TUSB73x0 PCI Express Connection

Daisuke Maeda

Guru 20285 points

Other Parts Discussed in Thread: TUSB7340

Please see the TUSB73x0 Board Design and Layout Guidelines User's Guide (SLLU149A).

Section 8.1 describes that routing of the differential pair on the PCB will need to account for length mismatch in the package. For the length matching, a meander pattern is used at the device side on the PCB.

I guess that the meander pattern should not be used for the high speed interconnects such as PCIe.

In the PCI Express specifications, is it not defined that the length mismatch in the package is matched in silicon and the package design? Does TUSB73x0 meet the specifications?

For other PCIe devices on the customer board, I am concerned that the matching for length mismatch in the package is needed.

Best regards,

Daisuke

over 11 years ago

0 Elias Villegas M. over 11 years ago

TI__Guru* 76130 points

Hello,

I don't fully understand your question, but the internal bondwire length described on Section 8.1 should be taken into account.

When you are routing high-speed differential signals, both traces should be length matched, the total trace length shall include the internal bondwire of the device, that is why we specify the value of the bondwire length.

Yes, the TUSB7340 is PCIe compliant.

Regards.

0 Daisuke Maeda over 11 years ago in reply to Elias Villegas M.

Guru 20285 points

Hi ELIAS,

Thank you for your reply. Sorry for my poor English.

I understand that the internal bondwire length should be taken into account for TUSB73x0.

I think that the matching for internal length mismatch has been implemented in the package design for general PCIe device.

There are other PCIe devices on the customer board. is checking the internal bondwire length for other PCIe devices needed?

Best regards,

Daisuke

0 Elias Villegas M. over 11 years ago in reply to Daisuke Maeda

TI__Guru* 76130 points

Hello,

Yes, you should consider all the bondwire lengths involved on the differential routing.

Regards

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TUSB73x0 PCI Express Connection