semiconductor fa386p/f
SEMICONDUCTOR
FA386P/F
TEC HNIC AL D ATA
Low Voltage Audio Power Amplifier
W
D
G
L
The FA386 is a power amplifier designed for use in low voltage consumer
application. The gain is internally set to 20 to keep external part count low,
but the addition of an external resistor and capacitor between pins 1 and
8 will increase the gain to any value up to 200.
The inputs are ground referenced while the output is automatically biased
to one half the supply voltage. The quiescent power drain is only 24 milliwatts
when operating from a 6 volt supply,
making the FA386 ideal for battery operation.
H
General Description
P
d
DIM MILLIMETERS
_0 2
A
9 6+
_0 2
B
6 45 +
_0 1
D
1 52 +
_0 1
d
0 46 +
G
0 50 MIN
_0 3
H
3 8+
_0 3
L
3 3+
P
2 54
T
0 25+0 1/-0 05
7 62
W
Q
0 - 15
A
8
5
1
4
B
Features
● Battery operation
● Minimum external parts
● Wide supply voltage range: 4V–12V or 5V–18V
● Low quiescent current drain: 4 mA
● Voltage gains from 20 to 200
● Ground referenced input
● Self-centering output quiescent voltage
● Low distortion
● Available in DIP-8 , SOP-8 package
Q
T
DIP-8
T
L
G
P
D
1
4
B
5
2
8
B
A
1
● AM-FM radio amplifiers
● Portable tape player amplifiers
● Intercoms
● TV sound systems
● Line drivers
● Ultrasonic drivers
● Small servo drivers
● Power converters
H
Applications
Schematic Diagram
DIM
A
B1
B2
D
G
H
L
P
T
MILLIMETERS
_0 2
4 85 +
_0 2
3 94 +
_0 3
6 02 +
_0 1
0 4+
0 15+0 1/-0 05
_0 2
1 63 +
_0 2
0 65 +
1 27
0 20+0 1/-0 05
SOP-8
Pin Assignment
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FA386P/F
Maximum Ratings*
Symbol
Parameter
Value
Unit
15
V
VCC
Supply Voltage
VIN
Input Voltage
±0.4
V
PD
Power Dissipation
1.25
W
Tstg
Storage Temperature
-65 to +150
°C
TJ
Junction Temperature
+150
°C
TL
Lead Temperature
+300
°C
*
Maximum ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the recommended operating conditions.
Recommended Operating Conditions
Symbol
Parameter
VCC
Supply Voltage
TA
Operating Temperature, All Package Types
Min
Max
Unit
4.0
12
V
0
+70
°C
This device contains protection circuitry to guard against damage due to high static voltages or electric
fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated voltages
to this high-impedance circuit. For proper operation,
VIN and VOUT should be constrained to the range GND ≤ (VIN or VOUT ) ≤ VCC.
Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or VCC).
Unused outputs must be left open.
Electrical Characteristics (Ta=25℃)
Symbol
Test Conditions
Parameter
V+
Operating Supply
Voltage
I+
Quiescent Current
Guaranteed Limits
Min
Typ
4
V+ = 6 V, VIN = 0
+
PO
Output Power
V = 6V, RL =8Ω, THD=10%
V+= 9V, RL =8Ω, THD=10%
250
500
325
1000
AV
Voltage Gain
V+= 6V, f=1kHz
10µF from Pin 1 and 8
24
44
26
46
BW
Bandwidth
V+= 6V, Pins 1 and 8 Open
250
Total Harmonic
Distortion
V = 6V, RL =8Ω, POUT=125mW,
f=1kHz,
Pins 1 and 8 Open
PSRR
Power Supply Rejection
Ratio
V+= 6V, f=1kHz, CBYPASS=10µF,
Pins 1 and 8 Open
IB
2011.12. 19
Input Resistance
Input Bias Current
Revision No : 0
Unit
12
V
8
mA
mW
28
48
dB
KHz
+
THD
RIN
Max
1.0
45
30
+
V = 6V, Pins 2 and 3 Open
250
%
dB
130
KΩ
400
nA
2/5
FA386P/F
Electrical Characteristics (Ta= 0℃~70℃)
Symbol
Parameter
V+
Operating Supply
Voltage
I+
Quiescent Current
Test Conditions
Guaranteed Limits
Min
Typ
4
V+ = 6 V, VIN = 0
+
220
480
325
1000
V+= 6V, f=1kHz
10µF from Pin 1 and 8
22
42
26
46
Bandwidth
V+= 6V, Pins 1 and 8 Open
250
THD
Total Harmonic
Distortion
V+= 6V, RL =8Ω, POUT=125mW,
f=1kHz,
Pins 1 and 8 Open
PSRR
Power Supply Rejection
Ratio
V+= 6V, f=1kHz, CBYPASS=10µF,
Pins 1 and 8 Open
PO
Output Power
V = 6V, RL =8Ω, THD=10%
V+= 9V, RL =8Ω, THD=10%
AV
Voltage Gain
BW
RIN
IB
Input Resistance
Input Bias Current
Max
12
V
8
mA
mW
30
50
45
20
V = 6V, Pins 2 and 3 Open
dB
KHz
1.5
+
Unit
250
%
dB
150
KΩ
600
nA
Application Information
GAIN CONTROL
INPUT BIASING
To make the FA386 a more versatile amplifier, two pins
(1 and 8) are provided for gain control. With pins 1
and 8 open the 1.35 KΩ resistor sets the gain at
20 (26 dB). If a capacitor is put from pin 1 to 8,
bypassing the 1.35 KΩ resistor, the gain will go up to
200 (46 dB). If a resistor is placed in series with the
capacitor, the gain can be set to any value from 20 to
200. Gain control can also be done by capacitively
coupling a resistor (or FET) from pin 1 to ground.
Additional external components can be placed in
parallel with the internal feedback resistors to tailor
the gain and frequency response for individual
applications. For example, we can compensate poor
speaker bass response by frequency shaping the
feeback path. This is done with a series RC from pin 1
to 5 (paralleling the internal 15 KΩ resistor). For 6 dB
effective bass boots: R≅15 KΩ, the lowest value for
good stable operation is R=10 KΩ if pin 8 is open. If
pins 1 and 8 are bypassed then R as low as 2 KΩ can
be used. This restriction is because the amplifier is
only compensated for closed-loop gains greater the 9.
2011.12.19
Revision No : 0
The schematic shows that both inputs are biased to
ground with a 50 KΩ resistor. The base current of the
input transistors is about 250 nA, so the inputs are at
at out 12.5 mV when left open. If the dc source
resistance oriving the IL386 is higher than 250 KΩ it
will contribute very little additional offset (about
2.5 mV at the input, 50 mV at the output). If the dc
source resistance is less than 10 KΩ, then shorting the
unused input to ground will keep the offset low (about
2.5 mV at the input, 50 mV at the output). For dc
source resistances between these values we can
eliminate excess offset by putting a resistor from the
unesed input to ground, equal in value to the dc source
resistance. Of course all affset problems are eliminated
if the input is capacitively coupled.
When using the FA386 with higher gains (by pessing
the 1.35 KΩ resistor between pins 1 and 8) it is
necessary to bypass the unused input, preventing
degradation of gain and possible instabilities. This is
done with a 0.1 µF capacitor or a short to ground
depending on the dc source resistance on the driven
input.
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FA386P/F
Typical Performance Characteristics
Quiescent Supply Current
vs Supply Voltage
Power Supply Rejection Ratio
(Referred to the Output)
vs Frequency
Peak-to-Peak Output Voltage
Swing vs Supply Voltage
Voltage Gain vs Frequency
Distortion vs Frequency
Distortion vs Output Power
Device Dissipation vs Output
Power — 4Ω Load
Device Dissipation vs Output
Power — 8Ω Load
Device Dissipation vs Output
Power — 16Ω Load
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FA386P/F
Typical Applications
Amplifier with Gain=20
Minimum Parts
Amplifier with Gain=200
10uF
+
Vs
Vs
6
2
-
1
2
FA386
3
FA386
7
3
10k
10
4
Amplifier with Gain=50
+
10
4
Low Distortion Power Weinbridge Oscillator
390
2
Vs
1.2k
6
-
2
10uF
1
FA386
7
3
+
1
bypass
FA386
3
3V-15mA
0.05uF
4
+
+
5
0.01uF
7
10
50uF
8
ELDEMA
CF-S-2158
+
5
Vin
6
-
250uF
8
10k
0.05uF
bypass
10uF
Vs
+
5
Vin
0.05uF
+
250uF
8
+
5
7
10k
1
250uF
8
Vin
6
-
0.05uF
bypass
4
Vo
10
RL
47k
f=1kHz
0.01uF
4.7k
Amplifier with Bass Boost
Square Wave Oscillator
f=1kHz
30k
10k
Vs
2
-
Vs
0.33uF
6
2
1
FA386
Vin
10k
7
3
+
+
5
1
0.1uF
250uF
8
6
-
50uF
8
Vo
FA386
5
+
Vo
0.05uF
bypass
10
RL
3
4
1k
+
RL
4
10k
f=1kHz
2011.12. 19
Revision No : 0
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