EP91H0 is Explore Microelectronic HDMI ARC IC that handle the Audio Return Channel functions. This chip transmit and receive the IEC 60958-1 audio stream and compliant with HDMI 1.4 specification. Package size is a 14-pin SOP IC and standard pack is 2Kpcs in tape & reel.


With the ARC feature, new TV can use just a single HDMI cable to send audio data upstream to A/V receiver or surround audio amplifier and remove the need for a separate S/PDIF audio connection. The Sony/Philips Digital Interface Format (S/PDIF) allows digital audio interconnect used in consumer audio equipment to output audio over a short distances. The transmission usually is done over a fibre optic cable with TOSLINK connector. S/PDIF carry 2 channel of uncompressed PCM audio or compressed 5.1/7.1 surround sound and is standardised in IEC 60958.

HDMI with Audio Return Channel ARC

Conventional TV connection to audio speaker uses Optical-Out connection from the TV, connecting to the external audio speakers at the Optical-In connector. To use the ARC feature, you must connect the HDMI cable to the TV HDMI socket marked with ARC compatible sign. On the audio speaker, you need to look for HDMI socket marked with ARC compatible connection.

ARC (Audio Return Channel) is a feature of HDMI spec V1.4 initiated in 2009, allowing the audio signal at the TV’s HDMI interface sending back to the audio system’s HDMI interface. With this ARC connection, you can listen to the TV’s internal audio sources like Smart TV apps and tuned over-the-air channels at your audio system. Using the aspects of CEC (consumer electronics control), you can adjust the volume of your audio system like the SoundBar with the TV remote control.