STDVE003A_08 Datasheet, PDF (13/41 Pages) STMicroelectronics – Adaptive 3.4 Gbps 3:1 TMDS/HDMI signal equalizer

STDVE003A
Functional description
3.2.1
SEL operating modes
The active source is selected by configuring source select inputs, S1, S2 and S3. The
selected TMDS inputs from each port are switched through a 3-to-1 multiplexer. The I²C
interface of the selected input port is linked to the I²C interface of the output port, and the
hot plug detector (HPD) of the selected input port is output to HPD_SINK. For the unused
ports, the I²C interfaces are isolated, and the HPD pins are kept low.
Table 5. SEL operating modes
Control pins
I/O selected
Hot-plug detect status
SCL_SINK
S1
S2
S3
Y/Z
HPD1
HPD2
HPD3
SDA_SINK
SCL1
H
X
X
A1/B1
HPD_SINK
L
L
SDA1
SCL2
L
H
X
A2/B2
SDA2
L
HPD_SINK
L
SCL3
L
L
H
A3/B3
L
SDA3
L
HPD_SINK
L
L
L
None
(Z)
None (Z)
L
L
L
H: logic high; L: logic low; X: don't care; Z: high impedance
3.3
HPD pins
The input pin HPD_SINK is 5 V tolerant, allowing direct connection to 5 V signals. The
switch is able to pass both 0 V and 5 V signal levels. The HPD_SINK is an input pin while
the A_HPD, B_HPD and C_HPD are open-drain outputs.
3.4
DDC channels
The DDC channels are designed with a bidirectional NMOS gate, providing 5 V signal
tolerance. The 5 V tolerance allows direct connection to a standard I²C bus, thus eliminating
the need for a level shifter. There should be external pull-up resistors on either side of the
device on both the SCL and SDA lines.
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