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to 200. Gain control can also be done by capacitively cou- dc source resistance is less than 10 k&!, then shorting the
pling a resistor (or FET) from pin 1 to ground. 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
Additional external components can be placed in parallel
between these values we can eliminate excess offset by put-
with the internal feedback resistors to tailor the gain and fre-
ting a resistor from the unused input to ground, equal in
quency response for individual applications. For example,
value to the dc source resistance. Of course all offset prob-
we can compensate poor speaker bass response by fre-
lems are eliminated if the input is capacitively coupled.
quency shaping the feedback path. This is done with a series
RC from pin 1 to 5 (paralleling the internal 15 k&! resistor). When using the LM386 with higher gains (bypassing the
For 6 dB effective bass boost: R . 15 k&!, the lowest value 1.35 k&! resistor between pins 1 and 8) it is necessary to by-
for good stable operation is R = 10 k&! if pin 8 is open. If pins pass the unused input, preventing degradation of gain and
1 and 8 are bypassed then R as low as 2 k&! can be used. possible instabilities. This is done with a 0.1 µF capacitor or
This restriction is because the amplifier is only compensated a short to ground depending on the dc source resistance on
for closed-loop gains greater than 9. the driven input.
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LM386
Typical Performance Characteristics
Quiescent Supply Current
Power Supply Rejection Ratio
Peak-to-Peak Output Voltage
vs Supply Voltage
(Referred to the Output)
Swing vs Supply Voltage
vs Frequency
DS006976-5
DS006976-13
DS006976-12
Voltage Gain vs Frequency Distortion vs Frequency Distortion vs Output Power
DS006976-15 DS006976-16
DS006976-14
Device Dissipation vs Output
Device Dissipation vs Output
Device Dissipation vs Output
Power  4&! Load
Power  8&! Load
Power  16&! Load
DS006976-17
DS006976-18
DS006976-19
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LM386
Typical Applications
Amplifier with Gain = 20
Amplifier with Gain = 200
Minimum Parts
DS006976-4
DS006976-3
Amplifier with Gain = 50 Low Distortion Power Wienbridge Oscillator
DS006976-6
DS006976-7
Amplifier with Bass Boost Square Wave Oscillator
DS006976-8
DS006976-9
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LM386
Typical Applications (Continued)
Frequency Response with Bass Boost
DS006976-10
AM Radio Power Amplifier
DS006976-11
Note 4: Twist Supply lead and supply ground very tightly.
Note 5: Twist speaker lead and ground very tightly.
Note 6: Ferrite bead in Ferroxcube K5-001-001/3B with 3 turns of wire.
Note 7: R1C1 band limits input signals.
Note 8: All components must be spaced very closely to IC.
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LM386
Physical Dimensions inches (millimeters) unless otherwise noted
SO Package (M)
Order Number LM386M-1
NS Package Number M08A
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LM386
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
8-Lead (0.118 Wide) Molded Mini Small Outline Package
Order Number LM386MM-1
NS Package Number MUA08A
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LM386
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Dual-In-Line Package (N)
Order Number LM386N-1, LM386N-3 or LM386N-4
NS Package Number N08E
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LM386 Low Voltage Audio Power Amplifier [ Pobierz całość w formacie PDF ]