LFXP3E-4TN100C Lattice, LFXP3E-4TN100C Datasheet - Page 392

• Manufacturer Part Number: LFXP3E-4TN100C
• Description: IC FPGA 3.1KLUTS 62I/O 100-TQFP
• Manufacturer: Lattice

Specifications of LFXP3E-4TN100C

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PCB Layout Recommendations
Lattice Semiconductor
for BGA Packages
PCB cross-sectioning is another method used to verify BGA and PCB quality and reliability. After a new process
has been developed or changed or when qualifying a new vendor, it is a good practice to get physical information
from the vendor on their BGA reflow. When trace/space and drill or laser tolerances are nearing their limits, board
yield can be as be as low as 50% for the bare board fab. Cross-sections give you a good idea if the process is cor-
rect but do not guarantee each batch or each board design will behave the same way due to layout dimensions,
thermal issues, flux/paste and alignment, etc.
Figure 14-17 shows a BGA cross-section that uses a non-soldermask over bare copper-defined pad. (NSMD) pad.
Figure 14-17. BGA Cross-Section
Figure 14-18 shows “offset” micro via stack routing between layers.
Figure 14-18. Cross-Section of Micro Vias
High-resolution video cameras are used for edge inspection to verify ball seating, distortion, solder wetting, flow,
contaminates, etc. Figure 14-19 is a video view of a side/edge shot looking at BGA balls soldered down to the isp-
MACH 4000ZE Pico Evaluation Board (www.latticesemi.com/4000ze-pico-kit), an FR4 4-layer PCB.
14-17