A Robust 43 GHz VCO in Standard CMOS for OC-768 SONET Applications

In this paper, we present a 43 GHz VCO in 0.13μm CMOS for use in SONET OC-768 optical networks. The design has a large tune range of 4.2%, which is sufficient to hold the design center frequency over anticipated process spread and temperature variation. A tuned output buffer is used to provide 1.3 Vp-p (single-ended) into a 90 fF capacitive load as is required when the VCO is used in typical clock and data recovery (CDR) circuits. Phase noise is -90 dBc/Hz at a 1 MHz offset from the carrier; this meets SONET jitter specifications. The VCO, including output buffers, consumes 14 mA from a 1 V supply and occupies 0.06 mm2 of die area