Migrating from FM20L08 to FM28V100

Migrating from FM20L08 to FM28V100
AN-106

Migrating from FM20L08 to FM28V100
How to Create a PCB for Compatibility


DESCRIPTION
The FM20L08 (128Kx8) and FM28V100 (128Kx8) devices are offered in the 32-pin TSOP-I package.
The package body size is 8.0 x 13.4 mm and the pin pitch is 0.5 mm. The two devices are not pin
compatible with each other, but they are very similar. It is possible to design a pc board such that either
device can populate the board.

PCB LAYOUT CONSIDERATIONS
The two parts have slightly different pin assignments. The differences are pins 6 and 9. The FM20L08
has a DNU on pin 6 and /LVL on pin 9. The FM28V100 has CE2 on pin 6 and NC on pin 9. Most
designs do not use the /LVL pin (FM20L08). The board may be layed out such that pin 9 is left floating.

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