WM8900LGEFK/RV Wolfson Microelectronics, WM8900LGEFK/RV Datasheet - Page 52

• Manufacturer Part Number: WM8900LGEFK/RV
• Description: Audio CODECs Ultra Low Power Hi-Fi CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8900LGEFK/RV

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8900
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LINE OUTPUT ENABLE
Each analogue output driver can be independently enabled via the Power Management register
bits, as described in Table 37. Muting and volume control of the outputs is only possible when the
correct power management register bits are enabled. When the correct power management bit for
an output is not set, some signal leakage to the output pin may occur.
Table 37 Line Output Enable
LINEOUT_1L AND LINEOUT_1R OUTPUTS
The outputs LINEOUT_1L and LINEOUT_1R are capable of driving a 16Ω headphone load and
are independently controlled by the register bits described in Table 38.
The outputs can be independently muted and the volumes controlled in the range -57dB to +6dB.
To allow simultaneous volume updates of left and right channels, output gains are not altered until
a 1 is written to the OUT1_VU bit.
To prevent "zipper noise", a zero-cross function is provided, so that when enabled, volume updates
will not take place until a zero-crossing is detected. In the event of a long period without zero-
crossings, a timeout function is available. When this function is enabled (using the TOCLK_ENA
register bit), the volume will update after the timeout period if no earlier zero-cross has occurred.
The timeout period is set by TOCLK_RATE. Note that this timer is the same timer as applied to the
Input PGA zero-cross function.
LCOM FUNCTION
Common ground noise on LINEOUT1L and LINEOUT1R outputs can be eliminated by enabling the
OUT1_FB_ENA bit. This allows the connection of the AUX/LCOM pin to the shared LINEOUT
ground via a 4.7µF capacitor. Note that the AUX/LCOM pin cannot be used as an auxiliary input
when used as a common ground connection. It is recommended that the AUX input is not
connected to the output mixers (see register R48; IN4_TO_MIXOUTL and IN4_TO_MIXOUTR bits)
and that the AUX boost stages are muted (R27; IN4L_BOOST and IN4R_BOOST) when using this
configuration. This configuration can be seen below.
R2 (02h)
Power
Management
2
R3 (03h)
Power
Management
3
REGISTER
ADDRESS
8
7
6
5
BIT
OUT1L_ENA
OUT1R_ENA
OUT2L_ENA
OUT2R_ENA
LABEL
0
0
0
0
DEFAULT
Left channel LINEOUT1 enable
0 = LINEOUT_1L disabled
1 = LINEOUT_1L enabled
Right channel LINEOUT1 enable
0 = LINEOUT_1R disabled
1 = LINEOUT_1R enabled
Left channel LINEOUT2 enable
0 = LINEOUT_2L disabled
1 = LINEOUT_2L enabled
Right channel LINEOUT2 enable
0 = LINEOUT_2R disabled
1 = LINEOUT_2R enabled
PD, August 2008, Rev 4.0
DESCRIPTION
Production Data
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