VSADJ (k:)

4.5

5

5.5

6

6.5

7

7.5

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

D001

IN_D2P/N

IN_D1P/N

IN_D0P/N

IN_CLKP/N

x

x

DP159

DP SINK

100nF

OUT_D2P/N

OUT_D1P/N

OUT_D0P/N

OUT_CLKP/N

100F

100nF

100nF

ML0P/N

ML1P/N

ML2P/N

ML3P/N

100nF

100nF

100nF

100nF

Optional if already present

At DisplayPort Source.

50

50

50

50

3.3V

3.3V

3.3V

3.3V

Place Close to DP159

ML0P/N

ML1P/N

ML2P/N

ML3P/N

Local I

www.ti.com

2.3

DisplayPort Input and Output Implementation

The DP159 has DisplayPort++ receivers (IN[3:0]) and TMDS transmitters (OUT[3:0]). Because the DP159

receivers are DisplayPort++, there is nothing special required to connect the DP159’s to a DisplayPort

source. The DP159 transmitters are TMDS, and therefore, must be terminated to 3.3 V through a 50-

Ω

resistor. The 50-

Ω resistors must be placed as close to the DP159 pins are possible. Because DisplayPort

is a AC-coupled interface, 100-nF capacitors must be inserted after the 50-

Ω termination but before the

DisplayPort sinks input. To confine the impedance discontinuities caused by pads of the resistor and

capacitor, it is recommended to place the AC capacitors closer to the resistors.

Figure 4. DisplayPort Main Link Implementation

2.4

Output VOD Control

As previously mentioned, the DP159 outputs are TMDS transmitters, and therefore, not DisplayPort

compliant. The DP159 output voltage swing level is determined directly by value of the resistor used on

the VSADJ pin and by the VSWING register. The recommend value of 4.62 K

Ω produces a typically peak-

to-peak voltage swing of around 1400 mV. The value of the resistor can be reduced to produce a larger

voltage swing or increased to produce a smaller voltage swing.

Figure 5. VOD vs VSADJ Resistance

NOTE:

Note this chart assumes HDMI termination (single 50-

Ω to 3.3 V). The external 50-Ω plus the

internal FPGA termination reduces the VOD by as much as 40%.

4

DP159 as DisplayPort Retimer

SLLA358 – December 2015

Submit Documentation Feedback

Copyright © 2015, Texas Instruments Incorporated