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US 2020/0051973 A1Published application
Tunable Capacitive Compensation for RF Switch FET Stacks
AssigneepSemi Corporation
InventorsEric S. Shapiro, Simon Edward Willard, Tero Tapio Ranta
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Abstract
Overcoming parasitic capacitances in RF integrated circuits is a challenging problem. The disclosed methods and devices provide solution to such challenge. Devices based on tunable capacitive elements that can be implemented with switch RF stacks are also disclosed.
Claims28
A Radio Frequency (RF) circuit comprising:
- (i) a top node and a bottom node;
- (ii) a switch stack comprising a series arrangement of a plurality of transistors coupled between the top node and the bottom node;
- (iii) one or more tunable capacitive elements partitioned into one or more sets of tunable capacitive elements, wherein:
- (a) each tunable capacitive element of the one or more tunable capacitive elements comprises a first terminal, a second terminal and is configured to receive a control signal;
- (b) a first terminal of each transistor of the switch stack is connected to first terminals of tunable capacitive elements of a corresponding set of tunable capacitive elements of the one or more sets of tunable capacitive elements;
- and
- (c) a second terminal of each transistor of the switch stack is connected to second terminals of tunable capacitive elements of a corresponding set of tunable capacitive elements of the one or more sets of tunable capacitive elements;
- wherein:
- control signals receivable by tuning capacitive elements of the one or more tunable capacitive elements are configured to control variable capacitances across the first and the second terminals of the tunable capacitive elements of the one or more tunable capacitive elements to adjust compensating capacitances across the first and the second terminals of the transistors of the plurality of transistors, thereby compensating parasitic capacitances of the RF circuit.
6 more elements
A method of capacitive compensation of parasitic capacitances comprising the steps of:
- providing a switch stack comprising a plurality of transistors;
- for each transistor of the switch stack:
- providing one or more tunable capacitive elements wherein each tunable capacitive element comprises a first terminal and a second terminal;
- connecting a first terminal of the transistor to first terminals of the tunable capacitive elements of one or more tunable capacitive elements;
- connecting a second terminal of the transistor to second terminals of the tunable capacitive elements of the one or more tunable capacitive elements;
- and
- tuning capacitances across the first terminals and the second terminals of the tunable capacitive elements of the one or more tunable capacitive elements, thereby adjusting a compensative capacitance across the drain-source of the transistor.
4 more elements
Dependencies are inferred from the claim text.