Low Voltage Audio Power Amplifier
General Description
is a power amplifier designed for u in low volt-age consumer applications.The gain is internally t to 20to keep external part count low,but the addition of an external resistor and capacitor between pins 1and 8will increa the gain to any value from 20to 200.
The inputs are ground referenced while the output automati-cally bias to one-half the supply voltage.The quiescent power drain is only
24milliwatts when operating from a 6volt supply,making the Features
n Battery operation
n Minimum external parts
n Wide
科技创新竞赛
supply voltage range:4V–12V n Low quiescent current drain:4mA n Voltage gains from 20to 200n Ground referenced input
n Self-centering output quiescent voltage
n
Low distortion:0.2%(A V =20,V S =6V,R L =8Ω,P O =125mW,f =1kHz)
n Available in 8pin SOP package Applications
n AM-FM radio amplifiers
n Portable tape player amplifiers n Intercoms
n TV sound systems n Line drivers
n Ultrasonic drivers n Small rvo drivers n
Power converters
腰缠十万Equivalent Schematic and Connection Diagrams
Small Outline,
Wing Shing Computer Components Co., (H.K.)Ltd.Tel:(852)2341 9276 Fax:(852)2797 8153Homepage: E-mail:
Low Voltage Audio Power Amplifier
WS386M-1 ideal for battery operation
Pin Connection
and DIP package
Ordering Information
8-1
LM386-1
The LM386-1
Note 1:All voltages are measured with respect to the ground pin,unless otherwi specified.
Note 2:Absolute Maximum Ratings 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-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 25˚C,the device must be derated bad on a 150˚C maximum junction temperature and a thermal resistance of 170˚C/W for the small outline package.
Absolute Maximum Ratings
Dual-In-Line Package Soldering (10c)+260˚C
Small Outline Package (SOIC )
Vapor Pha (60c)+215˚C Infrared (15c)
+220˚C
Soldering Information
操作系统的作用是
Supply Voltage (WS386-1)
Package Dissipation(Note3)
(WS386N) 1.25W 0.73W
(WS386M)
.4V
+-65 C to +150 C
0 C to+70 C +150 C
Input Voltage
Storage Temperature
Junction Temperature
Operating Temperature -8-2
Application Hints
GAIN CONTROL
a more versatile amplifier,two pins (1
and 8)are provided for gain control.With pins 1and 8open the 1.35k Ωresistor ts the gain at 20(26dB).If a capacitor is put from pin 1to 8,bypassing the 1.35k Ωresistor,the gain will go up to 200(46dB).If a resistor is placed in ries with the capacitor,the gain can be t to any value from 20to 200.Gain control can also be done by capacitively cou-pling a resistor (or FET)from pin 1to ground.
Additional external components can be placed in parallel with the internal feedback resistors to tailor the gain and fre-quency respon for individual applications.For example,we can compensate poor speaker bass respon by fre-quency shaping the feedback path.This is done with a ries RC from pin 1to 5(paralleling the internal 15k Ωresistor).For 6dB effective bass boost:R .15k Ω,the lowest value for good stable operation is R =10k Ωif pin 8is open.If pins 1and 8are bypasd then R as low as 2k Ωcan be ud.This restriction is becau the amplifier is only compensated for clod-loop gains greater than 9.
INPUT BIASING
The schematic shows that both inputs are biad to ground with a 50k Ωresistor.The ba current of the input transis-tors is about 250nA,so the inputs are at about 12.5mV when left open.If the dc source resistance driving the LM386is higher than 250k Ωit will contribute very little additional offt (about 2.5mV at the input,50mV at the output).If the dc source resistance is less than 10k Ω,then shorting the unud input to ground will keep the offt low (about 2.5mV at the input,50mV at the output).For dc source resistances between the values we can eliminate excess offt by put-ting a resistor from the unud input to ground,equal in value to the dc source resistance.Of cour all offt prob-lems are eliminated if the input is capacitively coupled.with higher gains (bypassing the 1.35k Ωresistor between pins 1and 8)it is necessary to by-pass the unud input,preventing degradation of gain and possible instabilities.This is done with a 0.1µF capacitor or a short to ground depending on the dc source resistance on the driven input.歌曲一生无悔
紫癜如何治疗
1405
Gain -input +input GND GND VOUT V CC 100BYPASS Gain
390101514051405120
78
1201201205506006007504404A 4B 5623Coordinates Pad N Pad Name X Y 975665100Pad Location Coordinates
18-3
LM386-1
To make LM386-1When using LM386-1
Typical Performance Characteristics
Quiescent Supply Current vs Supply
Voltage
Power Supply Rejection Ratio (Referred to the Output)vs
楠莉
Frequency
Peak-to-Peak Output Voltage Swing vs Supply
Voltage
Voltage Gain vs
Frequency
Distortion vs
Frequency
Distortion vs Output
Power天的单位
Device Dissipation vs Output Power —4Ω
Load
Device Dissipation vs Output Power —8Ω
Load Device Dissipation vs Output Power —16Ω
Load
8-4
LM386-1
Typical Applications
Amplifier with Gain =20新闻专业大学排名
Minimum
Parts
Amplifier with Gain =
200
Amplifier with Gain =
50
Low Distortion Power Wienbridge
Oscillator
Amplifier with Bass
Boost
Square Wave
Oscillator
8-5
LM386-1
