Precision Tristate Driver
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
This precision tristate driver can sink or source current to one of two or more voltage levels. The driver is designed to drive an unterminated 50 L transmission line up to three feet and to deliver a very flat pulse with very fast transitions. Also, when the driver is inhibited, the output impedance is very high and looks like an open circuit. In the circuit operation, DATA and ENABLE signals enter an emitter-coupled logic block 13 where data is gated and timed for isolation amplifiers A1, A2, A3 and A4 (Fig. 1). Typically, the pulse driver is operated by turning transistors Q1 and Q2 off just before transistors Q3 and Q4 turn on or vice versa.