SN65DP159: SN65DP159 trace length(max/min)

Sean Liao (Yu-Sheng)

Expert 4860 points

Part Number: SN65DP159

Hi sir,

What's CPU to SN65DP159 trace length(max/min), and the SN65DP159 to HDMI CONN. Trace length(max/min)?

Thanks a lot!

2 months ago

0 David (ASIC) Liu 2 months ago

TI__Guru**** 187011 points

Hi,

Maximum supported trace length will be impacted by trace impedance, length matching, number of vias, etc. so it is difficult to guarantee a specific real world trace length based on optimal lab testing.

For input trace length, assume 0.8dB/in loss at 6Gbps, trace length can be 15in. The output trace length will be 1in.

Thanks

David

0 Sean Liao (Yu-Sheng) 2 months ago in reply to David (ASIC) Liu

TI__Expert 4860 points

Hi David,

We have a question about min trace length requirement.

Due to we want to support HDMI 2.0, and the DDI trace length from CPU to SN65DP159 around 1123mil max.

Is there any concern to use the SN65D159?

0 J 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Mastermind 26771 points

Hi Sean,

What is their DP159 to HDMI port trace length? 1123 mil on the RX side is pretty short.

Best,
J

0 Sean Liao (Yu-Sheng) 2 months ago in reply to J

TI__Expert 4860 points

Hi J,

Due to you didn’t define the min for the trace length.

Do you have any comment? we need support the HDMI 2.0.

Thanks a lot!

0 J 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Mastermind 26771 points

Hi Sean,

There is no defined “min” trace length. It depends on how much loss there is on the receiver side.

The loss depends on the board material, trace length, and the speed of the signal. What is the board material? Is it FR4?

Best,

0 Sean Liao (Yu-Sheng) 2 months ago in reply to J

TI__Expert 4860 points

Hi J,

J said:
What is their DP159 to HDMI port trace length? 1123 mil on the RX side is pretty short.

The trace length from DP159 to HDMI connector around 190+68.8=258.8mil

Is this okay?

Thanks a lot!

0 Sean Liao (Yu-Sheng) 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Expert 4860 points

J said:
What is the board material? Is it FR4?

Hi J,

It's IT-158

Thanks a lot!

0 J 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Mastermind 26771 points

Hi Sean,

1 in is definitely a lot shorter than a typical use case, but there should not be any issue as long as the customer keeps the EQ setting for the redriver mode low or uses the retimer mode.

Best,

0 Sean Liao (Yu-Sheng) 2 months ago in reply to J

TI__Expert 4860 points

Hi J,

Pls help to review the placement and schematic, thanks a lot!

SN65DP159_for Sean review_20260225A.pdfhttps://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/B0781V100_5F00_0224.7z

0 David (ASIC) Liu 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Guru**** 187011 points

Sean

Please see attached for my schematic review comment and I am ok with the initial DP159 placement.

SN65DP159_for Sean review_20260225A_TI_Reviewed_02252026.pdf

Thanks

David

0 Sean Liao (Yu-Sheng) 2 months ago in reply to David (ASIC) Liu

TI__Expert 4860 points

Hi David,

Appreciate for the review. Pls kindly see the new schematic if it's good.

Thanks a lot!

ESD clamping voltage is too high, use an ESD with lower clamping voltage such as PUSB3FR4[customer] what is the impact?
What is the purpose of Q137?[Customer] the EC to DP159 I2C level shift.

SN65DP159_for Sean review_20260302A.pdf

0 David (ASIC) Liu 2 months ago in reply to Sean Liao (Yu-Sheng)

TI__Guru**** 187011 points

Hi,

ESD clamping voltage is too high, use an ESD with lower clamping voltage such as PUSB3FR4[customer] what is the impact?

If the ESD clamping voltage is too high, then the ESD diode will not clamp during an ESD event and all the ESD energy will damage the DP159.

I am also ok with the latest schematic.

Thanks

David

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SN65DP159: SN65DP159 trace length(max/min)