Sd7402 sd7402 = hd0802a

SD7402 is a 3-channel audio amplifier with built-in microphone input amplifier. High quality audio output is available through simpleperipheral circuit and the amplifier gain can be adjusted flexibly by external resistor. Its audio output signal-noise ratio is 85dB, total harmonic distortion is 0.05% and the channel separation is 78dB.
Based on BICMOS technology, SD7402 can stably work in +5V/-12V system with built-in voltage regulator. The built-in filter can improve the audio quality by attenuating the other signals. The mute and ON/OFF POP suppression functions can suppress the POP noise in the input signal.
It is widely used as pre-amplification in various stereo and 2.1-channel audio systems to pre-amplify the signal from the main chip audio.