초록 ▼

A driver circuit for use in testing either ECL (emitter-coupled logic) or TTL (transistor-transistor logic) devices. The circuit has a pair of variable reference voltages (VH,VL) for determining the logic levels 0 and 1. The circuit also has two termination networks (8,9) for ECL and TTL, which are

A driver circuit for use in testing either ECL (emitter-coupled logic) or TTL (transistor-transistor logic) devices. The circuit has a pair of variable reference voltages (VH,VL) for determining the logic levels 0 and 1. The circuit also has two termination networks (8,9) for ECL and TTL, which are selectively connected to the output of the driver circuit according to the value of one of the reference voltages (VL). Preferably the circuit is formed as a hybrid network in which transistors from the same semiconductor slice are mounted on the same ceramic substrate.

대표청구항 ▼

A driver circuit for automatic digital testing apparatus, comprising a switching circuit; a first signal input terminal by which a control signal may be applied to the switching circuit to cause the latter to adopt a related switching state, the switching circuit having a line terminating at a termi

A driver circuit for automatic digital testing apparatus, comprising a switching circuit; a first signal input terminal by which a control signal may be applied to the switching circuit to cause the latter to adopt a related switching state, the switching circuit having a line terminating at a terminal for connection to the circuit to be tested; second and third signal input terminals to the switching circuit, first voltage producing means for producing a first variable reference voltage connected with the second input; second voltage producing means for producing a second variable reference voltage connected with the third input; first and second circuit to be tested matching circuits having different operational characteristics, a matching circuit control unit connected to control operation of the first and second matching circuits, said control unit being responsive to one of the reference voltages for connecting one or the other of the matching circuits to the output terminal in accordance with the magnitude of that reference voltage, said switching circuit being such as to produce at the output terminal a binary output signal having two levels representing the binary digits 0 and 1, the levels being determined respectively by the two reference voltage levels.