Silicore Low Voltage Audio Power Amplifier DESCRIPTION D386 Outline Drawing The D386 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 pins 1 and 8 will increase the gain to any value 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 volt supply, making the LM386 ideal for battery operation. FEATURE Battery operation Minimu m ex tern al parts Wide supply voltage range: 4V–12V Low quiescent current drain: 4mA Voltage gains from 20 to 200 Available in 8 pin DIP package PIN CONFIGURATION APPLICATION AM-FM rad io amp lifiers Portable tape player amplifiers Intercoms TV sound systems Line drivers Ultrasonic drivers Small servo drivers Power converters SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 1/6 Silicore D386 EQUIVALENT SCHEMATIC AND CONNECTION DIAGRAMS ABSOLUTE MAXIMUM RATINGS (Ta=25 °C) Characteristic Maximum Input Vo ltage Supply Vo ltage Maximum Power Disspation Soldering temp erature(10 sec.) Junction Temperature Operating Temperature Storage Temp erature Symbol VIN Vcc PD TS Tj Tamb Tstg Value ±0.4 15 660 260 150 -10~+70 -40~125 Unit V V mV °C °C °C °C ELECTRICAL CHARACTERISTICS (Unless otherwise specified: Vcc=6V , R L =8Ω , f=1kHz , Tamb=25℃ ) Characteristics Operating Supply Voltage Quiescent Current Output Power Voltage Gain Bandwidth Total Harmonic Distortion Power Supply Rejection Ratio Test conditions Min Typ Vcc Vcc=6V， V I N =0 Vcc=6V, R L =8Ω， THD=10% Vcc=9V, R L =8Ω， THD=10% Vcc=6V, f=1kHz 1 脚 、 8 脚 间 接 1 0μ F 电 容 Vcc=6V， 脚 1 、 8 开 路 Vcc=6V， R L =8Ω ， Po=125mW ， f=1kHz 脚 1、 8 开 路 Vcc=6V， f=1kHz， C B Y PA S S =1 0μ F， 1、 8 脚 开 路 、 输 出 为 参 考 Input Resistance Input Bias Current Symbol Vcc=6V， 2 、 3 脚 开 路 Icc Unit 12 V mA 4 325 700 26 46 300 8 BW 2 50 5 00 - - kHz THD - 0.2 - % Po Av PSRR RIN IB SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC Max mW 50 - 50 250 dB dB - kΩ nA 2/6 Silicore D386 APPLICATION HINTS GAIN CONTROL To make the D386 a mo re versatile amplifier, two pins (1and 8) are provided for gain control. With pins 1 and 8 open the 1.35 kW resistor sets the gain at 20 (26 dB). If a capacitoris put from pin 1 to 8, bypassing the 1.35 kW 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 feedback path. This is done with a series RC from pin 1 to 5 (paralleling the internal 15 kW resistor). For 6 dB effective bass boost: R . 15 kW, the lowest value for good stable operation is R = 10 kW if pin 8 is open. If pins 1 and 8 are bypassed then R as low as 2 kW can be used. This restriction is because the amplifier is only compensated for closed-loop gains greater than 9. INPUT BIASING The schematic shows that both inputs are biased to ground with a 50 kW resistor. The base current of the input transistors is about 250 nA, so the inputs are at about 12.5 mV when left open. If the dc source resistance driving the D386 is higher than 250 kW 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 kW, 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 unused input to ground, equal in value to the dc source resistance. Of course all offset problems are eliminated if the input is capacitively coupled. When using the D386 with higher gains (byp assing the 1.35 kW 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. SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 3/6 Silicore D386 APPLICATION CIRCUIT Vs 6 - 2 Vin 8 5 250uF Fig1 10uF 8 250uF 5 D386 + 7 0.05uF 3 2 Vin D386 10K 6 Vs 1 - 1 10 4 + 10K Amplifier with Gain = 20 3 4 Fig2 7 0.05uF 旁路 10 Amplifier with Gain = 200 (Minimu m Parts) 1.2K 6 4 Fig3 250uF 5 7 0.05uF + 390 8 5 D386 D386 3 10uF 1 - 8 Vin 10K 2 10uF 1 - 2 Vs 6 Vs 旁路 220 热敏电阻 3 7 0.05uF + 4 10 ÅÔ· 10 4.7K Amplifier with Gain = 50 Fig4 250uF Vo RL 0.01uF Low Distortion Power Wienbridge Oscillator Vs 6 - 0.1uF D386 3 1 + 4 8 250uF 5 10 0.05uF Vin 10K 旁路 7 0.033uF 2 2 6 Vs - 1 30K 8 D386 Vo 3 + 50uF Vo 5 7 RL 4 RL 10K 1K 10K Fig5 Amplifier with Bass Boost Fig6 Square Wave Oscillator SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 4/6 Silicore Cc Vin VoL 10K D386 Vs 0.05uF 6 10K 2 1 - 10uF 8 2200pF D386 3 + 4 Fig 7 铁氧体线圈 250uF 5 7 10uF 47 0.05uF 8 喇叭 AM Rad io Po wer Amplifier TYPICAL PERFORMANCE CHARACTERISTICS SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 5/6 Silicore D386 SHAOXING SILICORE TECHNOLOGY CO.,LTD www. Silicore. com. cn CHMC 6/6