HDMI2C2-14HD Datasheet, PDF (9/31 Pages) STMicroelectronics – ESD protection and signal booster for HDMI™ 1.4 sink interface

HDMI2C2-14HD
Application information
2.3
HEAC link and HPD line protection
The HDMI2C2-14HD proposes a unique solution in order to manage and protect both the
HEAC and the HPD links.
The HPD line is describe in the HDMI standards as a Hot Plug Defect function.This line is
used by the source device in order to detect if a sink device is connected through an HDMI
cable.
The HEAC link is described in the HDMI 1.4 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 in common mode (unidirectional, from sink to source) through the HEAC link. It
is specified by the IEC 60958-1 standard. The ARC integrates an upstream audio capability,
simplifying the cabling of the audiovisual equipments. 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,
thanks to the integrated matching circuitry on HEAC+ line. It provides 2 distinct outputs
HEAC+ and HEAC- in order to ease as much as possible the PCB layout.
Both HPD and utility inputs (cable side) integrate a protection against ESD which is
compliant with IEC61000-4-2 standard, level 4 (8kV contact).
Figure 7. HEAC / HPD / utility functional block diagram
VDD_IC
HPD
HDMI
ASIC
or
HEAC-
IC
HEAC+
HEAC- / HPD_IC
HEAC+
HDMI2C2-14HD
HDMI
connector
HPD _{HPD / HEAC}-
1
2
3
4
5
6
7
8
9
10
11
12
13
Utility
14
15
16
Utility / HEAC+
17
18
19
DocID024813 Rev1
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