Hello everyone,
I recently completed the layout of a DDR3 memory interface for the STM32MP157FAC1 SoC using KiCad, based on guidelines from the DDR3 and STM32 hardware design application notes.
Key design highlights:
- Impedance control:
• 55 Ω ±10% for single-ended signals
• 100 Ω ±10% for differential pairs (DQS and CLK) - Length matching:
All critical signals—including CLK, DQS, DQ, address, and control lines—were matched within a 1.016 mm tolerance. - Data lane configuration:
• Byte 0: DQ[7:0], DQM0, DQS0_P/N
• Byte 1: DQ[15:8], DQM1, DQS1_P/N
• DQ signals were length matched with their corresponding DQS strobe signals within each byte lane. - Control signals:
RAS#, CAS#, WE#, CS#, CKE, and ODT are length matched with the differential clock (CLK_P/N). - Address lines:
Grouped and length matched among themselves to ensure timing alignment.
I would truly appreciate any feedback ,
Thank you so much for your time and support.