HDMI2C1-14HD Datasheet, PDF (12/32 Pages) STMicroelectronics – HPD pull down and signal conditioning

Application information
2.5
Back drive protection
Figure 11. Back drive current diagram
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Thanks to the innovative switch architecture, back drive current is blocked whatever back
drive current is coming from +5V_OUT and/or DDC lines (see figure 11).
In case of no activity on CEC bus, or if the CEC driver is off (V_{DD_CEC} = 0), the output CEC
pin is put in high impedance mode (open circuit) protecting the circuitry and the application
against hazardous back drive.
2.6
TMDS channels ESD protection
The TMDS (Transient Minimized Differential Signaling) channels are described by the HDMI
2.0 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 HDMI2C1-14HD 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 data with no disturbance of the signal up to 5.94 Gbps per channel.
A capacitor can be optionally connected to the ESD_DISCH pin in order to enhance the
ESD protection performances.
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