WM8731_09 Datasheet, PDF (21/64 Pages) Wolfson Microelectronics plc – Portable Internet Audio CODEC with Headphone Driver and Programmable Sample Rates

WM8731 / WM8731L
Production Data
AVDD
VMID
AGND
MICBIAS
RLINEIN
MICIN
LLINEIN
VOL
+12 to -34.5dB, 1.5dB Steps,
Reg 02h
RLINEIN Mute
Reg 02h
INSEL, Reg 08h
MUTE
MUTE
MUX
ADC
0dB/
20dB
MIC BOOST Reg 08h
VOL
+12 to -34.5dB, 1.5dB Steps,
Reg 00h
MUTE
MUTE
MUX
ADC
LLINEIN Mute INSEL, Reg 08h
Reg 00h
OSCPD
Reg 0Ch
OSC
CLKIN
DIVIDER
(Div x1, x2)
CLKODIV2, Reg 10h
CLKOUT
DIVIDER
(Div x1, x2)
CLKIDIV2, Reg 10h
CLKOUTPD, Reg 0Ch
CONTROL INTERFACE
WM8731
DIGITAL
FILTERS
Bypass, Reg 08h
MUTE
ATTEN/
MUTE
SIDEATT,
Reg 08h
DAC
MUTE
DACMUTE
Reg 0Ah
+6 to -73dB
1 dB Steps, Reg 06h
VOL/
MUTE
H/P
DRIVER
Σ
SIDETONE
Reg 08h
DAC
DACMUTE
Reg 0Ah
MUTE
SIDETONE
Reg 08h
Σ
SIDEATT,
Reg 08h
ATTEN/
MUTE
MUTE
VOL/
MUTE
H/P
DRIVER
+6 to -73dB
1 dB Steps, Reg 04h
DIGTAL AUDIO INTERFACE
Bypass, Reg 08h
HPVDD
HPGND
RHPOUT
ROUT
LOUT
LHPOUT
Figure 9 Functional Block Diagram
AUDIO SIGNAL PATH
LINE INPUTS
The WM8731/L provides Left and Right channel line inputs (RLINEIN and LLINEIN). The inputs are
high impedance and low capacitance, thus ideally suited to receiving line level signals from external
hi-fi or audio equipment.
Both line inputs include independent programmable volume level adjustments and ADC input mute.
The scheme is illustrated in Figure 10. Passive RF and active Anti-Alias filters are also incorporated
within the line inputs. These prevent high frequencies aliasing into the audio band or otherwise
degrading performance.
LINEIN
12.5k
VMID
To
ADC
Figure 10 Line Input Schematic
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PD, Rev 4.8, April 2009
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