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Quad
Terminated
TMDSRx
withEQ
Quad
Terminated
TMDSRx
withEQ
Quad
Terminated
TMDSRx
withEQ
Quad
TMDS Tx
Quad
Terminated
TMDSRx
withEQ
Quad
TMDS Tx
MUX
SCL1
SDA1
SCL3
SDA3
SCL_SINK1
SDA_SINK1
5V_PWR1
5V_PWR3
5V_SINK1
HPD_SINK1
ControlLogic
GPIO0(SA1) GPIO1(SB1) GPIO5(SA2) GPIO6(SB2)
HIGH=source1
LOW=source2
TMDSDATA 5
TMDSDATA 4
TMDSDATA 3
TMDSDATA 2
TMDSDATA 1
TMDSDATA 0
TMDSCLOCK
TMDSDATA 5
TMDSDATA 4
TMDSDATA 3
TMDSDATA 2
TMDSDATA 1
TMDSDATA 0
TMDSCLOCK
TMDSDATA 5
TMDSDATA 4
TMDSDATA 3
TMDSDATA 2
TMDSDATA 1
TMDSDATA 0
TMDSCLOCK
UnusedOutput
SCL_SINK2
SDA_SINK2
HPD_SINK2
5V_SINK2
SCL2
SDA2
SCL4
SDA4
HPD2
HPD4
5V_PWR2
5V_PWR4
HPD1
HPD3
UnusedInput
UnusedInput
Tosource1
Tosource2
Fromsource2
Fromsource1
From/Tosource
2
From/Tosource
1
FromSINK
ToSINK
From/ToSINK
Fromsource1
Fromsource2
ToSINK
Layout Considerations
I
2
C Function Description
TMDS442
SLLS757A – AUGUST 2006 – REVISED MARCH 2007
Figure 32. Dual-Link 2-to-1 DVI/HDMI Switch Configuration
In a dual link application, the unused TMDS input should be configured as follows: the complementary input pin
is grounded through a 1-k Ω resistor, and the other pin left open.
The high-speed TMDS inputs are the most critical paths for the TMDS442. There are several considerations to
minimize discontinuities on these transmission lines between the connectors and the device:
• The TMDS differential inputs should be layout in the shortest stubs from connectors directly
• Maintain 100- Ω differential impedance into and out of the TMDS442
• Keep an uninterrupted ground plane beneath the high-speed I/Os
• Keep the ground-path vias to the device as close as possible to allow the shortest return current path
The SCL/SDA and SCL_SINK/SDA_SINK pins are 5-V tolerant when the device is powered off and high
impedance under low supply voltage, 1.5 V or below. If the device is powered up and the I
2
C circuits are
enabled, and EN = high, the driver T (see Figure 33 ) is turned on or off depending up on the corresponding R
side voltage level.
When the R side is pulled low below 1.5 V, the corresponding T side driver turns on and pulls the T side down to
a low level output voltage, V
OL
. The value of V
OL
depends on the input to the OVS pin. When OVS is left floating
32 Submit Documentation Feedback Copyright © 2006 – 2007, Texas Instruments Incorporated
Product Folder Link(s): TMDS442