reference voltage
Buffered reference voltage
Potential divider output
impedance
Input to ADC
Input Signal Level (0dB)
SNR (Note 1,2)
SNR (Note 1,2)
SNR (Note 1,2)
V
RIN
/ V
LIN
A-weighted, 0dB gain
@ fs = 48KHz
A-weighted, 0dB gain
@ fs = 96KHz
A-weighted, 0dB gain
@ fs = 48KHz, AVDD =
3.3V
DNR
A-weighted, -60dB full
scale input
-1dB input, 0dB gain
1KHz input
PSRR
1kHz 100mV
p-p
20Hz to 20kHz
100mV
p-p
Input Resistance
Input Capacitance
Notes
1.
2.
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.
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.
VREF and CAP de-coupled with 10uF and 0.1uF capacitors (smaller values may result in reduced performance).
This data is measured, using an active filter on the device inputs.
90
1.0
90
90
90
Vrms
dB
dB
dB
V
CAP
V
REF
R
CAP
40
AVDD/2 –
50mV
AVDD/2
V
CAP
50
60
AVDD/2 +
50mV
V
V
kΩ
V
IL
V
IH
V
OL
V
OH
R
PD
I
OL
= 1mA
I
OH
= 1mA
0.9 x DVDD
100
2.0
0.1 x DVDD
0.8
V
V
V
V
kΩ
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Dynamic Range (Note 2)
Total Harmonic Distortion (THD)
(Note 4)
ADC channel separation
Power Supply Rejection Ratio
97
-87
95
50
45
20
10
dB
dB
dB
dB
dB
kΩ
pF
3.
4.
w
PD Rev 4.3 November 2004
6
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
