The eARC feature makes the audio device work seamlessly with TVs. The device selection and volume control are performed by the TV remote, as if no audio device is attached at all. eARC uses two pins within the HDMI cable, the same pins intended for the HDMI Ethernet Channel feature, to transmit the low-jitter, high-bandwidth audio, and also bi-directional communication signals, which discover and control the audio feature. This is a great improvement over the old TOSLINK and SPDIF audio outputs, which required a separate cable and connector, and lack the ability to communicate between the audio device and TV.
Designed in 4x4mm QFN package with a 0.4mm pin pitch, the devices support both HDMI 2.1 eARC and HDMI 1.4 legacy ARC modes with automatic ARC fallback.
Lattice Semiconductor - www.latticesemi.com