LNA with linearized gain over extended dynamic range
AssigneeInnophase, Inc.
InventorsNicolo Testi, Xi Li, Xuejun Zhang, Yang Xu
Life of this patent
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Abstract
A low noise amplifier including a variable gain amplifier stage configured to accept an input signal and to provide a load driving signal; a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component when the load driving signal is of a magnitude large enough to decreases a transconductance of the cross-coupled transistor pair; and, a controller circuit configured to tune the bandpass filter. The filter can be tuned in respect to the frequency and the quality factor Q.
Claims20
An apparatus comprising:
- a variable gain amplifier stage configured to accept an input signal and to provide a load driving signal;
- a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a resonant tank, a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair biased in a subthreshold region configured to add a transconductance component when the load driving signal is of a magnitude large enough to decrease the transconductance of the cross-coupled transistor pair;
- and,
- a controller circuit configured to tune the bandpass filter.
A method comprising:
- adjusting the gain of a variable gain amplifier stage;
- adjusting a resonant frequency and a Q of a tunable bandpass filter connected as a load to the variable gain amplifier stage, wherein the bandpass filter includes a cross-coupled transistor pair, and at least one cross-coupled compensation transistor pair;
- and,
- biasing the at least one cross-coupled compensation transistor pair in a subthreshold region.
A method comprising:
- adjusting, to a first frequency, a resonant frequency of a first low noise amplifier stage having a first variable gain amplifier stage and a first tunable bandpass filter;
- adjusting, to a second frequency offset from the first frequency, a resonant frequency of a second low noise amplifier stage having a second variable gain amplifier stage and a second tunable bandpass filter;
- biasing cross-coupled compensation transistor pairs in each of the first tunable bandpass filter and second tunable bandpass filter in a sub-threshold region to provide a compensation transconductance in the presence of large signals.
Dependencies are inferred from the claim text.