WDC’s chip products come in 3 major package types: PDIP, PLCC, and QFP. The table below shows the package type for each part.
Understanding Identifying markings on WDC IC products
General Understanding of Date Coding:
Many manufactures include date codes on ICs to indicate when they were produced. These usually consist of the last two digits of the year plus two additional digits. The two additional digits most generally represent the week or month the IC was manufactured, depending on the company a code like “9501” could indicate the IC was made during the first week of 1995. These dates have very little meaning to the effectiveness of the parts performance to the general public. The importance of this information relates to the manufacturer as a way to identify runs of products which may contain abnormally high percentages of defects or other problems.
Understanding WDC Product Part numbers
Line 1: WDC Logo
Line2: WDC Part Number
Line 3: Wafer Lot Code
Line 4: Assembly Date Code
Understanding WDC Product Code Information
Lot # A1S0002 this is the Wafer lot number which reflects the production run of the wafer by TSMC. Wafers are produced and stored due to the requirements of production by TSMC. This code may be reflected on products with multiple date codes.
Date Code:  Year/Week [G018] Progate Serial number for tracking the line production