wm9708 Wolfson Microelectronics plc, wm9708 Datasheet - Page 30

• Manufacturer Part Number: wm9708
• Description: Ac?97 Revision 2.1 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9708
RECOMMENDED EXTERNAL COMPONENTS VALUES
Table 16 External Component Values
RECOMMENDATIONS FOR 3.3V OPERATION
w
C1
C2
C3
C4
C5 to C11
C12
C13
C14
C15
C16
C17 to C19
C20 and C21
XT
COMPONENT
REFERENCE
470nF
22pF
10μF
0.1μF
0.1μF
10μF
0.1μF
0.1μF
10μF
0.1μF
10μF
10μF
24.576 MHz
SUGGESTED
VALUE
The device’s performance with AVDD = 3.3V is shown in Electrical Characteristics.
In 3.3V analogue operation, mid-rail reference scales to 1.5V. All ADC and DAC references are 3/5
of their nominal 5V value. Input and output signals that are 1Vrms in 5V applications, scale to
660mVrms in 3.3V applications. If 1Vrms output is required, the mixer gain adjust PGAs need to be
increased by 3 times 1.5dB steps.
De-coupling for DVDD
De-coupling for AVDD
AC coupling capacitors for setting DC level of analogue inputs to VCAP.
Reference de-coupling capacitors for ADC, DAC and Mixer references.
Capacitors for crystal frequency stability.
AC’97 master clock frequency. A bias resistor is not required, but if connected will not
affect operation if value is large (above 1MΩ).
De-coupling for DVDD
De-coupling for AVDD
Value chosen to give corner frequency below 20Hz for min 10K input impedance.
Output AC coupling caps to remove VREF DC level from outputs.
DESCRIPTION
PD, Rev 4.2, August 2009
Production Data
30
ths