At least a first capacitor is formed on a substrate and connected to a first differential node of a differential circuit, and the first capacitor may be variable in capacitance. A second capacitor is formed on the substrate and connected to a second differential node of the differential circuit, and the second capacitor also may be variable. A third capacitor is connected between the first differential node and the second differential node, and is formed at least partially above the first capacitor. In this way, a size of the first capacitor and/or the second capacitor may be reduced on the substrate, and capacitances of the first and/or second capacitor(s) may be adjusted in response to a variable characteristic of one or more circuit components of the differential circuit.