US PATENT SUBCLASS 326 / 74
.~.~.~ ECL to/from TTL

Current as of: June, 1999
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326 /   HD   ELECTRONIC DIGITAL LOGIC CIRCUITRY

62  DF  INTERFACE (E.G., CURRENT DRIVE, LEVEL SHIFT, ETC.) {3}
63  DF  .~ Logic level shifting (i.e., interface between devices of different logic families) {3}
68  DF  .~.~ Field-effect transistor (e.g., JFET, MOSFET, etc.) {4}
74.~.~.~ ECL to/from TTL

DEFINITION

Classification: 326/74

ECL to/from TTL:

(under subclass 68) Subject matter comprising the interfacing between an emitter-coupled logic device and a transistor-transistor logic device.

(1) Note. An emitter-coupled logic device is a nonsaturated bipolar logic device in which the emitters of the input logic transistors are coupled to the emitter of a reference transistor.

(2) Note. A transistor-transistor logic device has a forward-biased input transistor which is responsive to an input logic signal at each of its one or more emitters and with its collector being directly coupled to the base of an output transistor. In TTL, the base-collector junction of the input transistor (usually a multiemitter type) remains forward biased and in saturation region when the circuit is in either the "on" or "off" condition.