LA4628 ®
ON Semiconductor“?
O0808 MS JK/92900RM(OT) No.6632-1/8
http://onsemi.com
Semiconductor Components Industries, LLC, 2013
May, 2013
LA4628
Overview
The LA4628 is a 2-channel general-purpose BTL audio power amplifier provided in a miniature package. It was
designed for the best possible audio quality and features an extended low band roll-off frequency provided by a
newly-developed NF circuit that does not require an external capacitor. Furthermore, crosstalk, which can cause
muddiness in the audio output, has been significantly reduced by both circuit and wiring pattern improvements. Thus
this amplifier can provide powerful lows and clear highs.
Note that this device is pin compatible with the 13.5W×2-channel LA4625, and allows end products differentiated by
their power rating to share the same printed circuit board.
Features
• Total output : 20W+20W (at VCC = 13.5V, RL = 4Ω, THD = 10%)
• High-fidelity design (fL < 10Hz, fH = 130kHz)
• Extremely low impulse noise levels
• An arbitrary amplifier startup time can be set up with external components.
• Full complement of built-in protection circuits (includes circuits that protect against shorting to VCC, shorting to
ground, load shorting, overvoltages and excessive temperatures)
Specifications
Maximum Ratings at Ta = 25°C
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage VCC max No signal 24 V
Maximum output current IO peak Per channel 4A
Allowable power dissipation Pd max With an arbitrarily large heat sink 32.5 W
Operating temperature Topr -20 to +85 °C
Storage temperature Tstg -40 to +150 °C
Orderin
g
number : EN6632A
Monolithic Linear IC
20W 2-Channel BTL Power Amplifier
for General Audio
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating
Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
rm spawn
4c
mm 7,
E 3 ’
um:
22
S‘PMHZ
LA4628
No.6632-2/8
Operating Conditions at Ta = 25°C
Parameter Symbol Conditions Ratings Unit
Recommended supply voltage VCC 13.5 V
Recommended load resistance range RL op 4 to 8 Ω
Allowable operating supply voltage range VCC op 9 to 20 V
Note : With VCC, RL, and the output level in ranges such that the Pd max for the heat sink used is not exceeded.
Electrical Characteristics at Ta = 25°C, VCC = 13.5V, RL = 4Ω, f = 1kHz, Rg = 600Ω
Parameter Symbol Conditions Ratings Unit
min typ max
Quiescent current ICCO With Rg = 0 and RL open. 70 130 250 mA
Standby mode current drain Ist Standby mode (amplifier off), with no power
supply capacitor.
10 60 μA
Voltage gain VG V
O = 0dBm 38 40 42 dB
Total harmonic distortion THD PO = 1W, Filter = FLAT 0.06 0.2 %
Output power PO1 VCC = 13.5V, THD = 10%, RL = 4Ω 16 20 W
PO2 VCC = 16.5V, THD = 10%, RL = 4Ω 30 W
Output offset voltage VN offset Rg = 0 -300 +300 mV
Output noise voltage VNO Rg = 0, BPF = 20Hz to 20kHz 0.1 0.5 mV
Ripple rejection ratio SVRR Rg = 0, V
R
= 0dBm, fR = 100Hz 40 50 dB
Channel separation CHsep Rg = 10kΩ, VO = 0dBm 50 60 dB
Input resistance Ri 21 30 39 KΩ
Standby pin applied voltage VST Amplifier on
(applied through an external 10kΩ resistor)
2.5 VCC V
Package Dimensions
unit : mm (typ)
3113B
0
Pd max -- Ta
-20
35
25
30
15
20
10
5
200 40 60 80 100 120 140 160
θf
=
3˚C/W
θf
=
4˚C/W
θf
=
7˚C/W
θjc
=
2˚C/W
Νο Fin
θf
=
10˚C/W
32.5
20.83
13.9
10.4
3.1
Infinite heat sink
Allowable power dissipation, Pd max -- W
Ambient temperature, Ta -- ˚C
AI heat sink Mounting
torque 39N cm Flat
washer Silicone grease
applied
LA4628
No.6632-3/8
Block Diagram
0.1μF 0.1μF
R4
C9**
C8**
R5
2.2Ω2.2Ω
RL
4Ω
RL
4Ω
-OUT2
+OUT2
–
+
Standby
SW
OFF
RIPPLE
FILTER
+
BIAS
CIRCUIT
STANDBY
SW
POP NOISE
PREVENTION
CIRCUIT
PREDRIVER
PREDRIVER
POWER
POWER
LOAD SHORT
PROTECTOR
OUTPUT PIN TO VCC
SHORT PROTECTOR
OUTPUT PIN TO VCC
SHORT PROTECTOR
OUTPUT PIN TO GND
SHORT PROTECTOR
OUTPUT PIN TO GND
SHORT PROTECTOR
PREDRIVER
PREDRIVER
POWER
POWER
OVER VOLTAGE /
SURGE PROTECTOR
THERMAL
SHUT DOWN
LOAD SHORT
PROTECTOR
VCC
+
+
ON R1
10KΩ
+5V
C4
2.2μF
10V
33μF
10V
0.47μF
10V
2.2μF
10V
C1
100μF/16V VCC
C5
2200μF
25V
+
-OUT1
+OUT1
–
+
POWER
GND2
++
C3 C10
**
(POLYESTER FILM
CAPACITOR)
+
–IN
C2
PRE GND
IN2
C3
Sets the amplifier starting time
(Approximately 0.6 seconds when 33μF)
C10
Impulse noise reduction
(Note : The device’s ability to withstand shorting
to VCC or shorting to ground when VCC is around
16V may be reduced as the value of this
capacitor is increased. We recommend 0.47μF.)
POWER
GND1
14
2
1
3
4
6
7
5
11
12
13
0.1μF 0.1μF
R2
C7**
C6**
R3
2.2Ω2.2Ω
9
10
8
+
–IN
LA4628
No.6632-4/8
Pin Voltages
VCC = 13.5V, with 5V applied to STBY through a 10kΩ resistor, RL = 4Ω, Rg = 0
Pin No. 1 2 3 4 5 6 7
Pin name IN1 DC PRE–GND STBY ON TIME IN2 POP
Pin voltage 1.55V 6.63V 0V 3.21V 2.32V 1.55V 2.07V
Pin No. 8 9 10 11 12 13 14
Pin name +OUT2 -OUT2 PWR–GND +OUT1 PWR–GND -OUT1 VCC
Pin voltage 6.6V 6.5V 0V 6.5V 0V 6.6V 13.5V
External Components
C1 and C4 : Input capacitors. A value of 2.2µF is recommended. Determine the polarity based on the DC
potential of the circuit connected directly to the LA4628 front end. Note that the low band response
can be adjusted by varying fL with the capacitors C1 and C4.
C2 : Decoupling capacitor (ripple filter)
C3 : Sets the amplifier starting time, which will be approximately 0.6 seconds for a value of 33µF.
The starting time is proportional to the value of this capacitor, and can be set to any desired value.
C5 : Power-supply capacitor
C6, C7, C8, and C9
: Oscillation prevention capacitors. Use polyester film capacitors (Mylar capacitors) with excellent
characteristics. (Note that the series resistors R2, R3, R4, and R5 are used in conjunction with these
capacitors to achieve stable amplifier operation.) A value of 0.1µF is recommended.
C10 : Impulse noise reduction capacitor. A value of 0.47µF is recommended. Caution is required when
selecting the value for this capacitor, since increasing its value influences the operation of the
circuits that protect against shorting the amplifier output pins to VCC or to ground when higher VCC
voltages (approximately 16V or higher) are used.
R1 : Standby switch current limiting resistor. A value of 10kΩ is recommended when a voltage in the
range 2.5 to 13.5V will be applied as the standby switching voltage. Note that this resistor is not
optional : it must be included.
IC Internal Characteristics and Notes
1. Standby function
• Pin 4 is the standby switch. A voltage of 2.5V
or higher must be applied through an external
resistor to turn the amplifier on.
• If a voltage of over 13.5V will be applied as the
standby mode switching voltage, use the following
formula to determine the value of R1 so that the
current entering at pin 4 remains under 500µA.
R1 = <applied voltage>−1.4 −10kΩ
500μA
2. Muting function
• Pin 5 connects the capacitor that determines the starting time to prevent impulse noise. It can also be used to mute
the amplifier output by shorting pin 5 to ground. When this function is used, the recovery time depends on C3.
4
R1
10kΩ
500μA or lower
About 1.4V
(2VBE)
Pin 4 Internal Equivalent Circuit
Applied standby
voltage
LA4628
No.6632-5/8
3. Impulse noise improvements
• While the LA4628 achieves a low level of impulse noise, if even further reductions in impulse noise at power on/off
(and when switching into or out of standby mode) a 0.47µF capacitor may be inserted between pin 7 and the PRE
GND pin (pin 3). (Pin 7 is the output amplifier bias pin. Since the ability to withstand shorting the output pins to
VCC or ground is reduced for supply voltages over 16V if the pin 7 capacitance is large, we recommend a value of
0.47µF or lower for this capacitor.)
4. Protection circuits
• Due to the system structure of the protection circuit for shorts to VCC or ground, if there is a DC resistance between
the amplifier output pins and ground, the protection circuit may operate when power is first applied and the
amplifier may fail to turn on. The basic design approach we recommend is not to adopt any designs in which there is
a DC resistance between the amplifier outputs and ground.
• The LA4628 includes a built-in thermal protection circuit to prevent the IC from being damaged or destroyed if
abnormally high temperatures occur. This thermal protection circuit gradually reduces the output if the IC junction
temperature (Tj) reaches the range 170 to 180°C due to inadequate heat sinking or other problem. If the temperature
falls, the amplifier will restart automatically.
• The LA4628 also includes other protection circuits. Use of these circuits also requires care during end product
design and testing.
5. Other notes
• The LA4628 is a BTL power amplifier. When testing this device, the ground systems for the test equipment
connected to IC inputs, and that for the test equipment connected to IC outputs, must be isolated. Do not use a
common ground.
Printed Circuit Pattern
(copper foil side)
GND
GND
VCC
GND
C5
R2 C6
-OUT1
C1
14
LA4628
1
+
+
+
++
+
IN1
IN2
C3
C2
R1
C4
C10
STB
+OUT1
-OUT2
+OUT2
R3 C7
R4 C8
R5 C9
LA4628
No.6632-6/8
15 16 17 18
0
25
PO -- VCC
6789 1110 12 13 14
10
5
15
30
35
20
40
0.01
PO -- VIN
1.0 23 57
10 23 57
100 23 57
1k
2
3
5
7
0.1
1.0
2
3
5
7
10
2
3
5
7
100
2
3
5
7
0
25
PO -- f
THD -- PO
10 100 1k 10k 100k
23 57 3 57235723572
5
10
15
20
-10
-8
-6
-4
-2
0
2f Response
10 23 57
100 23 57
1k 23 57
10k 100k
23 57
0.01
10
7
5
3
2
7
5
3
2
7
5
3
2
0.1 1.0
23 57 10
23 57 100
23 57
1.0
0.1
0.01
2
3
5
7
0.1
2
3
5
7
1.0
10
2
3
5
7
THD -- PO
0.1 23 57
1.0 23 57
10 100
23 57
-10
-40
-50
-60
-70
-80
-90
0.01
0.1
2
3
5
7
1.0
2
3
5
7
10
2
3
5
7
THD -- f
10 23 57
100 23 57
1k 23 57
10k 100k
23 57
CHsep -- f
10 100
23 57 1k
23 57 10k
23 57 100k
23 57
-30
-20
VCC
=
13.5V
RL
=
4Ω
Rg
=
10kΩ
VO = 0dBm
f
=
1kHz
Rg
=
600Ω
THD
=
10%
VCC
=
13.5V
RL
=
4Ω
f
=
1kHz
VCC
=
13.5V
RL
=
4Ω
Rg = 600Ω
VO = 0dBm at 1kHz
VCC
=
13.5V
RL
=
6Ω
Rg = 600Ω
RL
=
4Ω
RL
=
6Ω
VCC
=
13.5V
RL
=
4Ω
Rg
=
600Ω
VCC
=
13.5V
RL
=
4Ω
Rg
=
600Ω
VCC
=
13.5V
RL
=
4Ω
RO
=
1W
THD
=
10%
THD
=
1%
10kHz
100Hz
1kHz
THD
=
3%
10kHz
100Hz
1kHz
0
Input voltage, VIN -- mVrms
Output power, PO -- W
Supply voltage, VCC -- V
Frequency, f -- Hz Frequency, Ta -- °C
Response -- dB
Output power, PO -- W Output power, PO -- W
Frequency, f -- Hz
Output power, PO -- W
Output power, PO -- W
Total harmonic distortion, THD -- %
Total harmonic distortion, THD -- %
Total harmonic distortion, THD -- %
Frequency, f -- Hz
Channel separation, CHsep -- dB
CH1
2
CH2
1
/‘—
/:fi
/§/
LA4628
No.6632-7/8
VNO -- Rg
2
100 357 2
1k 357 2
10k 100k
357
7
5
3
2
1.0
7
5
3
2
0.1
0.01
SVRR -- VCC
SVRR -- fR
7 9 11 13 15 17 19 21 235
0
-20
-40
-60
-80
-100
-120
-100
SVRR -- VCCR
Pd -- PO (RL
=
4Ω)Pd -- PO (RL
=
6Ω)
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
-80
-60
-40
-20
-100
-80
-60
-40
-20
0
10 23 57
100 23 57
1k 23 57
10k 100k
23 57
0
32
28
24
20
16
12
0.1 1.0
23 57 10
23 57 100
23 57
32
28
24
20
18
12
8
4
0
0.1 1.0 10 100
23 57 23 57 23 57
0
1
2
3
4
5
6
ICC -- PO
0.1 23 57
1.0 23 57
10010
23 57
VCC
=
13.5V
RL
=
4Ω
DIN AUDIO
Rg
=
0
fR
=
100Hz
VCCR
=
0dBm
VCC
=
13.5V
RL
=
4Ω
Rg
=
0
VCCR
=
0dBm
VCC
=
13.5V
RL
=
4Ω
Rg
=
0Ω
RL
=
4/6Ω
Rg
=
600Ω
f
=
1kHz
Pd(16.5V)
RL
=
4Ω
RL
=
6Ω
Pd(13.5V)
100Hz OUT1
3kHz OUT1
3kHz OUT2
100Hz OUT2
Pd (16.5V)
Pd (13.5V)
VO
VCCR
OUT1
OUT2
OUT2
OUT1
Supply voltage, VCC -- V
Ripple rejection ratio, SVRR -- dBRipple rejection ratio, SVRR -- dB
Signal source resistance, Rg -- Ω
Power supply ripple, VCCR -- Vrms Ripple frequency, fR -- Hz
Output power, PO -- W/CH Output power, PO -- W/CH
Output noise voltage, VNO -- mVrms
Ripple rejection ratio, SVRR -- dB
Power dissipation, Pd -- W
Power dissipation, Pd -- W
Current drain, ICC -- A
Output power, PO -- W/CH
RL
=
6Ω
Rg
=
600Ω
f
=
1kHz
Calculated at
Pd
=
(VCC × ICC) - (2PO)
Calculated at SVRR
=
20log
RL
=
4Ω
Rg
=
600Ω
f
=
1kHz
Calculated at
Pd
=
(VCC × ICC) - (2PO)
LA4628
PS No.6632-8/8
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