An exponentially scaling C-2C switched-capacitor (SC) ladder is proposed for millimeter-wave digitally controlled oscillators (DCOs) to achieve high-frequency resolution with small chip area. The 65-nm-CMOS DCO prototype measures a frequency resolution of 4 Hz over a frequency range of 14.2%, from 54.79 to 63.16 GHz, with a phase noise at 1-MHz frequency offset of -90.7 to -94.1 dBc/Hz while consuming 18 mW, corresponding to an FOM_T from -176.6 to -180 dB. The DCO occupies a core area of 0.10 mm², with only 0.012 mm² for the C-2C SC ladder.