# US 10,320,379 B2 · Transistor-based radio frequency (RF) switch

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- Number: US 10,320,379 B2
- Document ID: US10320379B2
- Status: Granted
- Kind: B2
- Application number: 15/849,074
- Filed: 2017-12-20
- Published: 2018-06-21
- Granted: 2019-06-11
- Earliest claimed: 2016-12-21
- Assignees: Qorvo US, Inc.
- Applicants: Qorvo US, Inc.
- Inventors: Daniel Charles Kerr; Jinsung Choi; Baker Scott; George Maxim; Hideya Oshima
- Web page: https://patentgrep.com/patent/US10320379B2

## CPC

- H03K 17/161: {in field-effect transistor switches}
- H03K 17/102: {in field-effect transistor switches}
- H03K 17/162: {without feedback from the output circuit to the control circuit}
- 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)
- H04B 1/44: Transmit/receive switching
- H03K 2217/0018: Special modifications or use of the back gate voltage of a FET
- H03K 2217/0054: Gating switches, e.g. pass gates
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- H04B: TRANSMISSION

## Abstract

Disclosed is a transistor-based switch having an N number of main field-effect transistors (FETs) stacked in series such that a first terminal of a first main FET of the N number of main FETs is coupled to a first end node and a second terminal of an Nth main FET of the N number of main FETs is coupled to a second end node, wherein N is a finite number greater than five. The transistor-based switch further includes a gate bias network having a plurality of gate resistors, wherein individual ones of the plurality of gate resistors are coupled to gate terminals of the N number of main FETs. A common gate resistor is coupled between a gate control input and a gate control node of the plurality of gate resistors, and a capacitor is coupled between the gate control node and a switch path node of the main FETs.

## Claims

### Claim 1

A transistor-based radio frequency (RF) switch comprising:
an N number of main field-effect transistors (FETs) stacked in series such that a first terminal of a first main FET of the N number of main FETs is coupled to a first end node and a second terminal of an Nth main FET of the N number of main FETs is coupled to a second end node, wherein N is a finite number greater than five;
a gate bias network comprising:
a plurality of gate resistors, wherein individual ones of the plurality of gate resistors are coupled between gate terminals of adjacent ones of the N number of main FETs;
a common gate resistor coupled between a gate control input and a gate control node of the plurality of gate resistors; and
a first capacitor coupled between the gate control node and a switch path node of the N number of main FETs.

### Claim 2 (depends on 1)

The transistor-based RF switch of claim 1 further including a plurality of speed-up FETs, wherein individual ones of the plurality of speedup FETs are coupled across corresponding ones of the plurality of gate resistors such that the plurality of gate resistors are shorted when the plurality of speedup FETs are in an ON state.

### Claim 3 (depends on 2)

The transistor-based RF switch of claim 2 wherein the N number of main FETs are N-type and the plurality of speed-up FETs are P-type.

### Claim 4 (depends on 1)

The transistor-based RF switch of claim 1 wherein the switch path node is located between a first group of the N number of main FETs coupled between the first end node and the switch path node and a second group of the N number of main FETs coupled between the switch path node and the second end node.

### Claim 5 (depends on 4)

The transistor-based RF switch of claim 4 wherein the first group and the second group are made up of an equal number of the N number of main FETs.

### Claim 6 (depends on 5)

The transistor-based RF switch of claim 5 wherein both a nearest one of the plurality of gate resistors to the first end node and a nearest one of the plurality of gate resistors to the second end node have within ±10% of half of a resistance value of each remaining one of the plurality of gate resistors.

### Claim 7 (depends on 1)

The transistor-based RF switch of claim 1 wherein the switch path node is coupled to the first terminal of the first main FET.

### Claim 8 (depends on 7)

The transistor-based RF switch of claim 7 further including a second capacitor coupled between the second terminal of the Nth main FET and one of the gate terminals associated with the Nth main FET through one of the plurality of gate resistors nearest to the second end node.

### Claim 9 (depends on 1)

The transistor-based RF switch of claim 1 further including a second capacitor coupled between the gate control node and a second switch path node, wherein N is an odd number and the middle one of the N number of main FETs is coupled directly between the switch path node and the second switch path node.

### Claim 10 (depends on 1)

The transistor-based RF switch of claim 1 wherein a first group of the N number of main FETs has source terminals that are closer to the first end node and drain terminals that are closer to the second end node and a second group of the N number of main FETs has drain terminals that are closer to the first end node and source terminals that are closer to the second end node, wherein the first group is equal in number to the second group.

### Claim 11 (depends on 10)

The transistor-based RF switch of claim 10 wherein the first group comprises half of the N number of main FETs, wherein N is an even number.

### Claim 12 (depends on 10)

The transistor-based RF switch of claim 10 wherein each of the first group of the N number of main FETs is coupled to an adjacent one of the second group of the N number of main FETs.

### Claim 13 (depends on 1)

The transistor-based RF switch of claim 1 wherein the first capacitor is a metal-insulator-metal type capacitor.

### Claim 14 (depends on 1)

The transistor-based RF switch of claim 1 wherein capacitance of the first capacitor is between 0.1 picofarad and 10 picofarads.

### Claim 15 (depends on 1)

The transistor-based RF switch of claim 1 where resistance of the common gate resistor is between 2 kΩ and 100 kΩ.

### Claim 16 (depends on 15)

The transistor-based RF switch of claim 15 wherein the resistance of each one of the plurality of gate resistors is equal to the resistance of the common gate resistor within ±10%.

### Claim 17 (depends on 1)

The transistor-based RF switch of claim 1 further comprising:
a body bias network having a plurality of body resistors, wherein individual ones of the plurality of body resistors are coupled to body terminals of the N number of main FETs, and a common body resistor is coupled between a body control input and a body control node of the plurality of body resistors; and
a second capacitor coupled between the body control node and the switch path node of the N number of main FETs.

### Claim 18 (depends on 1)

The transistor-based RF switch of claim 1 further including a plurality of source-to-drain resistors wherein individual ones of the plurality of source-to-drain resistors are coupled between drain terminals and source terminals of individual ones of the N number of main FETs.

### Claim 19 (depends on 1)

The transistor-based RF switch of claim 1 wherein the N number of main FETs are of the silicon-on-insulator type.