Lattice has many parts that are dual marked and this causes confusion with customers. This post will help explain what dual marked parts are and how to tell if what was received was the correct part.
We will use the example of part number LC4128V-10TN128I. A customer ordered this part but felt they received the wrong one. They provide an image of the part markings. The markings were following:
Top line, LATTICE
Second line, LC4128V
Third line, 75TN128-10I.
Fourth line, B51BRR58
The second line indicates the series of the part, so in this case the series is LC4128V. The fourth line is the Lot number. The third line is the most important and lets us know what the part is.
The 75 and the 10I indicate that this part is dual marked. The 75 is the call out for part number LC4128V-75TN128C and the 10I is the call out for part number LC4128V-10TN128I.
The datasheet for this part lists the following message on page 74. _Note: ispMACH 4000 devices are all dual marked except the slowest commercial speed grade ispMACH 4000Z devices. For example, the commercial speed grade LC4128C-5T100C is also market with the industrial grade -75I. The commercial grade is always one speed grade faster than the associated dual mark industrial grade. The slowest commercial speed grade ispMACH 4000Z devices are marked as commercial grade only.
Not all Lattice parts are dual marked but many are and the datasheet is great resource to find out if your part might be.