HDMI2C2-14HD Datasheet, PDF (10/31 Pages) STMicroelectronics – ESD protection and signal booster for HDMI™ 1.4 sink interface

Application information
HDMI2C2-14HD
2.4
TMDS channels ESD protection
The TMDS (Transient Minimized Differential Signaling) channels are described by the HDMI
1.4 standard. A total of 4 unidirectional differential pairs are used to transmit the video data
to the sink device. There are 3 channels dedicated to the video data, and 1 channel
dedicated to the clock. The frequency of the TMDS clock is 1/10 of the video data frequency.
The HDMI2C2-14HD provides a simple PCB layout solution, directly compliant with HDMI
connector type A. It protects the application against the ESD according the IEC61000-4-2
level 4 standard (+/-8 kV contact). The high bandwidth of this ESD protection allows to
transmit HD video high speed data with no disturbance of the signal. The TDR is compliant
with the HDMI specification.
A capacitor can be optionally connected to the ESD_DISCH pin in order to enhance the
ESD protection performances.
Figure 8. TMDS lines ESD protection functional diagram
VDD_IC
HDMI
ASIC
DAT_D2+_IC
DAT_D2 -_IC
DAT_D1+_IC
DAT_D1- _IC
DAT_D0+_IC
DAT_D0 - _IC
DAT_CLK+_IC
DAT_CLK- _IC
5V_IN
HDMI
connector
DAT_D2+
DAT_D2 -
DAT_D1+
DAT_D1-
DAT_D0+
DAT_D0 -
DAT_CLK+
DAT_CLK-
1
3
2
4
5
6
7
8
9
11
10
13
12
15
14
17
16
19
18
ESD_DSICH
2.5
Application block diagrams
The Figure 9 shows a typical application block diagram proposal implementing all the
possible options. The TMDS channels are simply connected to the connector and to the
HDMI ASIC. The diagram shows that the CEC driver can be totally independent from the
HDMI ASIC. By this way, even if the +5 V power supply and/or if the HDMI ASIC is sleeping,
the CEC bus is still active in low power mode. The designer has then all the tools to optimize
the power consumption of the global application in stand-by mode, and has the possibility to
implement a smart wake-up through the CEC bus enhancing the final user experience.
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DocID024813 Rev1