To be more general, we will refer to the CY2305SXC-1 as the CY2305. Likewise, the CY2305CSXC-1 will be called the CY2305C.
The CY2305 and CY2305C have the same footprint and functionality. Most of the specifications are the same. The differences are that the CY2305C has faster rise & fall times and slightly lower jitter and output-to-output skew than the CY2305. When the specification differences are not important, customers are encouraged to use the CY2305C in new designs.
Product Change Notice (PCN) 084713 describes that the CY2305 has been qualified for production in a new fabrication facility. The part numbers CY2305E are temporary, and represent CY2305 devices produced at the new fab location. They are only to be used if a customer wants to order samples of the CY2305 produced at the new fab location. We are not making a permanent switch to the CY2305E part numbers. We chose not to add them to the data sheets because they are temporary.
The original part numbers such as CY2305SXC-1 are still valid and will continue to be valid. Customers can continue to order the original part number and are not required to order any of the CY2305E samples. PCN 084713 serves as the documentation of the CY2305E part numbers.