RF power amplifier
View Patent ↗An RF power amplifier includes a plurality of amplifier cells. Each amplifier cell includes a bipolar transistor and a base circuit that comprises an RF coupling capacitor, a bias resistor, a base capacitor, and a base resistor. The base circuit transmits DC bias current and an RF signal to the base of the bipolar transistor to provide a selectable frequency response. The base circuit may be implemented using a structure of stacked capacitors.
1. An RF power amplifier comprising:
a plurality of amplifier cells, each amplifier cell comprising a bipolar transistor and a base circuit,
each bipolar transistor including a collector coupled to an output node, including a base, and including an emitter coupled to a ground node,
each base circuit including an RF input node for receiving an RF signal, including a bias voltage node for receiving a bias voltage, and including a base node coupled to the base of the bipolar transistor, each base circuit comprising a parallel resistor-capacitor circuit including a first node coupled to said bias voltage node and said RF input node, and including a second node coupled to said base node, and wherein the base circuit includes a first circuit to control sub-harmonics of the bipolar transistor and a second circuit to provide ballast to control current collapse of the bipolar transistor.
2. An RF power amplifier comprising:
a plurality of amplifier cells, each amplifier cell comprising a bipolar transistor and a base circuit;
each bipolar transistor including a collector coupled to an output node, including a base, and including an emitter coupled to a ground node;
each base circuit including an RF input node for receiving an RF signal, including a bias voltage node for receiving a bias voltage, and including a base node coupled to the base of the bipolar transistor;
wherein each base circuit comprises:
a first capacitor including a first node coupled to the RF input node and including a second node;
a first resistor including a first node coupled to the bias voltage node and including a second node coupled to the second node of the first capacitor;
a second capacitor including a first node coupled to the second node of the first capacitor and including a second node coupled to the base of the bipolar transistor; and
a second resistor including first and second nodes coupled to the respective first and second nodes of the second capacitor.
3. The RF power amplifier of claim 2 wherein the collectors of the bipolar transistors are coupled to a collector node.
4. The RF power amplifier of claim 2 wherein the first and second capacitors of the base circuits include a structure of stacked capacitors.
5. The RF power amplifier of claim 4 wherein one plate of the first or second capacitor is formed by a metal layer that is the same layer that forms a collector terminal of the bipolar transistor.
6. The RF power amplifier of claim 1 wherein at least two amplifier cells are arranged as a pair, the emitters of the transistors of the pair being configured as emitter fingers.
7. An RF power amplifier comprising:
a bipolar transistor including a collector coupled to an output node, including a base, and including an emitter coupled to a ground node, and
a base circuit including an RF input node for receiving an RF signal, including a bias voltage node for receiving a bias voltage, and including a base node coupled to the base of the bipolar transistor, the base circuit comprising a parallel resistor-capacitor circuit including a first node coupled to said bias voltage node and said RF input node, and including a second node coupled to said base node, and wherein the base circuit includes a first circuit coupled to the base of the bipolar transistor to control sub-harmonics of the bipolar transistor and includes a second circuit coupled to the base of the bipolar transistor to provide ballast to control current collapse of the bipolar transistor.
8. An RF power amplifier comprising:
a bipolar transistor including a collector coupled to an output node, including a base, and including an emitter coupled to a ground node; and
a base circuit including an RF input node for receiving an RF signal, including a bias voltage node for receiving a bias voltage, and including a base node coupled to the base of the bipolar transistor,
wherein the base circuit comprises:
a first capacitor including a first node coupled to the RF input node and including a second node;
a first resistor including a first node coupled to the bias voltage node and including a second node coupled to the second node of the first capacitor;
a second capacitor including a first node coupled to the second node of the first capacitor and including a second node coupled to the base of the bipolar transistor; and
a second resistor including first and second nodes coupled to the respective first and second nodes of the second capacitor.
9. The RF power amplifier of claim 2 , wherein at least two amplifier cells are arranged as a pair, the emitters of the transistors of the pair being configured as emitter fingers.
10. The RF power amplifier of claim 1 ,
wherein each base circuit comprises:
a first capacitor including a first node coupled to the RF input node and including a second node coupled to the first node of the parallel resistor-capacitor circuit; and
a first resistor including a first node coupled to the bias voltage node and including a second node coupled to the first node of the parallel resistor-capacitor circuit;
wherein the parallel resistor-capacitor circuit comprises:
a second capacitor including first and second nodes coupled to the respective first and second nodes of the parallel resistor-capacitor circuit; and
a second resistor including first and second nodes coupled to the respective first and second nodes of the second capacitor.
11. The RF power amplifier of claim 7 ,
wherein the base circuit comprises:
a first capacitor including a first node coupled to the RF input node and including a second node coupled to the first node of the parallel resistor-capacitor circuit; and
a first resistor including a first node coupled to the bias voltage node and including a second node coupled to the first node of the parallel resistor-capacitor circuit;
wherein the parallel resistor-capacitor circuit comprises:
a second capacitor including first and second nodes coupled to the respective first and second nodes of the parallel resistor-capacitor circuit; and
a second resistor including first and second nodes coupled to the respective first and second nodes of the second capacitor.