WM8985GEFL Wolfson Microelectronics, WM8985GEFL Datasheet - Page 69

• Manufacturer Part Number: WM8985GEFL
• Description: Audio CODECs Multimedia CODEC with Class D HP
• Manufacturer: Wolfson Microelectronics

Specifications of WM8985GEFL

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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CLASS D / CLASS AB HEADPHONE OUTPUTS (LOUT2 AND ROUT2)
Table 35 Class D Control Registers
Figure 27 LOUT2 and ROUT2 Class D Headphone Configuration
The outputs LOUT2 and ROUT2 are designed to drive two headphone loads of 16Ω or 32Ω or line
outputs (See Headphone Output and Line Output sections, respectively). Each output has an
individual volume control PGA, a mute and an enable control bit as shown in Figure 27. LOUT2 and
ROUT2 output the left and right channel mixer outputs respectively.
When driving headphones using class D outputs it is necessary to use appropriate filtering, placed
close to the device, to minimise EMI emissions from the headphone cable (Refer to "Applications
Information" for more information). This filtering does not prevent class AB mode operation.
R7 (07h)
R23 (17h)
REGISTER
ADDRESS
7:4
8
BIT
DCLKDIV
CLASSDEN
LABEL
DEFAULT
1000
0
Controls clock division from
SYSCLK to generate suitable class
D clock.
Recommended class D clock
frequency = 1.4MHz.
0000 = divide by 1
0010 = divide by 2
0011 = divide by 3
0100 = divide by 4
0101 = divide by 5.5
0110 = divide by 6
1000 = divide by 8
1001 = divide by 12
1010 = divide by 16
Enable signal for class D mode on
LOUT2 and ROUT2
0 = Class AB mode
1 = Class D mode
DESCRIPTION
PD, Rev 4.6, July 2009
WM8985
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