DDR4 PHY — Timing Closure

Problem

Close setup/hold across PVT corners on a 3200 MT/s DDR4 PHY with stringent jitter budget.

Approach

• 01Per-bit delay lines with calibration FSM.
• 02Multi-corner multi-mode (MCMM) sign-off across 12 corners.
• 03Hold fix with buffer tree insertion guided by useful-skew.

Results

• → WNS closed across all 12 corners.
• → Jitter < 18 ps RMS across PVT.
• → Write-leveling FSM converges in 6 cycles.

Screenshots