| 摘要 |
A high speed bipolar noninverting current-mode logic AND gate is the basic building block for a current-mode logic family. The AND gate comprises a current steering differential pair of transistors, a pair of dual emitter input transistors, a dual emitter reference transistor, an output resistor and a fixed current source. The conducting state of the current steering transistor pair is so controlled that a logic "one" at the base electrodes of both input transistors produces a logic "one" at an output terminal taken from the collector electrode of the reference transistor. Further, a logic "zero" at both input transistors produces a logic "zero" at the output terminal and finally the condition of a "zero" at one input and a "one" at the other input produces a "zero" at the output. This result is attained as a consequence of control of the conduction state of the current steering pair so as to provide the same current level through the reference transistor for the "zero-one" input as for the "zero-zero" input, thus producing the noninverting AND function.
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