Ordering number : ENA0322
Monolithic Linear IC
LA4917H
Overview
Audio Output for TV application
High-Effciency Two-Channel 7W BTL
Power Amplifier ICs
The LA4917H is a high-effciency two-channel 7W BTL power amplifier IC. Increases in the number of external
components are held to a minimum by adopting both a signal-following type switching scheme in the amplifier’s output
stage power supply, and a nonlinear amplifier that has nonlinear characteristics in the signal system. The power dissipation
(thermal loss) in the actual operating range has been reduced to about 1/2 that of earlier class B amplifier ICs.
When used with the DIP-28H package, the IC dispenses with the heat sink and significantly contributes to space saving in
the end product case.
Features
•
High-efficiency two-channel 7W BTL power amplifier IC (V
CC
= 12V, R
L
= 8Ω)
•
Encapsulated in a DIP-28H package (heat sink free)
•
Requires only one signal-following type switching circuit, contributing to a reduction in the number of external
components
•
Provides analog outputs that generate no switching noise on the output lines
•
Built-in standby switches
•
Built-in protection circuits (overvoltage and thermal protection circuits)
Specifications
Maximum Ratings
at Ta = 25°C
Parameter
Maximum supply voltage
Allowable power dissipation
Maximum junction temperature
Operating temperature
Storage temperature
Symbol
VCC max
Pd max
Tj max
Topr
Tstg
No signal
Our recomnendation substrate
Conditions
Ratings
24
6.2
150
-25 to +75
-40 to +150
Unit
V
W
°C
°C
°C
Operating Conditions
at Ta = 25°C
Parameter
Recommended supply voltage
Recommended load resistance
Operating supply voltage range
Symbol
VCC
RL
VCC op
Conditions
Ratings
12
8
8 to 16
Unit
V
Ω
V
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 B8-9085 No.A0322-1/8
LA4917H
Electrical Characteristics
at Ta = 25°C, VCC (Pin 21), Pre VCC (Pin 20) = 12V, RL = 8Ω, f = 1kHz, Rg = 600Ω,
See the specified board and circuit.
Parameter
Quiescent current
Standby current
Voltage gain
Output power
Total harmonic distortion
Output noise voltage
Ripple rejection
Channel separation
Input resistance
Output offset voltage
Standby OFF voltage
Symbol
ICCO
Ist
VG
PO
THD
VNO
SVRR
CHsep
Ri
VN offset
VST
Rg = 0
Amplifier on
Amplifier off
*
: A DIN audio filter (20Hz to 20kHz) is used during measurement.
Conditions
min
Rg = 0, RL = Open
Amplifier off
VO = 0dBm
THD = 10%
PO = 1W, LPF = 30kHz
Rg = 0, DIN AUDIO*
Rg = 0, fR = 100Hz, VR = 0dBm, DIN AUDIO*
Rg = 10kΩ, VO = 0dBm, DIN AUDIO*
60
50
21
-120
2.5
0
27.2
5
35
Ratings
typ
60
0
29.2
7
0.09
0.05
75
60
30
39
+120
16
1.0
0.4
0.3
max
120
10
31.2
mA
µA
dB
W
%
mVrms
dB
dB
kΩ
mV
V
V
Unit
Package Dimensions
unit : mm (typ)
3233B
7.0
HEAT SPREADER
15.2
(6.2)
28
15
Pd max -- Ta
Four-layer circuit board
(with components mounted on the back side)
6.20
Allowable power dissipation, Pd max – W
6.0
5.0
Four-layer circuit board
(with no components mounted
on the back side)
4.35
3.55
3.05
2.61
2.13
1.83
3.72
(4.9)
10.5
7.9
0.65
Two-layer circuit board
4.0
(with components mounted
on the back side)
3.0
Two-layer circuit board
1
0.8
(0.8)
2.0
0.3
14
0.25
(with no components mounted
on the back side)
2.0
0
--25
(2.25)
2.45max
0
25
50
75
100
Ambient temperature, Ta – ˚C
2.7
0.1
SANYO : HSOP28H(375mil)
No.A0322-2/8
LA4917H
External Component Descriptions
C1 :
C2 :
This capacitor functions as a ripple filter. A value of 47µF is recommended.
This capacitor sets the amplifier startup wait time. A value of 22µF is recommended. (With this
value, the startup wait time will be about 0.7 seconds.) Although the startup wait time can be made
shorter by reducing the value of this capacitor, this can result in impulse noise appearing in the
output. We recommend always using a value larger than 10µF.
C3 and C5 :
Input capacitors. A value of 22µF is recommended. Note that if made variable, a value of 3.3µF or
lower should be used due to impulse noise considerations.
C4 :
This capacitor is the input reference amplifier capacitor, and the value must be the same as that of
C3 and C5.
C6 and R1 :
Smoothing capacitor for the switching regulator output. The LA4917H adopts a self-excited
oscillation switching regulator design. Since this capacitor influences the stability of the
self-excited oscillation, we recommend keeping the equivalent series resistance at high
frequencies low (roughly 3Ω or lower) and using a capacitor with good thermal characteristics.
For similar reasons, a value of 2.2Ω should be used for R1.
C7, C8, C9, and C10 : Oscillation prevention capacitors. We recommend using polyester film capacitors (Mylar
capacitor) with good thermal characteristics for these capacitors. These are used together with R2,
R3, R4, and R5.
C11 :
Switching regulator oscillation prevention capacitor. We recommend a value of 1000pF.
C12 :
Power supply capacitor
Tr1 and *RB :
This is an external switching transistor. Since the collector current has a peak of about 1.5A, we
recommend using a transistor in the fT = 30 to 50MHz range according to the current capacity
required. Note that if a transistor with an fT of 100MHz or higher is used, oscillation may be
induced in the switching waveform. Therefore in this case a base resistor, *RB, with a resistance of
about 10Ω must be added and the circuit adjusted so that oscillation does not occur.
L1 :
We recommend a coil inductance in the range 150 to 220µH.
D1 :
This is a flywheel diode that absorbs the coil energy. We recommend the use of a Schottky barrier
diode with a low VF.
Notes on the Switching Regulator
(Pins 22 to 24)
• The LA4917H includes a signal-following self-excitation switching regulator to hold power consumption to a
minimum. The self-excitation oscillation frequency when no signal is input will be in the range from about 130 to
170kHz.
• Transistor Tr1 is an external switching transistor.
We recommend using a device with IC = 2.5A and fT = 30
to 50MHz
If a transistor with an fT of 100MHz or higher is used,
oscillation may be induced in the switching waveform.
Therefore in this case a base resistor (RB, about 10Ω) must
be added and the circuit adjusted so that oscillation does not
occur.
• C6 is used to smooth the output of the switching regulator.
Since this capacitor influences the stability of the
self-excited oscillation, we recommend keeping the
equivalent series resistance at high frequencies low and
using a capacitor with good thermal characteristics. The
recommended value for this capacitor is 2.2µF.
Note that for similar reasons, a resistor with a value of 2.2Ω
should be used for R1.
• D1 is a flywheel diode that absorbs the coil energy. We
recommend the use of a Schottky barrier diode with a low
VF.
24
SW B
*RB
10Ω
Tr1
Switching
Transistor
I C =2.5A
f T = 30 to 50MHz
23
SW E
L1
180µH
C6
2.2µF
/25V
R1
2.2
Ω
D1
Flywheel
Diode
22
SW OUT
No.A0322-5/8
GD32 MCU
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