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18-1
tn1074_02.1
October 2011
Technical Note TN1074
Introduction
As Ball Grid Array (BGA) packages become increasingly popular and become more populated across the array
with higher pin count and smaller pitch, it is important to understand how they are affected by various board layout
techniques. This document provides a brief overview of PCB layout considerations when working with BGA pack-
ages. It outlines some of the most common problems and provides tips for avoiding them at the design stage. A key
challenge of adopting fine-pitch (0.8 mm or less) BGA packages is the design of a route fanout pattern that maxi-
mizes I/O utilization while minimizing fabrication cost. This technical note provides an overview of PCB design
examples provided by Lattice Semiconductor.
For more information and design examples see the PCB Design Support page at the Lattice Semiconductor web
BGA Board Layout Recommendations
In order to evenly balance the stress in the solder joints, Lattice recommends that PCB solder pads match the cor-
responding package solder pad type and dimensions. If a different PCB solder pad type is used, the recommended
pad dimension is based on an equivalent surface contact area.
Table 18-1. Lattice SMD/NSMD Pad Recommendations
1
0.4 mm
Ball Pitch
0.5 mm
Ball Pitch
0.8 mm
Ball Pitch
1.0 mm
Ball Pitch
1.27 mm
Ball Pitch
64, 132
ucBGA
25
WLCSP
56, 64,
100, 132,
144
csBGA
100, 256,
332
caBGA
100
fpBGA,
256 ftBGA
(Option 12)
256 ftBGA
(Option 2
3),
324 ftBGA,
144, 208, 256,
388, 484, 672,
676, 900, 1152,
1156 fpBGA
1020, 1152,
1704 Organic
fcBGA
272, 388
PBGA,
256, 352
SBGA
Package Solder Pad Type
SMD
NSMD
SMD
Nominal BGA package solder pad
diameter (mm)
0.27
0.25
0.35
0.50
0.55
0.65
0.73
Optimum PCB (SMD) Solder
Mask Opening (mm)
0.20
0.28
0.25
0.40
0.45
0.55
0.63
Optimum PCB (NSMD) Solder
Land Diameter (mm)
0.17
0.25
0.23
0.35
0.40
0.52
0.58
1. These Lattice recommended PCB design values will result in optimum Board Level Reliability (BLR) performance for each corresponding
package. Designers who use PCB design values which deviate from these recommendations should understand that the BLR performance
may be reduced.
2. ispMACH 4000, MachXO and LatticeXP2.
3. LatticeECP3 and MachXO2.
PCB Layout Recommendations
for BGA Packages