Switching device having a discharge circuit for improved intermodulation distortion performance

• US 9,685,943 B2
• Filed: 01/30/2015
• Issued: 06/20/2017
• Est. Priority Date: 07/07/2012
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Madan, Anuj, Altunkilic, Fikret, Blin, Guillaume Alexandre
• Primary Examiner(s): Wells, Kenneth B
• Application Number:
  US14/611,131
• Publication Number:
  US 20150147981A1
• Time in Patent Office: 872 Days
• Field of Search: 327434, 327436, 327437, 333103
• CPC Class Codes: H01L 21/77 Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate electrically programmable read-only memories or multistep manufacturing processes therefor H10B69/00
• CPC Class Codes: H01L 27/1203 the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/162 without feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/687 the devices being field-effect transistors
• 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 2017/066 Maximizing the OFF-resistance instead of minimizing the ON-resistance
• CPC Class Codes: H03K 2217/0009 AC switches, i.e. delivering AC power to a load
• CPC Class Codes: H03K 2217/0018 Special modifications or use of the back gate voltage of a FET
• CPC Class Codes: H03K 2217/0036 Means reducing energy consumption
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

Radio-frequency (RF) switch circuits are disclosed providing improved switching performance. An RF switch system includes at least one field-effect transistor (FET) disposed between a first node and a second node, each having a respective source, drain, gate, and body. The system includes a coupling circuit including a first path and a second path, the first path being between the respective source or the respective drain and the respective gate of the at least one FET, the second path being between the respective source or the respective drain and the respective body of the at least one FET. The coupling circuit may be configured to allow discharge of interface charge from either or both of the coupled gate and body.

Claims

1. A method for operating a radio-frequency switch, the method comprising:

controlling a field-effect transistor disposed between a first node and a second node so that the field-effect transistor is in an ON state or an OFF state, the field-effect transistor having a drain, a source, a body and a gate; and

discharging interface charge from the body of the field-effect transistor through a coupling path connected between the body and the gate, the coupling path being electrically isolated from the drain and the source and including a resistor and a capacitor connected in series, such that the capacitor of the coupling path blocks any and all DC current flow from the gate to the body and from the body to the gate, the resistor being connected directly to the gate at a first end and to the capacitor at a second end.

2. The method of claim 1 wherein the field-effect transistor is a silicon-on-insulator field-effect transistor.

3. The method of claim 1 wherein the capacitor and the resistor are selected to yield a desired intermodulation distortion level of the switch, the desired intermodulation distortion level being below a set threshold.

4. The method of claim 1 wherein a gate bias resistor is connected to the gate.

5. The method of claim 1 wherein a body bias resistor is connected to the body.

6. The method of claim 1 further comprising receiving a radio-frequency signal having a power value at the first node and outputting the radio-frequency signal at the second node when the field-effect transistor is in the ON state.

7. The method of claim 6 wherein the field-effect transistor is connected to N field-effect transistors, the quantity N selected to allow the switch to handle the power value of the radio-frequency signal.

8. A semiconductor die comprising:

a semiconductor substrate;

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

a coupling path connected between the body and the gate, the coupling path being electrically isolated from the drain and the source and including a resistor and a capacitor connected in series, such that the capacitor of the coupling path blocks any and all DC current flow from the gate to the body and from the body to the gate, the resistor being connected directly to the gate at a first end and to the capacitor at a second end.

9. The semiconductor die of claim 8 further comprising an insulator layer disposed between the field-effect transistor and the semiconductor substrate.

10. The semiconductor die of claim 8 wherein the semiconductor die is a silicon-on-insulator die.

11. The semiconductor die of claim 8 wherein the capacitor and the resistor are selected to yield a desired intermodulation distortion level of the semiconductor die, the desired intermodulation distortion level being below a set threshold.

12. The semiconductor die of claim 8 further comprising a gate bias resistor connected to the gate of the field-effect transistor.

13. The semiconductor die of claim 8 further comprising a body bias resistor connected to the body of the field-effect transistor.

14. The semiconductor die of claim 8 wherein the field-effect transistor is connected in series with N field-effect transistors to form a switch circuit, the quantity N selected to allow the switch circuit to handle a power level of an RF signal transmitted by the switch circuit.

15. A wireless device comprising:

a transceiver configured to process RF signals;

an antenna in communication with the transceiver configured to facilitate transmission of an amplified RF signal;

a power amplifier connected to the transceiver and configured to generate the amplified RF signal; and

a switch connected to the antenna and the power amplifier and configured to selectively route the amplified RF signal to the antenna, the switch including a field-effect transistor, the switch further including a coupling path disposed between a body of the field-effect transistor and gate of the field-effect transistor, the coupling path being electrically isolated from a drain of the field-effect transistor and a source of the field-effect transistor and including a resistor and a capacitor connected in series, such that the capacitor of the coupling path blocks any and all DC current flow between the gate and the body, the resistor being connected directly to the gate at a first end and to the capacitor at a second end.

16. The wireless device of claim 15 wherein a gate bias resistor is connected to the gate of the field-effect transistor.

17. The wireless device of claim 15 wherein a body bias resistor is connected to the body of the field-effect transistor.