SN65DP159: DP159 X mode: frequency

shiwei luan

Part Number: SN65DP159

I am designing a circuit with DP159 in DisplayPort application. From Application Report SLLA358, "In X-Mode, the DP159 can support DisplayPort datarates up to 5.4Gbps (HBR2)."

I need to figure out the length matching and impedance matching settings in the PCB layout. Since DisplayPort has 4 data lanes with embedded clock, no dedicated clock lane, should I use 5.4GHz on these data lanes?

In other words, if the data lane is transmitting "010101......" sequence, the equivalent frequency is 5.4GHz?

Thank you

over 7 years ago

0 Michael.Walker over 7 years ago

TI__Mastermind 19720 points

The frequency of a signal is half of its data rate. This means that if the data rate is 5.4 Gbps the frequency is at 2.7 GHz.

0 JMMN over 7 years ago

TI__Guru 60870 points

Hi Shiwei,

Please be aware that to run the DP159 in x-mode requires an FPGA to control the retimer. It cannot be pin configured like the standard DP159 in DP++ to HDMI retimer / redriver mode applications.

Regards,
JMMN

0 shiwei luan over 7 years ago in reply to Michael.Walker

Intellectual 750 points

Could you provide more explanation or theories? Why it's 2.7GHz at 5.4 Gbpts data rate?

Thank you.

0 shiwei luan over 7 years ago in reply to JMMN

Intellectual 750 points

Thank you for reminding me this.

0 Michael.Walker over 7 years ago in reply to shiwei luan

TI__Mastermind 19720 points

The data rate is twice the frequency because there can be two bits of information for every period of the signal. see picture below for example. The red lines are the period of the frequency, the green lines are half of the period, the brown line is the signal, the bits above are the information transmitted.

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SN65DP159: DP159 X mode: frequency