The Department of Defense's Defense Advanced Research Projects Agency (DARPA) has supported research and development (R&D) in microelectronics for many decades. DARPA is interested in ways to improve engagement with and support the microelectronics industry, potentially through establishing a public-private partnership (PPP) to advance R&D and technology development goals. To support these interests, DARPA requested the IDA Science and Technology Policy Institute (STPI) identify and analyze prior and ongoing PPPs to inform their efforts to establish a new PPP. DARPA anticipates a new PPP could advance microelectronics R&D and technology development potentially by supporting infrastructure to meet prototyping needs across the industry. Specifically, the study team set out to identify lessons learned related to the design and implementation of past and ongoing PPPs and develop options for structuring a new PPP, and propose options for a new microelectronics PPP for DARPA to consider.