International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A programmable RF ASIC is described which provides most of the RF functions within a next generation S-band transponder for space applications. The unique 18-contact LCC device can be programmed to perform a variety of RF and analog functions. This single space qualified high speed bipolar "function toolbox" is used in 39 locations throughout the transponder to provide a flexible radio architecture. The ASIC design process, internal electrical design, circuit application, space environment performance, and RF testing of the RF ASIC are described. This proprietary part provides a space-qualified solution for RF circuitry that can be applied to a variety of space application products.