OPEN COLLECTOR DRIVER WITH WV/Wt CONTROL
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
The driver circuit shown is an open collector driver type which is designed to control down-going output transitions (WV/Wt O V/ns) by internal active feedback as_1.0 compared to external capacitive feedback. Circuit operation is as follows: For input A at a logical 0, transistors T2, T3 and T5 are off causing the output A to be at a logical l level as determined by the off chip resistor RPAC to voltage Vc. The base of transistor T4 will be at a voltage level of approximately +2.5 V, allowing T4 to conduct which, in turn, causes T6 and TFB to conduct. When on, the T6/TFB combination is designed to have equal emitter currents, with T6 operating in the unsaturated mode and TFB operating in the saturated mode.