LM 380 The LM 380 is a power audio amplifier for consumer applications. The internal gain is fixed at 34dB. The output automatically self-centers to one-half the supply voltage. The output is short-circuit proof with internal thermal limiting. The package outline is standard dual-in-line. The LM 380N uses the center three pins on either side to act as a heatsink. This means the copper on the PC board must be large enough to dissipate the heat. Features Wide supply voltage range: 10v-22v Power @ 8ohms 1%THD 4-watt Voltage gain fixed at 50 High peak current capability: 1.3A Input referenced to GND High input impedance: 150k Low distortion Quiescent output voltage is ½ the supply voltage Standard dual-in-line package Quiescent current 7mA typical Low quiescent power drain: 0.13W (VS= 18V) The LM 380 naturally produces half-rail voltage on pin 8 during quiescent conditions and this feature will produce a half-rail voltage for op-amps etc. In the circuit below, if the input voltage is 20v, the output voltage will be +10v and -10v.