In this paper, we present a prototype ultra-fast hopping spread spectrum transceiver front-end that realizes 20 dB of processing gain in the RF before any amplification occurs along the receiver chain. This means that a narrow-band in-band interferer is rejected by 20 dB before the low noise amplifier (LNA). The correlation function at RF is made possible by using a passive mixer-first receiver architecture that is driven by an ultra-fast hopped local oscillator (LO) signal. The 47 MHop/s LO is generated using an all-digital oscillator circuit that is followed by a memoryless digital-to-analog converter (DAC). The prototype chip fabricated in a Taiwan Semiconductor Manufacturing Company (TSMC) 65 nm RF CMOS process occupies 3.1 mm2 of active area. The receiver and the transmitter each consume ≈25 mW from a 1 V power supply.