High-Speed MSI Current-Mode Logic Circuits Implemented with Heterojunction Bipolar Transistors

Abstract

The first medium-scale integrated (MSI) Current-Mode Logic circuits implemented with heterojunction bipolar transistors are reported. MSI circuits consisting of up to 280 HBTs were designed and fabricated. These include an 8-bit universal shift register, a 3-bit register, and a gated full adder. The design considerations, HBT fabrication and device characteristics are described. Proper operation was observed at clock/input frequencies higher than 3 GHz for most of the circuits.