IMPEDANCE CONTROL IN RADIO-FREQUENCY SWITCHES

• US 20170237432A1
• Filed: 02/10/2017
• Published: 08/17/2017
• Est. Priority Date: 02/11/2016
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: ROY, Ambarish, BLIN, Guillaume Alexandre
• Granted Patent: US 10,056,901 B2
• Time in Patent Office: Days
• CPC Class Codes: H03K 17/693 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors logic circuits H03K19/00; code converters H03M5/00, H03M7/00
• CPC Class Codes: H03K 19/0005 Modifications of input or output impedance
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption

Abstract

A radio-frequency switch includes a first field-effect transistor disposed between a first node and a second node, the first field-effect transistor having a source, a drain, a gate, and a body. The switch further includes a coupling path connected between the body of the first field-effect transistor and the gate of the first field-effect transistor, the coupling path including a diode. The switch further includes an adjustable impedance network connected between the body of the first field-effect transistor and a ground reference, the adjustable impedance network being configured to reduce radio-frequency distortion in the first field-effect transistor.

Claims

1. A radio-frequency switch comprising:

a first field-effect transistor disposed between a first node and a second node, the first field-effect transistor having a source, a drain, a gate, and a body;

a coupling path connected between the body of the first field-effect transistor and the gate of the first field-effect transistor, the coupling path including a diode; and

an adjustable impedance network connected between the body of the first field-effect transistor and a ground reference, the adjustable impedance network being configured to reduce radio-frequency distortion in the first field-effect transistor.

2. The radio-frequency switch of claim 1 wherein the adjustable impedance network is configured to present a first impedance when the first field-effect transistor is transmitting a signal having a first frequency and present a second impedance when the first field-effect transistor is transmitting a signal having a second frequency higher than the first frequency.

3. The radio-frequency switch of claim 1 wherein the first field-effect transistor is a silicon-on-insulator field-effect transistor.

4. The radio-frequency switch of claim 1 wherein the adjustable impedance network includes a second field-effect transistor having a gate, a drain, and a source.

5. The radio-frequency switch of claim 4 wherein the second field-effect transistor is connected at one of the drain or source of the second field-effect transistor to the body of the first field-effect transistor and connected at the other of the drain or the source of the second field-effect transistor to the ground reference.

6. The radio-frequency switch of claim 4 wherein the second field-effect transistor is operable to provide a desired impedance for reducing undesired radio-frequency distortion in the first field-effect transistor at a frequency of operation.

7. The radio-frequency switch of claim 4 wherein the adjustable impedance network includes one or more resistors connected in series with the second field-effect transistor.

8. The radio-frequency switch of claim 4 wherein the adjustable impedance network includes one or more capacitors connected in series with the second field-effect transistor.

9. The radio-frequency switch of claim 1 wherein the adjustable impedance network includes a capacitor.

10. The radio-frequency switch of claim 9 wherein the capacitor is connected at a first end to the body of the first field-effect transistor and at a second end to the ground reference.

11. The radio-frequency switch of claim 1 wherein the adjustable impedance network includes a capacitor connected in series with an inductor.

12. The radio-frequency switch of claim 1 wherein the adjustable impedance network includes a plurality of capacitors configured to be selectively coupled to the body of the first field-effect transistor using a network of switches.

13. A method for fabricating a semiconductor die, the method comprising:

providing a semiconductor substrate;

forming a first field-effect transistor on the semiconductor substrate, the first field-effect transistor having a source, a drain, a gate, and a body;

coupling the body of the gate of the first field-effect transistor using a coupling path that includes a diode; and

forming an adjustable impedance network on the semiconductor substrate connected between the body of the first field-effect transistor and a ground reference, the adjustable impedance network being configured to reduce radio-frequency distortion in the first field-effect transistor.

14. The method of claim 13 further comprising forming an insulator layer between the first field-effect transistor and the semiconductor substrate.

15. The method of claim 13 wherein the adjustable impedance network includes a second field-effect transistor having a gate, a drain, and a source, the second field-effect transistor being connected at one of the drain or source of the second field-effect transistor to the body of the first field-effect transistor and connected at another of the drain or source of the second field-effect transistor to the ground reference.

16. The method of claim 13 wherein the adjustable impedance network includes a capacitor connected at a first end to the body of the first field-effect transistor and at a second end to the ground reference.

17. The method of claim 13 wherein the adjustable impedance network includes a capacitor connected in series with an inductor.

18. A radio-frequency switch module comprising:

a packaging substrate configured to receive a plurality of components;

a semiconductor die mounted on the packaging substrate, the semiconductor die including a first field-effect transistor having a gate, a drain, a source, and a body;

a coupling path connected between the body of the first field-effect transistor and one of the source, the drain, and the gate of the first field-effect transistor, the coupling path including a diode; and

an impedance control circuit connected between the body of the first field-effect transistor and a ground reference, the impedance control circuit being configured to reduce radio-frequency distortion in the first field-effect transistor.

19. The radio-frequency switch module of claim 18 wherein the impedance control circuit includes a second field-effect transistor having a gate, a drain, and a source.

20. The radio-frequency switch module of claim 19 wherein the second field-effect transistor is connected at one of the drain or source of the second field-effect transistor to the body of the first field-effect transistor.

21. The radio-frequency switch module of claim 18 wherein the impedance control circuit includes a capacitor connected to the body of the first field effect transistor.

22. The radio-frequency switch module of claim 18 wherein the impedance control circuit includes a capacitor connected in series with an inductor.