The AK5371 is stereo A/D converter with USB I/F. The AK5371 integrates USB serial interface engine, USB transceiver, audio class processing unit, endpoints, and high quality 2 channel AD converter into the chip. As the AK5371 incorporates PLL, it can support several sampling frequencies, 8kHz, 11.025kHz, 22.05kHz, 44.1kHz, and 48kHz with only one crystal. Moreover, the AK5371 integrates volume control, and mute function. Not only power consumption at normal operation is very low, but also the current at suspend mode is less than 1A. The AK5371 includes 20dB fixed gain pre-amplifier. In addition to this, as the AK5371 also incorporates IPGA which can amplify the microphone signal up to +24dB, total gain is 44dB maximum.