In certain embodiments, a multi-channel capacitive sensor for measuring capacitances of sense electrodes to a system reference potential comprises a sample capacitor having first and second terminals. The sensor comprises a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and comprises a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. A control circuit is operable to apply a drive signal to the first terminal of the sample capacitor and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes.