unisonic technologies co., lm386 linear integrated circuit www.unisonic.com.tw 1 copyright ? 2010 unisonic technologies co., qw-r107-007.g low voltage audio power amplifier ? description the utc lm386 is a power amplifier, designed for use in low voltage consumer applications. the gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pin 1 and pin 8 will increase the gain to any value up from 20 to 200. the inputs are ground referenced while the output automatically biases to one-half the supply voltage. the quiescent power drain is only 24 milliwatts when operating from a 6 voltage supply, making the lm386 ideal for battery operation. ? features *battery operation *minimum external parts *wide supply voltage range: 4v~12v *low quiescent current drain:4ma *voltage gains:20~200 *ground referenced input *self-centering output quiescent voltage *low distortion:0.2%(av =20,vs=6v,r l =8 ? ,po=125mw,f=1khz) ? ordering information ordering number normal lead free halogen free package packing lm386-s08-r lm386l-s08-r lm 386g-s08-r sop-8 tape reel lm386-s08-t lm386l-s08-t lm386g-s08-t sop-8 tube lm386-p08-r lm386l-p08-r lm38 6g-p08-r tssop-8 tape reel lm386-p08-t lm386l-p08-t lm386g-p08-t tssop-8 tube lm386-d08-t LM386L-D08-T lm386g-d08-t dip-8 tube
lm386 linear integrated circuit unisonic technologies co., ltd 2 www.unisonic.com.tw qw-r107-007.g ? pin configuration
lm386 linear integrated circuit unisonic technologies co., ltd 3 www.unisonic.com.tw qw-r107-007.g ? block diagram 1 2 3 4 5 6 7 8 gain gain -input +input gnd v out vs bypass 15k 15k 150 1.35k 15k 50k 50k
lm386 linear integrated circuit unisonic technologies co., ltd 4 www.unisonic.com.tw qw-r107-007.g ? absolute maximum ratings parameter symbol ratings unit supply voltage v cc 15 v input voltage v in -0.4v ~ +0.4v v dip-8 1250 sop-8 600 power dissipation tssop-8 p d 600 mw operating temperature t opr 0 ~ +70 c junction temperature t j +125 c storage temperature t stg -40 ~ +150 c note:1. absolute maximum ratings are stress ratings only and functional device operation is not implied. the device could be damaged beyond absolute maximum ratings. 2. the device is guaranteed to meet performance specifications within 0 ~70 operating temperature range and assured by design from ?20 ~85 . ? electrical characteristics (ta=25 c, unless otherwise specified.) parameter symbol test conditions min typ max unit operating supply voltage vss 4 12 v quiescent current i q vss=6v, v in =0 4 8 ma vss=6v, r l =8 , thd=10% 250 325 output power p out vss=9v, r l =8 , thd=10% 500 700 mw voltage gain g v vss=6v, f=1khz 10 f from pin 1 to pin 8 26 46 db db bandwidth bw vss=6v , pin1 and pin 8 open 300 khz total harmonic distortion thd p out =125mw, vs=6v,f=1khz r l =8 pin1 and pin 8 open 0.2 % rejection ratio rr vss=6v, f=1khz, c bypass =10 f pin1and pin 8 open, referred to output 50 db input resistance r in 50 k input bias current i bias vss=6v pin2 and pin 3 open 250 na
lm386 linear integrated circuit unisonic technologies co., ltd 5 www.unisonic.com.tw qw-r107-007.g ? application notes gain control to make the lm386 a more versatile am plifier, two pins(1and 8) are provi ded for gain control. with pins 1 and 8 open the 1.35 k resistor sets the gain at 20( 26db),if a capacitor is put from pin 1 to 8,bypassing the 1.35 k resistor, the gain will go up to 200(46db).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 capacit ively 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 exam ple we can compensate poor speaker bass response by frequency shaping the feedback path. this is done with a series rc from pin 1 to 5 (paralleling the internal 15 k resistor). for 6 db effective bass boost: r=15 k , the lowest value for good stable operation is r=10 k , if pin 8 is open, if pins 1 and 8 are bypassed then r as low as 2 k can be used. this restrictio n is because the amplifier is only compensated for closed-loop gains greater than 9. input biasing the schematic shows that both input s are biased to ground with a 50 k resistor. the base current of the input transistors is about 250na, so the input s are at about 12.5mw when left open. if t he dc source resistance driving the lm386 is higher than 250 k it will contribute very little additional offset (about 2.5mw at the input, 50mw at the output).if the dc source resistance is less than 10 k ,then shorting the unused input to ground will keep the offset low (about 2.5mv at the input,50 mv at the output).for dc source resi stances between these values we can eliminate excess offset by putting a resistor from the unus ed input to ground, equal in value to the dc source resistance. of course all offset problems are elim inated if the input is capacitively coupled. when using the lm386 with higher gains (bypassing the 1.35 k resistor between pins 1 and 8)it is necessary to bypass the unused input, preventing degradation of gain and possible instabi lities. this is done with a 0.1 f capacitor or a short to ground depending on t he dc source resistance on the driven input.
lm386 linear integrated circuit unisonic technologies co., ltd 6 www.unisonic.com.tw qw-r107-007.g ? typical applications circuit + - vs from detector 1 2 3 4 5 6 7 8 10k 250 f + 0.05 f am radio power amplifier + 10 f 10 f + cc v ol 10k r1 c1 2200pf 0.05 f + 8 ? speaker ferrite bead note 1: twist supply lead and supply ground very tightly. note 2: twist speaker lead and ground very tightly. note 3: ferrite bead in ferroxcube k5-001-001/3b with 3 turns of wire. note 4: r1c1 band limits input signals. note 5: all components must be spaced very closely to ic. 47
lm386 linear integrated circuit unisonic technologies co., ltd 7 www.unisonic.com.tw qw-r107-007.g ? typical characteristics 10 100 1k 10k 100k 20 0 frequency (hz) power supply rejection ratio(referred to the output) vs frequency power supply rejection (db) 10 v s =6v av=26db 4567 89101112 1 2 3 4 5 6 quiescent supply current vs supply voltage supply voltage(volts) supply current (ma) 30 40 50 60 no bypasscapacitor 0.5 f 1 f 10 f c 7 =50 f 4567 89101112 0 2 4 6 8 10 peak-to -peak output voltage swing vs supply voltage supply voltage(volts) output voltage (volts peak-to-peak) 8 4 16 r l = 20 50 100 200 500 1k 2k 5k 10k 17 18 19 20 21 22 frequency response with bass boost voltage gain (db) frequency (hz) 20k 23 24 25 26 27 voltage gain (db) total harmonic distortion (%)
lm386 linear integrated circuit unisonic technologies co., ltd 8 www.unisonic.com.tw qw-r107-007.g ? typical characteristics(cont.) 0 0.1 0.001 0.01 1.0 power output (watts) 1 2 3 4 5 6 7 8 9 10 vs=6v r l =8 f=1khz total harmonic distortion (%) distortion vs output power 0 0.1 0.2 0.3 0.4 0 0.2 0.4 0.6 0.8 1.0 device dissipaton vs output power - 4 load device dissipation (w) output power (w) 0.5 1.2 1.4 1.6 1.8 2.0 vs=6v vs=12v vs=9v 3% thd level 10% thd level 0 0.1 0.2 0.3 0.4 0 0.2 0.4 0.6 0.8 1.0 device dissipaton vs output power - 8 load device dissipation (w) output power (w) 0.5 1.2 1.4 1.6 1.8 2.0 0.6 0.7 0.8 0.9 1.0 vs=12v vs=9v vs=6v vs=16v 3% thd level 10% thd level 0 0.2 0.4 0.6 0.8 0 0.2 0.4 0.6 0.8 1.0 device dissipaton vs output power -16 load device dissipation (w) output power (w) 1.0 1.21.4 1.61.8 2.0 vs=12v vs=9v vs=6v vs=16v 3% thd level 10% thd level utc assumes no respon sibility for equipment failures that result fr om using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior writ ten consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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