A 28 GHz Hybrid PLL in 32 nm SOI CMOS

A hybrid PLL is introduced, which features a simple switched resistor analog proportional path filter in parallel with a highly digital integral path. The integral path control scheme for the LC-tank VCO includes a novel linearly scaled capacitor bank configuration. In addition to the analog proportional path, the PLL includes a set of digital proportional path controls, so that the two approaches can be experimentally compared. At 28 GHz the RMS jitter is 199 fs (1 MHz to 1 GHz), phase noise is -110 dBc/Hz at 10 MHz offset. The 14 × 160 μm² 32 nm SOI CMOS PLL locks from 23.8 to 30.2 GHz, and draws 31 mA from a 1 V supply.