General Guidelines

Efinix recommends that you follow these general guidelines when laying out your board.

PCB Dielectric

The dielectric constant of PCB materials for most memory applications is 3.6 to 4.5, varying with frequency, temperature, material, and the resin-to-glass ratio.

FR-4, a commonly used dielectric material, averages 4.1 with signalling at 1 GHz. FR-4 is a copper-clad laminate that is adequate for most applications.

Power Design

  • Route GND and VCC as planes.
  • Route VTT as islands.

Decoupling Recommendations

  • Use a high-accuracy capacitor to minimize inductance.
  • Place every voltage supply decoupling close to pull-up resistors.
  • Place address and control signals close to pull-up resistors.
  • For the VDD and VDDQ power supplies, use > 0.1 μF decoupling capacitor to reduce noise.