Community Translation: フラッシュメモリ用BGAパッケージの5x5ボールグリッドと6x4ボールグリッドの選択 - KBA236949
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For Infineon 65-nm flash memory devices, the Ball Grid Array (BGA) package comes with two types: FAB024 24-Ball 5x5 BGA package and FAC024 24-Ball 6x4 BGA package. The main difference between the same 24-Ball BGA packages is the arrangement of balls and pinout configurations.
The outer dimensions for the two packages are same for all 65-nm flash memory devices with 8.00 mm and 6.00 mm. However, as the ball arrays are different, the ball array dimensions are different. The 5x5 BGA package has 4.00 mm x 4.00 mm, while he 6x4 BGA package has 5.00 mm x 3.00 mm.
Figure 1 Ball array dimensions for 5x5 BGA package and 6x4 BGA package
Meanwhile, the 45-nm MIRRORBIT™ SEMPER™ NOR flash supprts only the 24-Ball 5x5 BGA package. The package’s outer dimensions vary according to the density of the flash memory. For 512-Mb SEMPER™ NOR flash and lower densities, the outer dimensions are the same as the 65-nm flash memory with the VAA024 package, (8.00 mm x 6.00 mm). For 1 Gb and above densities, the outer dimensions are slightly bigger with the VAC024 8.00 mm x 8.00 mm package owing to the die size. SEMPER™ NOR flash can be made in monolithic single die up to 1 Gb density. However, the 1-Gb single die does not fit into the traditional 8.00 mm x 6.00 mm BGA package.
See Chapter 10, Package diagrams in the SEMPER™ NOR flash datasheet (Doc. No. 002-12345) for the dimensions.
Figure 2 BGA package 24-ball 6x8 mm and 24-ball 8x8 mm
When choosing the type of BGA package, the 24-ball 5x5 BGA package is a better choice considering the flash memory family migration. Even though the 65-nm flash memory supports both the 5x5 ball array and the 6x4 ball array and 45-nm SEMPER™ NOR flash supports only the 5x5 ball array, selecting the 5x5 BGA package gives flexibility in choosing the NOR flash.
Furthermore, when there is any future plan in migration to a higher density, SEMPER™ NOR flash has a broader portfolio up to 4 Gb. If the 8x8 mm space of high-density SEMPER™ is secure in the PCB design, the flash memory can be a drop-in replacement with the same schematic.