Low noise differential amplifier
US4460872A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1981 |
| Grant date | Jul 17, 1984 |
| Priority date | — |
| Expiry date | Dec 3, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45498
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A low noise amplifier circuit (FIGS. 4 and 5) is disclosed including plural differential amplifiers having their inputs and outputs connected to common input and output lines (50, 52; 54, 56). In the disclosure, each differential amplifier is comprised of a pair of bipolar junction transistors (40, 42; 58, 60; 64, 66) of the same type. Parallel connecting of the differential amplifiers in the disclosed fashion reduces the Johnson noise introduced by the base spreading resistances of the individual transistors. Since differential amplifiers, per se, are connected in parallel rather than their component transistors, thermal runaway is not a problem.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.