A method couples a first bias signal to first and second internal nodes via first and second resistors, couples a second bias signal to third and fourth internal nodes via third and fourth resistors, couples the first internal node to the second internal node via a switch of a first type, and couples the third internal node to the fourth internal node via a switch of a second type. The method further couples the first internal node to the third internal node via a first transmission gate, couples the second internal node to the fourth internal node via a second transmission gate, couples a first terminal to the first and third internal nodes via first and third capacitors, respectively, and couples a second terminal to the second and fourth internal nodes via second and fourth capacitors, respectively.