AN2866 Freescale Semiconductor / Motorola, AN2866 Datasheet - Page 7

• Manufacturer Part Number: AN2866
• Description: Migrating from the MC68332 to the ColdFire MCF523x
• Manufacturer: Freescale Semiconductor / Motorola

The most evident advantage of the MAPBGA versus the QFP is the savings in board real estate. Most
BGAs are typically 20-25% smaller than their QFP counterparts. For the MAPBGA package, the entire
surface of the die, rather than just the edges, can be used for interconnection. When the total board area
required to place and route the package is taken into account, the MAPBGA can reduce size by as much
as 50%.
Lead pitch is a major consideration when working with high pin count QFPs. For these packages, the lead
pitch can be as fine as 0.64 mm. The BGA package with the same number of pins is easier to mount, since
the lead pitch is wider than a QFP package. BGAs are also less fragile and easier to handle both before and
during assembly. The placement operation for this package is usually far easier and more reliable than for
fine-pitch QFPs.
BGAs also have higher assembly yields. For example, BGAs typically have less than 5 parts per million
joints (ppmj) compared to the 50–100 ppmj of QFP devices. BGAs have higher assembly yields than QFPs
for the following reasons:
In general, BGAs have better electrical and thermal properties than their QFP counterparts. The long
fingers of the QFP lead frame make it more inductive than shorter ones. Additional enhancements can be
made to the BGA package by adding metal layers for power and ground.
Freescale Semiconductor
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No bent leads or coplanarity problems
Self-aligning on solder pads
Solder balls are always solderable (unlike plated leads)
Easy solder paste printing
Large pitch: 1.0 mm, 1.5 mm, 1.27 mm
Large ball diameter sizes: MAPBGA 19.68 mils
Figure 3
28x28mm X-Y dimensions
illustrates the differences between the QFP and the MAPBGA.
0.64mm lead pitch
4.07mm height
144 pin QFP
Migrating from the MC68332 to the ColdFire
784mm
Figure 3. Customer Board Area Reduction Example
2
®
MCF523x, Rev. 1.0
17x17mm X-Y dimensions
256 pin MAPBGA
1.00mm ball pitch
1.60mm height
289mm
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area
Device Differences
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