Ordering number : ENA0321
Monolithic Linear IC
LA4902
Overview
Audio Output for TV application
10W BTL Monaural Power Amplifier IC
The LA4902 is a high-efficiency monaural BTL power amplifier.
The LA4902 holds the number of external components to a minimum and reduces power consumption (thermal loss) in the
operating range to one half that of earlier class B power amplifiers by using a signal following switching system for the
power supply to the amplifier output stage and by including a nonlinear amplifier in the signal system.
The use of a DIP-28H package obviates the need for a separate heat sink and can contribute to internal space savings in end
products.
Functions
•
High-efficiency 10W monaural BTL power amplifier (VCC = 14V, RL = 8Ω)
•
Provided in a DIP-28H package (no heat sink is required)
•
The number of required signal-following switching circuits has been held to a single circuit, thus reducing even further
the number of external components required.
•
The output is a fully analog signal, and no switching noise appears on the output lines.
•
Built-in standby switch (amplifier block/headphone block)
•
Built-in headphone amplifier : 1 input/2 output (VG = 6dB, PO = 60mW)
•
Built-in protection circuits (overvoltage and thermal protection circuits)
Specifications
Maximum Ratings
at Ta = 25°C
Parameter
Maximum supply voltage
Allowable power dissipation
Thermal resistance
Maximum junction temperature
Operating temperature
Storage temperature
Symbol
VCC max
Pd max
θj-c
Tj max
Topr
Tstg
No signal
With a infinity large heat sink
Conditions
Ratings
24
5
3
150
-25 to +75
-40 to +150
Unit
V
W
°C/W
°C
°C
°C
Any and all SANYO Semiconductor products described or contained herein do not have specifications
that can handle applications that require extremely high levels of reliability, such as life-support systems,
aircraft's control systems, or other applications whose failure can be reasonably expected to result in
serious physical and/or material damage. Consult with your SANYO Semiconductor representative
nearest you before using any SANYO Semiconductor products described or contained herein in such
applications.
SANYO Semiconductor assumes no responsibility for equipment failures that result from using products
at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition
ranges, or other parameters) listed in products specifications of any and all SANYO Semiconductor
products described or contained herein.
N1506 MS PC B8-4813 No.A0321-1/5
LA4902
Operating Conditions
at Ta = 25°C
Parameter
Recommended supply voltage
Recommended load resistance
Operating supply voltage range
Symbol
VCC
RL
VCC op
The range where the package Pd is not
exceeded
Conditions
Ratings
14
8
8 to 18
Unit
V
Ω
V
Electrical Characteristics
at Ta = 25°C
Parameter
Symbol
Conditions
min
[Amplifier Block] VCC = 14V, RL = 8Ω, f = 1kHz, Rg = 600Ω, See the specified board and circuit.
Quiescent current
Standby current
Voltage gain
Output power
Total harmonic distortion
Output noise voltage
Ripple rejection
Input resistance
Output offset voltage
Standby mode on voltage
ICCO
Ist
VG
PO
THD
VNO
SVRR1
Ri
VN offset
VST
Rg = 0
With the amplifier in, and the voltage applied
through a 10kΩ resistor
[Headphone Block] VCC = 14V, RL = 32Ω, f = 1kHz, Rg = 600Ω, See the specified board and circuit.
Voltage gain
Output power
Total harmonic distortion
Ripple rejection
Output noise voltage
VG
PO
THD
SVRR1
VNO
VO = 0dBm
THD = 10%
VO = 0dBm, LPF = 30kHz
Rg = 0, fR = 100Hz, VR = 0dBm, DIN AUDIO
Rg = 0, DIN AUDIO
75
5
50
6
60
0.025
85
0.01
0.04
0.05
7
dB
mW
%
dB
mV
VO = 0dBm
THD = 10%
PO = 1W, LPF = 30kHz
Rg = 0, DIN AUDIO
Rg = 0, fR = 100Hz, VR = 0dBm, DIN AUDIO
60
21
-200
3
28
8
Rg = 0
25
40
0
30
10
0.1
0.1
70
30
39
+200
VCC
0.4
0.3
80
10
32
mA
μA
dB
W
%
mV
dB
kΩ
mV
V
Ratings
typ
max
Unit
Package Dimensions
unit : mm (typ)
3147C
7
Pd max -- Ta
28
15
Allowable power dissipation, Pd max – W
6
12.7
11.2
8.4
R1.7
5
With a infinity large heat sink,
θjc=3˚C/W
Mounted on the
specified circuit board
3.5W
5W
0.4
4
1
20.0
26.75
14
3
Independent IC
2.5W
2.1W
2
1.5W
4.0
1
0
(1.81)
4.0
1.78
0.6
1.0
0
20
40
60
80
100
120
140
160
Ambient temperature, Ta – ˚C
SANYO : DIP28H(500mil)
No.A0321-2/5
LA4902
Block Diagram
L
100 F/10V
+
VG=6dB
HP OUT
*
0.047 F
HP IN
Headphone
R ch
10
+
47 F/25V
SW GND
1
Headphone
standby switch
Voltage
regulator
Ripple filter
28
+
1 F/10V
H/P Standby
2
Ripple filter
VCC
27
10k
D.C
+
+5V
3
26
+
47 F/25V
SW GND
4
Switching transistor
1A fT=30 to 50MHz
SW E
SW B
Amplifier
standby switch
Switching regulator block
AMP Standby
25
10k
+
+5V
5
Switching drive
H. L. S
24
6
Flywheel diode
200 H
SW OUT
2.2 F/25V
(OS capacitor)
+
2.2
VCC (SW)
B
A
*H.L.S
Higher
Level signal
Selector
23
ON TIME
7
On time muting circuit
22
+
22 F/6.3V
8
Impulse noise prevention circuit
21
PRE GND
+B
VCC
+
1000 F/25V
9
10
20
19
Input amplifier
1000pF
IN
11
2.2
*
0.1 F
OUT -
OUT +
*
0.1 F
2.2
Output amplifier
A
BE
EP
18
+
2.2 F/6.3V
12
B
17
+
2.2 F/6.3V
Beep amplifier
13
Output amplifier
Nonlinear amplifier
16
Power GND
14
Power GND
15
Power GND
*
Polyester film capacitor
No.A0321-3/5
LA4902
High-efficiency technologies used in the LA4902
1. Signal following switching method
The switching regulator technique is adopted in the
LA4902's power supply system used for the amplifier's
output stage. Power consumption is reduced significantly
by having the switching regulator's output voltage follow
the signal level. Furthermore, we were able to hold the
number of switching regulator circuits required to a single
circuit by use in combination with the nonlinear amplifier
technique described below. (See figure 1.)
Block Diagram
Switching regulator
Regulator output
+VCC
C
Nonlinear
amplifier
VIN
+
–
A
B
Amplifier's
output stage
[Figure 1]
2. Nonlinear amplifier technique
Nonlinear Amplifier I/O Characteristics
The LA4902 adopts a nonlinear amplifier in the amplifier
signal system that has the nonlinear characteristics shown
OUTPUT +
in figure 2. This system eliminates the need for the
switching regulator used for the low side signal by
lowering the midpoint voltage from the 1/2 VCC used in
normal amplifiers to about 2V.
–
This nonlinear amplifier is formed based on a differential
amplifier that has a symmetrical negative feedback circuit.
Although the BTL output stage positive phase and reverse
phase output waveforms have the compressed/expanded
half-wave waveform shown in figure 3, the synthesized
–
output waveform at the negative terminal is the same as
that output by earlier products.
[Figure 2]
+
INPUT
Output Waveforms
Regulator output
Output transistor
loss
Positive phase
output (A)
Midpoint voltage
GND
Reverse phase
output (B)
Between outputs
(A - B)
[Figure 3]
No.A0321-4/5
LA4902
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performance, characteristics, and functions of the described products in the independent state, and are
not guarantees of the performance, characteristics, and functions of the described products as mounted
in the customer's products or equipment. To verify symptoms and states that cannot be evaluated in an
independent device, the customer should always evaluate and test devices mounted in the customer's
products or equipment.
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and all semiconductor products fail with some probability. It is possible that these probabilistic failures
could give rise to accidents or events that could endanger human lives, that could give rise to smoke or
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so that these kinds of accidents or events cannot occur. Such measures include but are not limited to
protective circuits and error prevention circuits for safe design, redundant design, and structural design.
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Any and all information described or contained herein are subject to change without notice due to
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for the SANYO Semiconductor product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
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reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual
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This catalog provides information as of November, 2006. Specifications and information herein are subject
to change without notice.
PS No.A0321-5/5
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