wm9712l Wolfson Microelectronics plc, wm9712l Datasheet - Page 30

• Manufacturer Part Number: wm9712l
• Description: Ac?97 Audio And Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

WM9712L
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EAR SPEAKER OUTPUT – OUT3
Pin 37 (OUT3) has a buffer that can drive load impedances down to 16Ω. It can be used to:
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•
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Note: OUT3 can only handle one of the above functions at any given time.
Table 16 OUT3 Control
16h
OUT3
Control
REGISTER
ADDRESS
Drive an ear speaker (phone receiver). The speaker can be connected differentially
between OUT3 and HPOUTL, or in single-ended configuration (OUT3 to HPGND). The
ear speaker output is produced by the headphone mixer. The right signal must be
inverted (OUT3INV = 1), so that the left and right channel are mixed to mono in the
speaker [L–(-R) = L+R].
Eliminate the DC blocking capacitors on HPOUTL and HPOUTR. In this configuration,
OUT3 produces a buffered midrail voltage (AVDD/2) and is connected to the headphone
socket’s ground pin (see “Applications Information”)
Produce the inverse of the MONOOUT signal, for a differential mono output.
15
10:9
7
5:0
BIT
MUTE
OUT3
SRC
ZC
OUT3
VOL
LABEL
DEFAULT
1
00
0
000000
(0dB)
Mute OUT3
1: Mute (Buffer OFF)
0: No Mute (Buffer ON)
Source of OUT3 signal
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings, or after
time-out
OUT3 Volume
000000: 0dB (maximum)
000001: -1.5dB
… (1.5dB steps)
011111: -46.5dB
1xxxxx: -46.5dB
00
01
10
11
inverse of HPOUTR
(for BTL ear speaker)
VREF (for capless headphone drive)
mono mix of both headphone channels
(for single-ended ear speaker)
inverse of MONOOUT
(for differential mono output)
DESCRIPTION
PD Rev 4.5 August 2006
Production Data
30