The Design Of Single-Ended & Differential MMIC VCOs

This paper describes design techniques for both single-ended and differential VCOs, with examples shown fabricated in GaAs MMIC processes. Voltage Controlled Oscillators (VCOs) are widely used as signal sources in RF and microwave communication systems. Fully monolithic VCO ICs are rarely encountered as stand-alone components, mainly due to the low Q of the resonators and poor tuning performance of the available varactor technology. Their use in multi-function ICs is, however, now relatively common, as pressure to reduce the number of external components needed by the IC increases. This paper aims to show that the use of monolithic differential VCOs has several advantages in transceiver ICs over a conventional single-ended approach.