HDMI2C1-14HD Datasheet, PDF (10/32 Pages) STMicroelectronics – HPD pull down and signal conditioning

Application information
HDMI2C1-14HD
Figure 9. Simplified view of the electrical parameters of the HPD block
Signal on HPD link
5V
V_{IH_HPD}
HPD_IC signal
V_{IL_HPD}
2.3.2
HEAC functional block description
The HEAC link is described in the HDMI^™ 1.4 and HDMI^™ 2.0 standards as the HDMI^™
Ethernet and audio return channel. It corresponds physically to one differential wired pair
made of the Utility line and the HPD line. Two signals are transmitted through this link.
The first signal corresponds to the HDMI^™ Ethernet channel (HEC). The signal is
transmitted in differential mode (bidirectional) through the HEAC link. It is specified by the
100Base-TX IEEE 802.3 standard (fast Ethernet 100Mbps over twisted pair). Therefore, the
HEC integrates an Ethernet link into the video cable, enabling IP-based applications over
the HDMI^™ cable.
The second signal corresponds to the Audio Return Channel (ARC). The signal is
transmitted either in common mode (unidirectional, from sink to source) through the HEAC
link. It is specified by the IEC 60958-1 standard. The ARC function integrates an upstream
audio capability, simplifying the cabling of the audiovisual equipment. It is no more
necessary to use a coaxial cable from TV to audio amplifier.
The HDMI2C1-14HD helps the designer to implement this high added value HEAC function
in the application, protecting the link against the ESD with no disturbance of the signal. It
provides 2 distinct outputs HEAC+ and HEAC- in order to ease as much as possible the
PCB layout.
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DocID023674 Rev 2