Hannon S. Yourke

Oral History – (Continued)



Oral History – Hannon S. Yourke

Historic Audio Recordings


Describing His Early Work on Transistors at MIT in 1953.

Yourke Audio Clip #1


Joining the IBM Transistor Circuits Group in 1955 and Developing Current Steering Logic.

 Yourke Audio Clip #2


Working at IBM with Early Germanium Transistor Types, including

 Surface Barrier and Drift.

Yourke Audio Clip #3


Describing the First IBM Machines to use ECL Logic.

Yourke Audio Clip #4


Describing the ECL Patent, IRE Paper and Subsequent Widespread

 Use of ECL.

Yourke Audio Clip #5



Go To Yourke Oral History, Page 5






The Enduring Legacy of Transistor Current Switching Circuits


The following observations, and associated references, have been included in this Oral History in order to provide a current perspective on the historical importance of Hannon Yourke’s pioneering work on the first transistor current switching/ECL circuits.  


1. Summary Observation: The high performance computer industry was dominated for many years by bipolar ECL based vector processors until the mid 1990s, when CMOS performance finally began to compete. “The Recent Revolution in High-Performance Computing”, Horst D. Simon, Materials Research Society, Vol 22, Oct 1997. 

LINK: ECL in High Speed Computing



2. Summary Observation:  Beginning in the 1960s, Motorola announced the MECL line of ECL based integrated circuits, becoming a leader in this high speed technology – target markets were supercomputers, automatic test equipment and disk drive electronics.  “GaAs ICs – they came, they went, they came”, George Rostky, EETimes Millennium 2000 Series, The Century of the Engineer: Misunderstood Milestones. 

LINK: George Rostky - GaAs ICs -  EETimes




3. Summary Observation: H.S. Yourke’s emitter coupled logic broke the nanosecond barrier for switching speed and was used pervasively in high speed computing for many years to follow. “First Bipolar ECL Logic Circuit, ISSCC 50th Anniversary Virtual Museum – a showcase of 70 outstanding ideas spanning 50 years of solid state circuits history” - IEEE International Solid-State Conference.

LINK: http://www.sscs.org/History/isscc50/micropr-logic/index.html





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