Diodes Announces New USB Type-C Ultra-Low THD Analog Audio Port Switch

June 17 2019, 01:35
Diodes Incorporated announced the PI3A6386 USB Type-C multimedia port switch, designed to enable manufacturers to continue supporting legacy data and analog peripherals through USB Type-C ports. As a result of the adoption of USB Type-C ports in mobile phones and tablets, manufacturers are removing other ports such as USB 2.0 and 3.5mm audio sockets. The PI3A6386 port switch enables legacy data and audio signals to be passed through the USB Type-C port, allowing consumers to continue using existing peripherals.

The performance of the PI3A6386 port switch ensures a high level of audio quality, without signal distortion or noise. It includes autonomous microphone and ground line switching, while its CMOS design delivers an ON resistance of just 1Ω for the audio switching transistor. Low crosstalk between data and audio channels was also a design priority for the PI3A6386, and it succeeds here with a crosstalk rejection of -85dB at 30kHz.

Other design features include a programmable soft-start and soft-stop time, which eliminates the pop and click that audio signals can experience when they are DC-coupled. This delivers an audio experience free from distortion. The PI3A6386 operates from a supply of between 1.7V and 5.5V, making it suitable for portable devices. It can also process signals of ±3V, which further improves the dynamic range and audio quality.

The PI3A6386 supports USB 2.0 High Speed and Full Speed signals and USB Type-C Audio Accessory Mode. The THD of -110dB is maintained from 20Hz to 20kHz with a signal of 2.0V RMS into a 32Ω load. Separate ground switches are also used for the audio and data signals, to further minimize crosstalk.

PI3A6386 includes a dual, single-pole double throw (SPDT) switch for high-speed USB signal and high quality audio signal. It can be used in USB Type-C D+/D- switching for USB signal in data mode and analog audio signal in audio accessory mode. The PI3A6386 can also detect the microphone signals in SBU1 and SBU2, and automatically route them to the correct inputs of the microphone amplifier. Separate switches for microphone negative input and audio signal ground can minimize the crosstalk & echo between audio output signals and microphone input signals. Sideband switches can be configured to route SBU1 and SBU2 for sideband usage. 

The PI3A6386 is available in the TQFN-24 package. Further information is available at www.diodes.com
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