SN75LVPE5421: schematic check

GARETH OU

Guru 12820 points

Part Number: SN75LVPE5421

Could you help check the below SN75LVPE5421/12 schematic and any need to adujst ,Thanks

SN75LVPE5421 Check.pdf

Other questions

1. The block diagram is as follows: CPU PEG x16 Gen5 signal connected to Pciex16 / Pciex8 (optional)

peg x16 gen5.jpg

2. Layout guide notes: Currently, the impedance is 85 ohms. What is the maximum number of VIA chips that can be installed? What is their length? Please provide further assistance.

3. Do I need to add capacitors to the TX/RX signals of the connector after the SN75LVPE5421?

1 day ago

0 Charles 17 hours ago

TI__Expert 8453 points

Hi Gareth,

1. Please help fill out the schematic review checklist. I'll check again after and answer questions:

SN75LVPE5421_Schematic_Checklist (1).xlsx SN75LVPE5412_Schematic_Checklist (4).xlsx

2. Generally, use maximum of 2 vias. Please ensure to provide ground vias around signal vias. Ensure signal vias are back drilled. Please see layout guide for more info:

https://www.ti.com/lit/an/snla426/snla426.pdf

3. Each PCIe channel (TX to RX) requires a single ac coupling capacitor:

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1498356/faq-ds320pr810-how-should-pcie-signals-be-ac-coupled?tisearch=e2e-sitesearch&keymatch=ac%20coupling%20caps%20ds320pr410#

Best,

Charles

Interface

Interface forum

SN75LVPE5421: schematic check