Wideband, variable gain amplifier
US6271726A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2000 |
| Grant date | Aug 7, 2001 |
| Priority date | — |
| Expiry date | Jan 10, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G3/3036
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplifier circuit including a novel degeneration input stage that permits a low Noise Figure and superior linearity to be achieved in combination. The amplifier is suitable for use in fully integrated direct-conversion tuner circuits, and provides continuously variable gain functionality implemented by steering current away from an output load of the amplifier through differential transistor pairs located in the current signal paths of an input stage. Voltage headroom problems are avoided by placing the attenuation resistors of the degenerated input stage in the signal path, such that there is little or no DC voltage drop across the resistors. Further, this arrangement permits very accurate on-chip matching to an off-chip signal source. The distribution of IP3 values over the gain range of the amplifier, as well as gain and NF characteristics, are dependent on resistor ratios rather than absolute values. These amplifier characteristics are thus largely temperature and process independent. In one embodiment of the invention, separate voltage supplies, ground connections and bias circuits are provided for different portions of the circuitry in order to improve noise immunity and r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.