lm386 低压音频小功率放大器_W

1、 1999 National Semiconductor CorporationDS006976LM386 Low Voltage Audio Power AmplifierSeptember 1997LM386Low Voltage Audio Power AmplifierGeneral DescriptionFeaturesThe LM386 is a power amplifier designed for use in low volt-n Battery operationage consumer applications. The gain is

2、internally set to 20 ton Minimum external partskeep external part count low, but the addition of an externaln Wide supply voltage range: 4V12V or 5V18V resistor and capacitor between pins 1 and 8 will increase then Low quiescent current drain: 4 mAgain to any value up to 200.n Voltage gains from 20

3、to 200The inputs are ground referenced while the output is auto-n Ground referenced inputmatically biased to one half the supply voltage. The quies-n Self-centering output quiescent voltage cent power drain is only 24 milliwatts when operating from an Low distortion6 volt supply, making the LM386 id

4、eal for battery operation.n Available in 8 pin MSOP packageApplicationsn AM-FM radio amplifiersn Portable tape player amplifiersn Intercomsn TV sound systemsn Line driversn Ultrasonic drivers n Small servo drivers n Power convertersEquivalent Schematic and Connection DiagramsSmall Outline, Molded Mi

5、ni Small Outline, and Dual-In-Line PackagesDS006976-2Top ViewOrder Number LM386M-1,DS006976-1LM386MM-1, LM386N-1, LM386N-3 or LM386N-4See NS Package Number M08A, MUA08A or N08E2Absolute Maximum Ratings (Note 2)Dual-In-Line PackageIf Military/Aerospace specified devices are required,S

6、oldering (10 sec)+260Cplease contact the National Semiconductor Sales Office/Small Outline PackageDistributors for availability and specifications.(SOIC and MSOP)Supply VoltageVapor Phase (60 sec)+215C(LM386N-1, -3, LM386M-1)15VInfrared (15 sec)+220CSupply Voltage (LM386N-4)22VSee AN-450 “Surface Mo

7、unting Methods and Their Effect Package Dissipation (Note 3)on Product Reliability” for other methods of solderingsurface mount devices.(LM386N)1.25WThermal Resistance(LM386M)0.73WqJC (DIP)37C/W(LM386MM-1)0.595WqJA (DIP)107C/WInput Voltage0.4VqJC (SO Package)35C/WStorage Temperature65C to +150CqJA (

8、SO Package)172C/WOperating Temperature0C to +70CqJA (MSOP)210C/WJunction Temperature+150CqJC (MSOP)56C/W Soldering InformationElectrical Characteristics (Notes 1, 2) TA = 25CNote 1: All voltages are measured with respect to the ground pin, unless otherwise specified.Note 2: Absolute Maximum Ratings

9、indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func- tional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar-

10、 antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance.Note 3: For operation in ambient temperatures above 25C, t

11、he device must be derated based on a 150C maximum junction temperature and 1) a thermal resis- tance of 80C/W junction to ambient for the dual-in-line package and 2) a thermal resistance of 170C/W for the small outline package.ParameterConditionsMinTypMaxUnitsOperating Supply Voltage (VS)LM386N-1, -

12、3, LM386M-1, LM386MM-1 LM386N-4451218V VQuiescent Current (IQ)VS = 6V, VIN = 048mAOutput Power (POUT)LM386N-1, LM386M-1, LM386MM-1 LM386N-3LM386N-4VS = 6V, RL = 8W, THD = 10% VS = 9V, RL = 8W, THD = 10% VS = 16V, RL = 32W, THD = 10%2505007003257001000mW mW mWVoltage Gain (AV)VS = 6V, f = 1 kHz10 F f

13、rom Pin 1 to 82646dB dBBandwidth (BW)VS = 6V, Pins 1 and 8 Open300kHzTotal Harmonic Distortion (THD)VS = 6V, RL = 8W, POUT = 125 mWf = 1 kHz, Pins 1 and 8 Open0.2%Power Supply Rejection Ratio (PSRR)VS = 6V, f = 1 kHz, CBYPASS = 10 FPins 1 and 8 Open, Referred to Output50dBInput Resistance (RIN) Inpu

14、t Bias Current (IBIAS)VS = 6V, Pins 2 and 3 Open50250kW nA3Application HintsGAIN CONTROLINPUT BIASINGTo make the LM386 a more versatile amplifier, two pins (1The schematic shows that both inputs are biased to ground and 8) are provided for gain control. With pins 1 and 8 openwith a 5

15、0 kW resistor. The base current of the input transis- the 1.35 kW resistor sets the gain at 20 (26 dB). If a capacitortors is about 250 nA, so the inputs are at about 12.5 mV is put from pin 1 to 8, bypassing the 1.35 kW resistor, thewhen left open. If the dc source resistance driving the LM386 gain

16、 will go up to 200 (46 dB). If a resistor is placed in seriesis higher than 250 kW it will contribute very little additional with the capacitor, the gain can be set to any value from 20offset (about 2.5 mV at the input, 50 mV at the output). If the to 200. Gain control can also be done by capacitive

17、ly cou-dc source resistance is less than 10 kW, 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 Additional external components can be placed in parallelat the input, 50 mV at the output). For dc source resistanceswith the

18、 internal feedback resistors to tailor the gain and fre-between these values we can eliminate excess offset by put- quency response for individual applications. For example,ting a resistor from the unused input to ground, equal in we can compensate poor speaker bass response by fre-value to the dc s

19、ource resistance. Of course all offset prob- quency shaping the feedback path. This is done with a serieslems are eliminated if the input is capacitively coupled.RC from pin 1 to 5 (paralleling the internal 15 kW resistor).When using the LM386 with higher gains (bypassing the For 6 dB effective bass

20、 boost: R 15 kW, the lowest value1.35 kW resistor between pins 1 and 8) it is necessary to by- for good stable operation is R = 10 kW if pin 8 is open. If pinspass the unused input, preventing degradation of gain and1 and 8 are bypassed then R as low as 2 kW can be used.possible instabilities. This

21、is done with a 0.1 F capacitor or This restriction is because the amplifier is only compensateda short to ground depending on the dc source resistance on for closed-loop gains greater than 9.the driven 4Typical Performance CharacteristicsQuiescent Supply CurrentPower Supply Rej

22、ection RatioPeak-to-Peak Output Voltage vs Supply Voltage(Referred to the Output)Swing vs Supply Voltagevs FrequencyDS006976-5DS006976-13DS006976-12Voltage Gain vs FrequencyDistortion vs FrequencyDistortion vs Output PowerDS006976-14DS006976-15DS006976-16Device Dissipation vs OutputDevice Dissipatio

23、n vs OutputDevice Dissipation vs Output Power 4W LoadPower 8W LoadPower 16W LoadDS006976-17DS006976-18DS006976-195Typical ApplicationsAmplifier with Gain = 20Amplifier with Gain = 200 Minimum PartsDS006976-4DS006976-3Amplifier with Gain = 50Low Distortion Power Wienbridge OscillatorD

24、S006976-6DS006976-7Amplifier with Bass BoostSquare Wave OscillatorDS006976-8DS006976-96Typical Applications (Continued)Frequency Response with Bass BoostDS006976-10AM Radio Power AmplifierDS006976-11Note 4: Twist Supply lead and supply ground very tightly.Note 5: Twist speaker lead a

25、nd 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.7Physical Dimensions inches (millimeters) unless otherwise notedSO Package (M) Order Number LM3

26、86M-1 NS Package Number M08A8Physical Dimensions inches (millimeters) unless otherwise noted (Continued)8-Lead (0.118” Wide) Molded Mini Small Outline Package Order Number LM386MM-1NS Package Number MUA08ANational does not assume any responsibility for use of any circuitry described,

27、 no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.LM386 Low Voltage Audio Power AmplifierPhysical Dimensions inches (millimeters) unless otherwise noted (Continued)Dual-In-Line Package (N)Order Number LM386N

28、-1, LM386N-3 or LM386N-4NS Package Number N08ELIFE SUPPORT POLICYNATIONALS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:1. Life support devices or systems are devices or2. A critical component is any component of a life systems which, (a) are intended for