Question: Jim Keller is a microprocessor engineer most well known for his work at AMD and Apple, he was involved in designing which 32-bit package on package (PoP) system-on-a-chip (SoC) designed by Apple Inc. and manufactured by Samsung? 
Sentence (from "Jim Keller (engineer)"): From 2012 to 2015, he returned to AMD to work on the AMD K12 and Zen microarchitectures.
Relevant evidence: No