Tektronix 11A33 Differential Comparator

As a differential amplifier, the 11A33 provides a balanced (+ and -) input for applications requiring rejection of a common-mode signal. The unit can reject up to 8 V pk-pk of common-mode signal with a CMRR of 10,000:1 from DC to 1 MHz, (derating to 500:1 at 20 MHz 1 V p-p) at a deflection factor setting of 1 mV/div. Differential DC offset is available to null out DC offsets between the two inputs. This offset capability can be used with DC coupling at 1 mV/div to measure a bipolar transistor's Vbe change from self-heating caused by signal changes.
 

As a comparator amplifier the 11A33 loses its differential capability, but provides an accurate (0.15%) positive or negative internal offsetting voltage covering the amplifier's common-mode signal range. This mode is also known as slideback comparison. A signal of up to ±8 V may be applied to an input at a deflection factor setting of 1 mV/div, and with an opposing VC (offset voltage), small segments of the signal may be observed.