Varactor trimming for MMICs

摘要

Varactors are incorporated in a monolithic microwave integrated circuit (MMIC) to provide voltage-programmable impedance matching at inputs and/or outputs. This permits the impedance variations normally caused by manufacturing variations in (e.g.) doping or epitaxial thickness to be easily compensated by adjusting the varactor bias, after all major manufacturing steps are completed.PPIntegrated varactors are also used to provide temperature compensation in an MMIC. A temperature-sensitive voltage is generated off-chip and supplied to each on-chip varactor. Each varactor may include a respective voltage-shifting network, so that different varactors implement different capacitance (temperature) functions, to optimally compensate different portions of the MMIC.