SA7264
2-CH AUDIO POWER AMPLIFIER(25W X2 )
DESCRIPTION
The SA7264 is a monolithic integrated circuit in HSIP package, intended
for use as dual audio frequency class AB amplifier.
FEATURES
* Wide supply voltage range up to 50V ABS MAX.
* Split supply operation.
* High output power: 25 + 25W @ THD=10%,R
L
=8 ,V
S
=±20V
* Mute/stand-by function.
* Few external components.
* Short circuit protection.
* Thermal overload protection.
HSIP-11
HSIP-8
HSIP-15
APPLICATIONS
* Hi-Fi music centers
* Stereo TV sets
ORDERING INFORMATION
Part No.
SA7264
SA7264A
SA7264B
Package
HSIP-8
HSIP-15
HSIP-11
BLOCK DIAGRAM
Note:
Figures for the SA7264.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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REV:1.1
2006.05.25
Page 1 of 13
SA7264
ABSOLUTE MAXIMUM RATING
Characteristics
DC Supply Voltage
Output Peak Current
(Internally Limited)
Power Dissipation
Tcase=70°C
Storage And Junction
Temperature
Supply voltage to guarantee
short-circuit protection
Thermal Resistance From
Junction To Case (Max)
normal.
Symbol
V
s
I
o
P
tot
T
stg
, T
j
V
s(sc)
R
t
h(j-c)
Ratings
50
4.5
30
-40~+150
±18(*)
2
Unit
V
A
W
°C
V
°C/W
(*)Maximum supply voltage to guarantee short-circuit to
±
Vs is
±18V,
and to GND short-circuit protection is
ELECTRICAL CHARACTERISTICS
(Refer to the test circuit, V
s
±20V;
R
L
=8Ω; R
s
=50Ω; f=1KHz; T
amb
=25°C,
unless otherwise specified.)
Characteristics
Supply Range
Total Quiescent Current
Music Output Power(*)
Symbol
V
s
I
q
P
o
THD=10%;R
L
=8Ω;
V
s
=±22.5V
THD=10%;
Output Power
P
o
R
L
=8Ω;
V
s
=±16V; R
L
=4Ω
THD=1%;
Output Power
P
o
R
L
=8Ω;
V
s
=±16V; R
L
=4Ω
R
L
=8Ω; P
o
=1W; f=1kHz
R
L
=8Ω;
P
o
=0.1~15W;
Total Harmonic Distortion
THD
f=100Hz~15kHz
R
L
=4Ω; P
o
=1W; f=1kHz
R
L
=4Ω; V
s
=±16V;
P
o
=0.1~12W;
f=100Hz~15kHz
Cross Talk
Slew Rate
Closed Loop Voltage Gain
CT
SR
G
V
29
f=1kHz
f=10kHz
70
60
10
30
31
dB
dB
V/µs
dB
0.03
1
%
%
20
20
0.02
0.5
W
W
%
%
20
25
25
W
W
Test conditions
Min.
±5
80
32
Typ.
Max.
±22.5
130
Unit
V
mA
W
(To be continued)
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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REV:1.1
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SA7264
(Continued)
Characteristics
Voltage Gain Matching
Total Input Noise
Input Resistance
Supply Voltage Rejection
(each channel)
Thermal Shut-down Junction
Temperature
Mute Function [ref: +Vs]
Mute /Play Threshold
Mute Attenuation
Stand-by Function [ref: +Vs]
Stand-by /Mute Threshold
Stand-by Attenuation
Quiescent Current @ St-by
Note:
Symbol
∆GV
eN
R
i
SVR
Tj
Test conditions
A curve
f=20Hz~22kHz
Min.
Typ.
0.2
2.5
3.5
Max.
Unit
dB
µV
8
µV
kΩ
dB
°C
15
fr=100Hz; V
ripple
=0.5V
rms
20
60
145
V
TMUTE
AM
V
TST-BY
A
ST-BY
I
q ST-BY
-7
60
-3.5
-6
90
-2.5
110
3
-5
V
dB
-1.5
V
dB
mA
* Music Output Power is the maximal power which the amplifier is capable of producing across the rated load
resistance (regardless of non linearity) 1 sec after the application of a sinusoidal input signal of frequency 1KHz.
According to this definition, the method of measurement comprises the following steps:
1) Set the voltage supply at the maximum operating value -10%
2) Apply a input signal in the form of a 1KHz tone burst of 1 sec duration; the repetition period of the signal pulses
is > 60 sec
3) The output voltage is measured 1 sec from the start of the pulse
4) Increase the input voltage until the output signal show a THD = 10%
5) The music power is then Vout
2
/RL, where Vout is the output voltage measured in the condition of point 4) and
R1 is the rated load impedance
The target of this method is to avoid excessive dissipation in the amplifier.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
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REV:1.1
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SA7264
PIN CONFIGURATION
Note: Tab connected to –Vs.
PIN DESCRIPTION
Pin No.
HSIP-8
8
6
1
3
7
2
5
4
HSIP-11
11
7
2
4
9
3
1, 6
5
8, 10
HSIP-15
13
10
3
6
12
5
2, 8
7
1, 4, 9, 11,
14, 15
Pin name
IN 1
IN2
OUT 1
OUT 2
GND
+Vs
-Vs
MUTE / ST-
BY
NC
Input 1
Input 2
Output1
Output2
Ground
Positive power
Negative power
Mute /stand-by function
Not connected
Pin description
FUNCTION DESCRIPTION
MUTE STAND-BY FUNCTION
The PIN mute/st_by controls the amplifier status by two different thresholds, referred to +Vs.
Ø
Ø
Ø
When Vmute/st_by higher than +Vs - 2.5V the amplifier is in Stand-by mode and the final stage
generators are off
When Vmute/st_by is between +Vs - 2.5V and +Vs- 6V the final stage current generators are switched
on and the amplifier is in mute mode
When Vmute/st_by is lower than +Vs - 6V the amplifier is play mode.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: www.silan.com.cn
REV:1.1
2006.05.25
Page 4 of 13
SA7264
POWER DISSIPATION AND HEAT SINKING
The SA7264 must always be operated with a heat sink, even when it is not required to drive a load. The idling
current of the device is 80mA, so that on a
±20V
power supply an unloaded SA7264 must dissipate about 3W of
power. The 54°C/W junction-to-ambient thermal resistance of a HSIP-11 package would cause the die
temperature to rise 162°C above ambient, so the thermal protection circuitry will shut the amplifier down if
operation without a heat sink is attempted.
In order to determine the appropriate heat sink for a given application, the power dissipation of the SA7264 in
that application must be known. When the load is resistive, the maximum average power that the IC will be
required to dissipate is approximately:
PD(MAX)=Vs
2
/π
2
RL+PQ
Where V
S
is the total power supply voltage across the SA7264, RL is the load resistance PQ is the quiescent
power dissipation of the amplifier. The above equation is only an approximation which assume an “
ideal”class B
output stage and constant power dissipation in all other parts of the circuit. The curves of “
Power Dissipation vs.
Power Output”give a better representation of the behaviour of the SA7264 with various power supply voltages
and resistive loads. As an example, if the SA7264 is operated on a
±20V
power supply with a resistive load of 8Ω,
it can develop up to 23W of internal power dissipation. If the die temperature is to remain below 150°C for
ambient temperatures up to 50°C, the total junction-to-ambient thermal resistance must be less than:
(150°C 50°C)/23W
4.3°C/W
Using Rth(j-c) = 2°C /W, the sum of the case-to-heat-sink interface thermal resistance and the heat-sink-to-
ambient thermal resistance must be less than 2.3°C/W. The case-to-heat-sink thermal resistance of the HSIP-11
package varies with the mounting method used. A metal-to-metal interface will be about 1°C /W if lubricated, and
about 1.2°C /W if dry.
If a mica insulator is used, the thermal resistance will be about 1.6°C /W lubricated and 3.4°C /W dry. For this
example, we assume a lubricated mica insulator between the SA7264 and the heat sink. The heat sink thermal
resistance must then be less than:
4.3°C/W-2°C/W-1.6°C/W
0.7°C/W
This is a rather large heat sink and may not be practical in some applications. If a smaller heat sink is required
for reasons of size or cost, there is an alternative. The heat sink can be isolated from the chassis so the mica
washer is not needed. This will change the required heat sink to a 1.3°C /W unit if the case-to-heat-sink interface
is lubricated.
The thermal requirements can become more difficult when an amplifier is driving a reactive load. For a given
magnitude of load impedance, a higher degree of reactance will cause a higher level of power dissipation within
the amplifier. As a general rule, the power dissipation of an amplifier driving a 60º reactive load (usually
considered to be a worst-case loudspeaker load) will be roughly that of the same amplifier driving the resistive
part of that load. For example, a loudspeaker may at some frequency have an impedance with a magnitude of 8Ω
and a phase angle of 60º. The real part of this load will then be 4Ω, and the amplifier power dissipation will
roughly follow the curve of power dissipation with a 4Ω load.
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: www.silan.com.cn
REV:1.1
2006.05.25
Page 5 of 13
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