Production Data
WM9715L
EAR SPEAKER OUTPUT – OUT3
Pin 37 (OUT3) has a buffer that can drive load impedances down to 16Ω. It can be used to:
•
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.
Note: OUT3 can only handle one of the above functions at any given time.
REGISTER
ADDRESS
BIT
15
LABEL DEFAULT
DESCRIPTION
16h
MUTE
1
Mute OUT3
OUT3
Control
1: Mute (Buffer OFF)
0: No Mute (Buffer ON)
Source of OUT3 signal
10:9
OUT3
SRC
00
00
inverse of HPOUTR
(for BTL ear speaker)
01
10
VREF (for capless headphone drive)
mono mix of both headphone channels
(for single-ended ear speaker)
11
inverse of MONOOUT
(for differential mono output)
7
ZC
0
Zero Cross Enable
0: Change gain immediately
1: Change gain only on zero crossings, or after
time-out
5:0
OUT3
VOL
000000
(0dB)
OUT3 Volume
000000: 0dB (maximum)
000001: -1.5dB
… (1.5dB steps)
011111: -46.5dB
1xxxxx: -46.5dB
Table 16 OUT3 Control
PD Rev 4.0 December 2007
31
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
