This is a conventional cascode configuration amplifier:
Here is an excerpt in "Self-biased cascode RF power amplifier in sub-micron technical field" .
http://www.google.com.vn/patents/US6515547
Here is an excerpt in "Self-biased cascode RF power amplifier in sub-micron technical field" .
http://www.google.com.vn/patents/US6515547
I don't understand why the cascode configuration can solve the problem gate-drain breakdown. Please explain.In state of the art MOS power amplifiers, the drain-gate voltage can often go as high as three times the supply voltage. This poses a limitation on the maxi-mum supply voltage that can be used in such amplifiers and still avoid gate-drain breakdown. One method of ameliorating this problem is to utilize the familiar cascode structure in the amplifier, in which, in a two-transistor example, one transistor is in the common-source configu-ration and another is in the common gate configuration. In such cascode configuration the signal swing drops be-tween the two transistors and therefore lessens the gate to drain breakdown problem. Such cascode transistors appear as a four terminal device: two gates, one source
and one drain.
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