SN75LVPE802: PCIe GEN1 x1 redriver

Terry Wu2

Expert 2110 points

Part Number: SN75LVPE802
Other Parts Discussed in Thread: DS80PCI102

Hello Sirs,

Its urgent need your suggestions !

1.Need your help will SN75LVPE802 OK for PCIe GEN1 x1 (2.5Gbps)?

2.Per PCIe FR4 trace loss 0.25~0.35 dB/inch .

Would you provide me what's LVPE802 EQ gain for "1" . "0" and "NC" ?

Datasheet only provide PCIe GEN3 EQ .

3. Refer to another LVPE802 E2E . I see these words .

Is it not recommend only for PCIe GEN3 ? Or its including PCIe GEN1~3 ?

"I do not recommend the SN75LVPE802 for PCIe applications. Instead I recommend the DS80PCI102 or the DS125BR111."

TKS !

over 5 years ago

0 Lee Sledjeski over 5 years ago

TI__Mastermind 43795 points

Hi Terry,

1. I would not recommend the SN75LVPE802 for PCIe Gen 1 x1 applications.

2. The SN75LVPE802 gain at 2.5 Gbps is typically: NC = 0 dB, 0 = 2.5 dB, 1 = 6 dB

3. The statement includes PCIe Gen1/2/3. The lack of an integrated Rx Detect function can result in systems which will not operate.

Regards,

Lee

0 Terry Wu2 over 5 years ago in reply to Lee Sledjeski

Expert 2110 points

Hello Lee,

Thanks your comment !

Does this redriver( for PCIe GEN1 2.5G ) could cascade to get higher EQ gain ? TKS !

0 Lee Sledjeski over 5 years ago in reply to Terry Wu2

TI__Mastermind 43795 points

Hi Terry,

The DS80PCI102 has significant gain even at 2.5 Gbps. It is typically better to work with a single repeater. How much attenuation is expected in this application?

Regards,

Lee

0 Terry Wu2 over 5 years ago in reply to Lee Sledjeski

Expert 2110 points

Hello Lee,

Thanks your suggestion !

29 inch include two golden finger & connector . One redriver is not enough to cover this loss I believe.

If same condition for DS80PCI102 , what location will be better for redriver ? 16 pcs riser card have 1 pcs redriver (LVPE802)

Pls refer below picture. TKS !

0 Lee Sledjeski over 5 years ago in reply to Terry Wu2

TI__Mastermind 43795 points

Terry,

I would place the DS80PCI102 at the midpoint of each channel. I would estimate ~0.35 dB loss per inch

A single DS80PCI102 could compensate for this much attenuation.

Regards,

Lee

0 Terry Wu2 over 5 years ago in reply to Lee Sledjeski

Expert 2110 points

Hi Lee,
There's board space concern so that redriver put on riser card .
May I have your email to communicate more detail ? TKS !

0 Lee Sledjeski over 5 years ago in reply to Terry Wu2

TI__Mastermind 43795 points

Hi Terry,
lee.sledjeski@ti.com
Regards,
Lee

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SN75LVPE802: PCIe GEN1 x1 redriver