Patent ID: 8179186

Claim:
A method for reducing off-state leakage current in a differential switching device, the method comprising: receiving an analog differential input signal at a differential input of the differential switching device, the differential input being coupled to each of a primary switch and a dummy switch, wherein each of the primary and dummy switches includes a differential pair of transistors and the analog differential input signal is applied to the bases or gates of the transistors; in an enabled-state of the differential switching device, passing the analog differential input signal to a differential output of the primary switch, wherein in the enabled-state both transistors of the primary switch differential pair intentionally conduct at the same time at least part of the time but one transistor of the pair conducts more than the other transistor; preventing the dummy switch from passing signals other than off-state leakage signals using a dummy current source operatively coupled to the dummy switch and set so that no intentional current flows through the dummy switch, wherein neither transistor of the dummy switch differential pair intentionally conducts; and in a disabled-state of the differential switching device during which a primary current source operatively coupled to the primary switch is set so that no intentional current flows through the primary switch, canceling off-state leakage current at a differential output of the differential switching device, by virtue of the differential output of the primary switch being coupled to the differential output of the differential switching device and the dummy switch having its differential output reverse-coupled to the differential output of the primary switch, wherein in the disabled-state neither transistor of the primary switch differential pair intentionally conducts.