WM8731 Wolfson Microelectronics Ltd., WM8731 Datasheet - Page 29

• Manufacturer Part Number: WM8731
• Description: WM8731 : Low Power Audio Codec With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8731
Figure 22 Signal Routing in Bypass Mode
LINEIN
12.5K
VMID
The recommended external components required to complete the application are shown in Figure 21.
Figure 21 Headphone Output Application Drawing
Recommended values are C1 = 220uF (10V electrolytic), R1 = 47k
C1 forms a DC blocking capacitor to isolate the dc of the HPOUT from the headphones. R1 form a
pull down resistor to discharge C1 to prevent the voltage at the connection to the headphones from
rising to a level that may damage the headphones.
BYPASS MODE
The WM8731 includes a bypass mode whereby analogue line inputs are routed directly to the
analogue line outputs and headphone outputs. The scheme for this is in Figure 22.
HPOUT
INPUTS
FROM
FROM
LINE
DAC
SIDETONE (OFF)
DACSEL (OFF)
BYPASS (ON)
VMID
C1
AGND
R1
LINEOUT
VMID
AI Rev 2.3 August 2001
Advanced Information
AGND
HPOUT
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