ICs for Audio Common Use
AN12942B
Audio signal processing IC for notebook PC
Overview
AN12942B is an one-chip IC for the stereo speakers which can output 1 W by 8
Ω,
headphone amplifiers, line amplifiers, and
electronic volumes.
The AGC circuit is built-in to prevent the resonance or the vibration by the speaker’s energy and the clipping distortion what is
called "broken up sound".
Also the AN12942B is built-in power saving on/off function automatically detecting input signal to save the power of speaker
amplifier.
Features
•
Speaker amplifier
1 W
×
2-channel: 8
Ω,
V
CC
=
5 V
•
Built-in AGC circuit
Prevention of the resonance or the vibration due to the speaker and the clipping distortion by AGC at excessive input signal
(with AGC on/off switch).
•
Built-in automatic power saving function.
It detects input signals and switches on/off (with the on/off switch for the auto power saving).
•
Built-in headphone amplifier and line amplifier
Applications
•
Notebook PC
Package
•
Dual surface implementing package (HSOP056-P-0300A)
Type
•
Silicon monolithic bipolar IC
Publication date: June 2003
SDC00047AEB
1
AN12942B
Application circuit example
Out-L-ch. (Line)
−9.17
dBV
1
µF
29
30
31
Line
mute
−10
dBV
0.47
µF
28
27
GND
26
25
24
+
+
23
22
21
EVR
EVR
20
19
Offset
cancel
V
REF
Offset
cancel
18
10
µF
0. 1
µF
10
µF
0.47
µF
−10
dBV
1.1 times
1.1 times
In-L-ch. (Line,HP)
In-R-ch. (Line,HP)
Out-R-ch. (Line) 1
µF
1
µF
Line mute
STBY
V
CC
Beep in
−9.17
dBV
1 MΩ
Switch B
0.47
µF
32 Standby
33
34
35
Switch B-2
Switch B-1
Switch A-3
Switch A-2
Switch A-1
BV
REF
EVRCTL
Switch A
1
µF
1
µF
HP power save
HP mute
100
µF
100
µF
220 k
36
37
GND
38
6
dB
−4
dBV
39
−4
dBV
40
6
dB
41
GND
42
Power
save
1
µF
10
µF
−13
dBV
Save
CTL
PRI
Charge 17
V
CC
16
GND
15
14
13
12
11
10
GND
9
20 kΩ
0. 47
µF
−2
dBV
−2
dBV
10
µF
43
−3
dB
44
−13
dBV
−3
dB
45
46
47
GND
48
49
V
REF
(SP)
0. 47
µF
0. 47
µF
0. 47
µF
2 200 pF
AGC
AGC
Offset
cancel
Det.
Signal
det.
Signal automatic
detection function
on/off
V
CC
V
CC
SP save
on/off
0.47
µF
0.47
µF
1
µF
100 kΩ 1
µF
Offset
cancel
0.47
µF
AGC on1/on2/off
Control
Mute
Save
CTL
Mute
8
7
SP GND
6
5
330 kΩ
50
SP GND
51
52
53
54
55
56
14
dB
14 dB
−2
dBV
8
Ω
L-ch. out
−2
dBV
Power
save
4
3
8
Ω
R-ch. out
14
dB
V
CC
_SP
14 dB
V
CC
_SP
2
1
10
µF
Supply voltage 5 V
SDC00047AEB
2
AN12942B
Pin Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Pin name
V
CC
_SP
SP_OUT_R+
SP_OUT_R+
SP_OUT_R−
SP_OUT_R−
GND_SP
DETECT_CAP
AGC_LV
GND
AGC_CAP
DETECT_IN
DAMP_OUT
OFFSET_HPR
OFFSET_HPL
GND
V
CC
PRI_V
V
REF
_IN
EVR_CTL
BV
REF
Switch A-1
Switch A-2
Switch A-3
Switch B-1
Switch B-2
GND
INPUT_R
INPUT_L
LINEOUT_L
LINEOUT_R
LINE_MUTE
STANDBY
Switch B
BEEP_IN
Type
V
CC
Output
Output
Output
Output
GND
Input
TTL input
GND
Input
Input
Output
Input
Input
GND
V
CC
Input
Input
TTL input
Input
Output
Output
Output
Output
Output
GND
Input
Input
Output
Output
TTL input
TTL input
TTL input
Input
V
CC
_SP
R-channel
Description
Speaker amplifier R-channel positive phase output (+)
Speaker amplifier R-channel positive phase output (+)
Speaker amplifier R-channel negative phase output (−)
Speaker amplifier R-channel negative phase output (−)
GND_SP R-channel
Demodulation pin for signal automatic detection
AGC-on level control
GND
AGC demodulation pin
Signal input for signal automatic detection
Signal automatic detection mix amplifier output
Offset cancel pin for headphone R-channel
Offset cancel pin for headphone L-channel
GND
V
CC
PRI-charge level pin
V
REF
EVR control for speaker and headphone
Bias in
Switch A-1
Switch A-2
Switch A-3
Switch B-1
Switch B-2
GND
R-channel input
L-channel input
Line L-channel output
Line R-channel output
Line mute on/off control
Standby on/off control
Switch B
Input for beep signal
SDC00047AEB
3
AN12942B
Pin Descriptions (continued)
Pin No.
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
Pin name
Switch A
HP_SAVE
HP_MUTE
GND
HP_OUT_L
HP_OUT_R
V
CC
GND
V
REF
_SP
SP_IN_R
SP_IN_L
OFFSET_SPR
OFFSET_SPL
GND
DETECT_ON
SP_SAVE
GND_SP
SP_OUT_L−
SP_OUT_L−
SP_OUT_L+
SP_OUT_L+
V
CC
_SP
Type
TTL input
TTL input
TTL input
GND
Output
Output
V
CC
GND
Input
Input
Input
Input
Input
GND
TTL input
TTL input
GND
Output
Output
Output
Output
V
CC
Switch A
Headphone power save control
Headphone mute on/off control
GND
Headphone amplifier L-channel output
Headphone amplifier R-channel output
V
CC
GND
V
REF
_SP
Speaker amplifier R-channel input
Speaker amplifier L-channel input
Offset cancel pin for speaker R-channel
Offset cancel pin for speaker L-channel
GND
Signal automatic detection on/off control
Speaker power save control
GND_SP L-channel
Speaker amplifier L-channel negative phase output (−)
Speaker amplifier L-channel negative phase output (−)
Speaker amplifier L-channel positive phase output (+)
Speaker amplifier L-channel positive phase output (+)
V
CC
_SP L-channel
Description
SDC00047AEB
4
AN12942B
Absolute Maximum Ratings
A
No.
1
2
3
4
5
Parameter
Supply voltage
Supply current
Power dissipation
Storage temperature
Operating ambient temperature
Symbol
V
CC
V
CC
_SP
I
CC
P
D
T
stg
T
opr
Rating
5.75
5.75
517
−55 ∼ +150
−20 ∼ +75
Unit
V
A
mW
ºC
ºC
Note
*1
*2
*3
*3
Note) *1: The values under the condition not exceeding the above absolute maximum ratings and the power dissipation.
*2: When using this IC, referring to the technical data in page 17, observe the power dissipation characteristic curve.
Be sure to use the IC so that the power dissipation of the IC without heat sink will not exceed 517 mW at T
a
=
75ºC.
*3: Except for the operating ambient temperature and storage temperature, all ratings are for T
a
=
25ºC.
Operating Supply Voltage Range
Parameter
Operating supply voltage range
Symbol
V
CC
V
CC
_SP
Range
4.50
∼
5.50
4.50
∼
5.50
Unit
V
Note
*
Note) *: The values under the condition not exceeding the above absolute maximum ratings and the power dissipation.
SDC00047AEB
5
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