TMDS171 Datasheet, PDF (42/62 Pages) Texas Instruments – 3.4 Gbps TMDS RETIMER

TMDS171, TMDS171I
SLLSEN7A – OCTOBER 2015 – REVISED DECEMBER 2015
9 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The TMDS171 was defined to work in many applications. This includes source applications like a Blu-Ray DVD
player or AVR. The adaptive receive equalizer makes it ideal for sink applications like HDTV, monitors and
projectors where cable length can be widely varied. The TMDS171 is also capable of working as an active cable
to extend the cable length even further.
9.1.1 Application Chain Showing DDC Connections
The DDC circuitry inside the TMDS171 allows multiple stage operation as shown in Figure 56. The retimer
devices can be connected to any of the bus segments. The number of devices that can be connected in series is
limited by repeater delay/time of flight considerations for the maximum bus speed requirements.
SOURCE
Active Cable
SINK
3.3V
5V
5V
5V
5V
3.3V
Rup Rup
RUPsouce
TSCL
TSDA
SLK_SRC SLK_SINK
SDA_SRC SDA_SINK
RUPsink
RUPsource
SLK_SRC SLK_SINK
SDA_SRC SDA_SINK
RUPsink
Rup Rup
SLK_SRC SLK_SINK
SDA_SRC SDA_SINK
RSLK
RSDA
BUS
MASTER
C1
C2
C3
C2
C2
C3
C2
TMDS171
TMDS171
TMDS171
C1
BUS
SLAVE
Figure 56. Typical Series Application
9.1.2 DDC Pull Up Resistors
This section is for information only and subject to change depending upon system implementation. The pull-up
resistor value is determined by two requirements.
1. The maximum sink current of the I²C buffer: The maximum sink current is 3 mA or slightly higher for an I²C
driver supporting standard-mode I²C operation.
Rup(min)
=
V_CC
I_{sin k}
(1)
2. The maximum transition time on the bus:
The maximum transition time, T, of an I²C bus is set by an RC time constant, where R is the pull-up resistor
value, and C is the total load capacitance. The parameter, k, can be calculated from Equation 2 by solving
for t, the times at which certain voltage thresholds are reached. Different input threshold combinations
introduce different values of t. Table 32 summarizes the possible values of k under different threshold
combinations.
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