Power amplifier with distributed capacitor
AssigneeMediatek Incorporation
InventorsJin Wook Cho, Hongxi Xue
Life of this patent
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Abstract
A power amplifier integrated circuit includes a plurality of heterojunction bipolar transistors having a plurality of bases, a plurality of ballast resistors, and a capacitor. Each ballast resistor is connected between a base of the transistor and a DC node to which a DC voltage is applied. The capacitor is connected between an RF node, which supplies an RF signal, and the plurality of bases of the transistors. The capacitor provides a distinct path for the RF input signal having a substantially high capacitance, so that the RF input signal does not suffer significant signal loss.
Claims13
A power amplifier integrated circuit consisting essentially of:
- a plurality of transistors each comprising a base;
- a plurality of ballast resistors corresponding to the plurality of transistors, each ballast resistor having a first terminal and a second terminal, the first terminal connected to the base of the corresponding transistor;
- a DC node to which the second terminals of the plurality of ballast resistors are connected;
- an RF node for supplying an RF input signal;
- and
- a capacitor having a third terminal and a fourth terminal, the third terminal connected to the RF node and the fourth terminal connected to the plurality of bases.
A semiconductor device comprising:
- a semiconductor substrate;
- a DC node for receiving a DC voltage;
- an RF node for receiving an RF input signal;
- a plurality of transistors formed on the semiconductor substrate, each of the plurality of transistors having a base;
- a plurality of ballast resistors formed on the semiconductor substrate and corresponding to the plurality of transistors, each ballast resistor having a first terminal and a second terminal, the first terminal connected to the base of the corresponding transistor, the second terminal connected to the DC node;
- and
- a capacitor formed on the semiconductor substrate, the capacitor having a third terminal and a fourth terminal, the third terminal connected to the RF node and the fourth terminal connected to more than one of the plurality of bases.
Dependencies are inferred from the claim text.