Radio-frequency switch having dynamic body coupling
Radio-frequency (RF) switch circuits are disclosed including at least one first field-effect transistor (FET) disposed between first and second nodes, each of the at least one first FET having a respective body and gate. The RF switch circuit may include a coupling circuit that couples the respective body and gate of the at least one first FET, the coupling circuit configured to be switchable between a resistive-coupling mode and a body-floating mode, as well as an adjustable-resistance circuit connected to either or both of the respective gate and body of the at least one FET, the adjustable-resistance circuit including a resistor in parallel with a bypass switch.
1. A radio-frequency switch comprising:
a first field-effect transistor disposed between first and second nodes, the first field-effect transistor having a body and a gate;
a coupling circuit that couples the body and the gate of the first field-effect transistor, the coupling circuit including a second field-effect transistor connected in series with a first resistor; and
an adjustable-resistance circuit connected to the body of the first field-effect transistor, the adjustable-resistance circuit including a second resistor in series with a parallel combination of a third resistor and a bypass switch.
2. The radio-frequency switch of claim 1 wherein the first field-effect transistor is a silicon-on-insulator field-effect transistor.
3. The radio-frequency switch of claim 1 wherein the second field-effect transistor is OFF when the first field-effect transistor is ON to yield a body-floating mode.
4. The radio-frequency switch of claim 3 wherein the second field-effect transistor is ON when the first field-effect transistor is OFF to yield a resistive-coupling mode.
5. The radio-frequency switch of claim 1 further comprising a gate bias resistor connected to a gate of the second field-effect transistor.
6. The radio-frequency switch of claim 1 wherein the first node is configured to receive a radio-frequency signal having a power value and the second node is configured to output the radio-frequency signal when the first field-effect transistor is in an ON state.
7. The radio-frequency switch of claim 6 further comprising N field-effect transistors connected in series with the first field-effect transistor, the quantity N selected to allow the radio-frequency switch to handle the power of the radio-frequency signal.
8. A semiconductor die comprising:
a semiconductor substrate;
a first field-effect transistor formed on the semiconductor substrate;
a coupling circuit that couples a body and a gate of the first field-effect transistor, the coupling circuit including a second field-effect transistor connected in series with a first resistor; and
an adjustable-resistance circuit connected to the body of the first field-effect transistor, the adjustable-resistance circuit including a second resistor in series with a parallel combination of a third resistor and a bypass switch.
9. The die of claim 8 further comprising an insulator layer disposed between the first field-effect transistor and the semiconductor substrate.
10. The die of claim 9 wherein the die is a silicon-on-insulator die.
11. The die of claim 9 wherein the second field-effect transistor is OFF when the first field-effect transistor is ON to yield a body-floating mode.
12. 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 die including a first field-effect transistor;
a coupling circuit that couples a body of the first field-effect transistor and a gate of the first field-effect transistor, the coupling circuit including a second field-effect transistor connected in series with a first resistor; and
an adjustable-resistance circuit connected to the body of the first field-effect transistor, the adjustable-resistance circuit including a second resistor in series with a parallel combination of a third resistor and a bypass switch.
13. The switch module of claim 12 wherein the semiconductor die is a silicon-on-insulator die.
14. The switch module of claim 12 wherein the coupling circuit is part of the same semiconductor die as the first field-effect transistor.
15. The switch module of claim 12 wherein the coupling circuit is part of a second die mounted on the packaging substrate.
16. The switch module of claim 12 wherein the coupling circuit is disposed at a location outside of the semiconductor die.