Active balun for wideband applications

摘要

An active balun uses two inverters to produce a differential output from a single-ended input. A current source supplies current to both inverters and a current sink sinks current from both inverters. The inverters include bias resistors coupled between their inputs and outputs. A coupling capacitor couples the output of the first inverter to the input of the first inverter. Values of the bias resistors and the coupling capacitor may selected to assure stability of the active balun. The values may be programmable, for example, based on a desired operating frequency. The current source may be biased by a common-mode feedback circuit based on the common-mode voltage of the differential output.

主权项

1. An active balun for receiving a single-ended input and producing a differential output including a non-inverted output and an inverted output, the active balun comprising:
a current source having an output coupled to a first common node; a current sink having an output coupled to a second common node; a first inverter coupled between the first common node and the second common node and having an input coupled to the input of the active balun and an output coupled to the inverted output of the active balun; and a second inverter coupled between the first common node and the second common node and having an input coupled to the output of the first inverter and an output coupled to the non-inverted output of the active balun.