Transmit-receive port for half-duplex transceiver

Abstract

The invention relates to a transmit-receive port for a half-duplex transceiver. A half-duplex transceiver (300) includes an antenna (202), an antenna-side transformer winding (210) coupled to the antenna, and a low noise amplifier (222) coupled to the antenna through the antenna-side transformer winding.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application, and its parent application is an invention patent application with an application date of May 29, 2020, application number 202080039406.4, and invention name “Transmit-receive port for half-duplex transceiver”. Background Art

[0003] Several communication systems, including but not limited to digital wireless communication systems, wired communication systems, and associated applications, utilize half-duplex transceivers for communication purposes. In a typical half-duplex transceiver, data is transmitted and received at different time periods. In some half-duplex transceivers, various wireless transmission protocols (e.g., 802.11b / g WiFi) combine the transmit port and the receive port (the resulting port is a "Tx-Rx port") on the transceiver in order to free up additional pins. The Tx-Rx port is coupled to an antenna, for example, by bonding wire coupling, to transmit and receive wireless signals. During the time period when the transceiver is configured to receive wireless signals, such received signals are transmitted from the antenna to an amplifier (e.g., a low noise amplifier (LNA)) by capacitive coupling on the secondary side of a power amplifier balun. Capacitive coupling is used as part of a matching network between the antenna and the LNA. However, capacitive coupling increases the noise figure (or reduces the signal-to-noise ratio (SNR)) and is sensitive to changes in bonding wire inductance. Summary of the invention

[0004] According to at least one example of the present disclosure, a half-duplex transceiver includes an antenna, an antenna-side transformer winding coupled to the antenna, and a low noise amplifier coupled to the antenna through the antenna-side transformer winding.

[0005] According to another example of the present disclosure, a half-duplex transceiver includes an antenna and an antenna-side transformer winding coupled to the antenna. The half-duplex transceiver is configured to operate in a receive mode, wherein a low noise amplifier is coupled to the antenna through the antenna-side transformer winding.

[0006] According to yet another example of the present disclosure, a method of operating a half-duplex transceiver including an antenna coupled to an antenna-side transformer winding includes operating the half-duplex transceiver in a receive mode by coupling a low noise amplifier to the antenna through the antenna-side transformer winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a detailed description of various embodiments, reference will now be made to the accompanying drawings, in which:

[0008] Figure 1 A block diagram showing an example communication system according to various examples;

[0009] Figure 2 A block diagram showing a half-duplex transceiver including circuit schematic elements according to various examples;

[0010] Figure 3 A circuit schematic diagram showing a half-duplex transceiver according to various examples;

[0011] Figure 4 presents exemplary Smith charts according to various examples;

[0012] Figure 5 exemplary graphs showing noise figure and power loss as a function of frequency according to various examples; and

[0013] Figure 6 A flow chart of a method for operating a half-duplex transceiver according to various examples is shown. DETAILED DESCRIPTION

[0014] In addition to improving noise performance by mitigating the increased noise figure caused by the capacitive coupling between the antenna and the LNA explained above, it is also desirable to reduce the power consumption of the half-duplex wireless transceiver. Examples of the present disclosure solve the above problems by utilizing an inductor as a coupling between the antenna and the LNA. In the example, the inductor is at least part of a matching network that transforms the impedance of the antenna to an optimal source impedance for the LNA.

[0015] The inductor is coupled to the antenna through the secondary or antenna side winding of the power amplifier balun. The inductor is also coupled to the LNA. By replacing the capacitive matching network with an inductive matching network, the noise figure is reduced. For example, and as will be described below with respect to Figure 4 Explaining further, using an inductor as the coupling between the antenna and the LNA results in a source impedance value that intersects a noise circle that is lower than the value available when using a capacitor as the coupling device.

[0016] In some examples, in addition to the inductor coupling the antenna to the LNA, the matching network also includes components that move the source impedance closer to Gmin (e.g., the optimal source impedance). When an inductor is used as the coupling between the antenna and the LNA, the additional components of the matching network can add less additional inductance to approach Gmin than when a capacitor is used as the coupling device. In addition, the losses due to the coupling of the received signal to the amplifier-side winding of the balanced-unbalanced transformer are reduced, which effectively increases the gain of the LNA. Therefore, for similar gain and noise performance, the half-duplex transceiver current consumption is reduced. The half-duplex transceiver is also less sensitive to changes in the bond line inductance because this value is a relatively small percentage of the total inductance of the matching network, including the inductor as the coupling between the antenna and the LNA, which will be explained in further detail below.

[0017] Figure 1 Depicts a block diagram of a communication system 100 in which various examples may be implemented. Figure 1 In this high-level representation of , the communication system 100 is shown as a transceiver that is designed to transmit and receive signals. Examples of the communication system 100 include, but are not limited to, a subscriber station, a wireless device, a cellular phone, a cordless phone, a handheld two-way radio, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless connection capabilities, other processing devices connected to a wireless modem landline telephone system, a mobile computer or media player with communication capabilities, and other communication devices. The communication system 100 includes a transceiver subsystem 102 including a transmitter subsystem 104 and a receiver subsystem 106, and an antenna 110. In the example, the communication system 100 also includes a local oscillator (LO) subsystem 108 that provides an LO signal (or a signal derived from the LO signal) to the transmitter subsystem 104 and the receiver subsystem 106.

[0018] In an example, the transceiver subsystem 102 is a half-duplex transceiver that includes a transmitter subsystem 104 for transmitting data and a receiver subsystem 106 for receiving data. Some components of the transmitter subsystem 104 and the receiver subsystem 106 may be common components. The transmitter subsystem 104 and the receiver subsystem 106 are configured to operate at different time intervals for transmission and reception of data, respectively. For example, during a transmission phase of the transceiver subsystem 102, the transmitter subsystem 104 is in an active state, and the receiver subsystem 106 is in an inactive state. During a reception phase of the transceiver subsystem 102, the receiver subsystem 106 is in an active state, and the transmitter subsystem 104 is in an inactive state.

[0019] Figure 2 A half-duplex transceiver 200 including a transmitter subsystem 104 and a receiver subsystem 106 is shown in further detail, with certain circuit elements depicted. The transmitter subsystem 104 includes a transmitter chain 211 coupled to a power amplifier 212. The power amplifier 212 is configured to generate a differential signal that is applied to an amplifier-side winding 208 of a balun 206. The balun 206 also includes an antenna-side winding 210 coupled to an antenna 202. When the power amplifier 212 applies the differential signal to the amplifier-side winding 208, the balun 206 operates to convert the differential signal to a single-ended signal in the antenna-side winding 210, which is then transmitted via the antenna 202.

[0020] The receiver subsystem 106 includes a receiver chain 223 coupled to a low noise amplifier (LNA) 222. Examples of the present disclosure do not limit the LNA 222 to any particular topology or design; rather, the LNA 222 may include various known topologies, such as Figure 3 The common gate or common source with source degeneration is shown in FIG. Figure 2 2 and matching network 216 to illustrate the distinction between amplification functionality (e.g., performed by LNA 222) and impedance matching functionality (e.g., performed by matching network 216). However, it should be understood that certain components (e.g., components such as transistors and inductors, which are described below with respect to FIG. 1 ) are not necessarily identical. Figure 3 222 and the impedance matching functionality of the matching network 216. Figure 2 2 and matching network 216 are shown separately in FIG. 2 , but the subcomponents of these functional blocks are not necessarily mutually exclusive or distinct.

[0021] The matching network 216 is in turn coupled to the antenna side winding 210. The transmit-receive switch (Tx-Rx switch) 214 is configured to selectively couple a node 215 between the antenna side winding 210 and the matching network 216 to a ground node. In this example, the Tx-Rx switch 214 is an n-type metal-oxide-semiconductor field effect transistor (MOSFET). Thus, in the example, when a signal (EN) applied to the gate of the Tx-Rx switch 214 is asserted, the Tx-Rx switch 214 is turned on and couples the node 215 to the ground node. Conversely, when the EN signal is deasserted, the Tx-Rx switch 214 is not turned on and isolates the node 215 from the ground node.

[0022] As explained above, various wireless transmission protocols (e.g., 802.11b / g WiFi) combine the transmit port and the receive port (the resulting port is a "Tx-Rx port") on a transceiver in order to free up extra pins. Figure 2 In the example of , antenna 202 is coupled to this single Tx-Rx port 203. Examples of the present disclosure may be applied to any half-duplex system.

[0023] The transmitter subsystem 104 is active during the time period in which the half-duplex transceiver 200 is transmitting. To enable transmission of signals through the antenna 202, the transmitter chain 211 includes suitable logic, circuitry, and / or executable instructions to enable generation of an RF transmit signal. The generated RF transmit signal from the transmitter chain 211 is coupled to the input of the power amplifier 212. The power amplifier 212 contains suitable logic, circuitry, and / or executable instructions to amplify the signal at its input. In an example, the RF transmit signal is transmitted by the antenna 202 at a higher power level than the RF signal received at the antenna 202, and thus the power amplifier 212 receives the RF transmit signal as input, amplifies the RF transmit signal, and provides the amplified RF transmit signal to the amplifier side winding 208 of the balun 206. The amplifier side winding 208 transfers electrical energy to the antenna side winding 210 (e.g., by magnetic coupling), which in turn provides a signal to the antenna 202 for wireless transmission.

[0024] During the time period when the half-duplex transceiver 200 is transmitting, the EN signal is asserted, and thus the Tx-Rx switch 214 is turned on and couples the node 215 to the ground node. The amplitude of the amplified RF transmit signal is large, which may, for example, damage the LNA 222. To avoid such damage, the Tx-Rx switch 214 fully decouples the antenna side winding 210 from the matching network 216 and thus the LNA by providing a connection from the antenna side winding 210 to the ground node.

[0025] During the time period in which the half-duplex transmitter 200 is receiving, the EN signal is de-asserted, and thus the Tx-Rx switch 214 is non-conductive and isolates the node 215 from the ground node. Therefore, the antenna side winding 210 is coupled to the matching network 216, and in turn coupled to the LNA 222. Therefore, the antenna side winding 210 acts as an inductive signal coupling because the antenna 202 is coupled to the LNA 222 through the antenna side winding 210. The RF signal is received at the antenna 202 and transmitted to the LNA 222 through the antenna side winding 210 and the matching network 216. The LNA 222 amplifies the received RF signal and provides the amplified received RF signal to the receiver chain 223 at the output of the LNA 222. The receiver chain 223 includes suitable logic, circuitry, and / or executable instructions to enable processing of the received RF signal.

[0026] The matching network 216 is configured to pass the received RF signal from the antenna 202 to the LNA 222 while transforming the impedance of the antenna 202 to the optimal source impedance of the LNA 222. It is desirable to design the matching network 216 so as to reduce the noise factor and current consumption of the receiver subsystem 106. It is further desirable to reduce sensitivity to variations in bond line inductance. These factors will be discussed below with respect to Figure 3Further detailed discussion is given.

[0027] Figure 3 An example circuit diagram of a half-duplex transceiver 300 is shown. Figure 2 Similar to the half-duplex transceiver 200, the half-duplex transceiver 300 also includes a transmitter subsystem 104 and a receiver subsystem 106. Figure 3 In, with about Figure 2 Like numbered elements described function in a similar manner, including transmitter chain 211 , power amplifier 212 , balun 206 (and its windings 208 , 210 ), antenna 202 , Tx-Rx port 203 , Tx-Rx switch 214 , LNA 222 , and receiver chain 223 .

[0028] The half-duplex transceiver 300 further demonstrates the presence of bonding wire inductance, represented by an inductor 304 coupled to the antenna 202 and the antenna side winding 210 of the balun 206. A bias voltage source 318 and a bias resistor 320 are coupled to the input of the LNA 222 and are configured to provide a direct current (DC) voltage at the input of the LNA 222 to allow for proper amplification of the received RF signal. In this example, the LNA 222 includes a first n-type MOSFET 322 and a second n-type MOSFET 323, each having a gate, a source, and a drain. The source of the first n-type MOSFET 322 is coupled to a source degeneration inductor 324, which in turn is coupled to a ground node. The gate of the first n-type MOSFET 322 is coupled to a gate inductor 321 and serves as the input of the LNA 222, while the drain of the first n-type MOSFET 322 is coupled to the source of the second n-type MOSFET 323. The gate of the second n-type MOSFET 323 is coupled to a voltage source, which is not shown for simplicity but provides a voltage V b 323 to bias the gate of the second n-type MOSFET 323. The drain of the second n-type MOSFET 323 is coupled to the receiver chain 223 and provides the amplified received RF signal to the receiver chain 223 for additional processing. The drain of the second n-type MOSFET 323 is also coupled to the load inductor 325, which is in turn coupled to the supply voltage node, which in this example is V DD As mentioned above, Figure 2 As explained, the components of LNA 222 may also contribute to the impedance matching functionality of the receiver subsystem 106. For example, gate inductor 321 and source degeneration inductor 324 provide impedance matching functionality in addition to being part of the LNA 222 topology. Similarly, n-type MOSFETs 322, 323 provide impedance matching functionality in addition to being part of the LNA 222 topology.

[0029] The first n-type MOSFET 322 provides a current proportional to its transconductance and the quality factor of the matching network 216, which in this example is represented by the gate inductor 321 and the source degeneration inductor 324. This amplified current flows through the second n-type MOSFET 323 and into the load inductor 325, resulting in a voltage gain at Vout relative to the signal voltage at the gate of the n-type MOSFET 322, which is received and processed by the receiver chain 223. Therefore, the gain of the LNA 222 is affected by the quality factors of the matching network 216 (e.g., the gate inductor 321 and the source degeneration inductor 324) and the load inductor 325, as well as the transconductance of the n-type MOSFET 322. As explained above, the gain of the LNA 222 is also improved because the inductance that needs to be provided by the matching network 216 to achieve Gmin is lower when using the antenna side winding 210 acting as an inductor as a signal coupling element than when using a capacitive coupling element.

[0030] According to an example, signal coupling from antenna 202 to LNA 222 is provided by antenna side winding 210 acting as an inductor. Specifically, antenna side winding 210 is coupled to the input of LNA 222 (e.g., coupled to the gate of first n-type MOSFET 322 through gate inductor 321) and to antenna 202.

[0031] As explained above, a bond wire may be used to couple the antenna 202 to the antenna side winding 210 of the balun 206. This bond wire coupling has its own inductive component 304, which may vary with process tolerances, thereby affecting the noise performance of the receiver subsystem 106. However, the sum of the antenna side winding 210 and the gate inductor 321 is much larger than the bond wire inductor 304. Therefore, by using the antenna side winding 210 as the signal coupling from the antenna 202 to the input of the LNA 222, the effect of variations in the bond wire inductance 304 on the noise performance of the receiver subsystem 106 is reduced. In one example, the antenna side winding 210 and the inductor 316 may have an inductance of approximately 4nH, while the bond wire inductance 304 is approximately 1nH and varies up to + / -10% (0.1nH) based on the frequency of the received RF signal. Thus, the total inductance in the signal path from antenna 202 to LNA 222 varies from approximately 4.9 to 5.1 nH, which is only a 2% variation. Since the impact of variations in bond line inductance 304 is reduced, the overall noise performance of receiver subsystem 106 is improved over the range of variations in bond line inductance 304.

[0032] In addition to reducing performance dependence on variations in bond line inductance 304, using inductor 321 as a signal coupling from antenna side winding 210 to the input of LNA 222 also improves the noise figure of LNA 222 and the current consumption of receiver subsystem 106, as shown in FIG. Figure 4 and 5 Further explanation. Figure 4 A Smith chart 400 is shown with noise figure circles 402, 404, 406, 408 corresponding to the noise figure of LNA 222 of 2, 2.5, 3, and 3.5 dB, respectively. The Smith chart 400 includes an impedance curve 410 that varies with frequency (e.g., 2.3 to 2.5 GHz), which corresponds to "Gmin" for LNA 222. The Smith chart 400 also includes an impedance curve 412 that varies with frequency, which corresponds to utilizing the antenna side winding 210 as the signal coupling between the antenna 202 and the input of the LNA 222. Finally, the Smith chart 400 includes an impedance curve 414 that varies with frequency, which corresponds to utilizing a capacitor as the signal coupling between the antenna 202 and the input of the LNA 222.

[0033] As can be seen, in terms of noise figure, the impedance curve 412 corresponding to the antenna side winding 210 acting as an inductive signal coupling is about 1 dB better than the impedance curve 414 corresponding to the capacitive signal coupling. In addition, the impedance curve farther from the noise figure circle 402 (which represents the optimal source impedance for the LNA 222) requires more inductance to rotate the impedance curve into the noise figure circle 402. In an example, increasing the inductance in the matching network introduces additional noise to the RF signal propagating through the matching network. Therefore, to achieve the optimal source impedance for the LNA 222, the matching network using capacitive signal coupling requires more inductance and introduces more noise than the matching network using the inductive signal coupling of the antenna side winding 210.

[0034] In addition to the improved noise performance achieved by using the inductive signal coupling of the antenna side winding 210 between the antenna 202 and the input of the LNA 222, the current consumption of the receiver subsystem 106 is also reduced. Figure 5A set of waveforms 500 are shown demonstrating frequency varying noise factor and power loss caused by using capacitive signal coupling and using capacitive signal coupling of the antenna side winding 210. The waveforms 500 include a waveform 502 showing the frequency varying noise factor when using capacitive signal coupling and a waveform 504 showing the frequency varying noise factor for inductive signal coupling (e.g., inductive signal coupling of the antenna side winding 210 as explained above). The waveforms 500 also include a waveform 506 showing the frequency varying power loss due to the received signal coupling to the amplifier side winding 210 of the balun 206 for the inductive signal coupling (e.g., inductive signal coupling of the antenna side winding 210 as explained above). The waveforms 500 further include a waveform 508 showing the frequency varying power loss due to the received signal coupling to the amplifier side winding 210 of the balun 206 for the capacitive signal coupling.

[0035] As in Figure 5 504, the power loss of the inductive signal coupling shown by waveform 506 is less than the power loss of the capacitive signal coupling shown by waveform 508 for approximately equivalent noise figure performance at 2.4 GHz (e.g., the intersection of waveforms 502 and 504). Due to the improved noise performance provided by the inductive signal coupling, as shown in FIG. Figure 4 As demonstrated in and explained above, LNA 222 current consumption (and therefore half-duplex transceiver 300 current consumption) is reduced while still providing noise performance comparable to a half-duplex transceiver using capacitive signal coupling.

[0036] Figure 6A method 600 for operating a half-duplex transceiver, such as the half-duplex transceiver 300 described above, is shown. The half-duplex transceiver 300 includes an antenna 202 coupled to an antenna-side transformer winding 210. The method 600 begins in block 602, where the half-duplex transceiver 300 is operated in a receive mode by coupling a low noise amplifier (e.g., LNA 222) to the antenna 202 by the antenna-side transformer winding 210. In this manner, inductive signal coupling is provided between the antenna 202 and the LNA 222, which improves the performance of the half-duplex transceiver 300 as explained above. The method 600 optionally continues in block 604, where the half-duplex transceiver 300 is operated in a transmit mode by decoupling the low noise amplifier (e.g., LNA 222) from the antenna-side transformer winding 210. As explained above, the transmit-receive switch 214 may facilitate operation in such transmit and receive modes. For example, during the receive mode, the transmit-receive switch 214 is controlled so as to be non-conductive, thereby coupling the antenna side transformer winding 210 to the LNA 222. During the transmit mode, the transmit-receive switch 214 is controlled so as to be conductive, which couples the node 215 between the antenna side transformer winding 210 and the LNA 222 to the ground node, thereby effectively decoupling the LNA 222 from the antenna side transformer winding 210.

[0037] In the foregoing discussion and in the claims, the terms "include" and "comprises" are used in an open-ended manner and should therefore be interpreted to mean "including (but not limited to) ...". In addition, the term "coupled" is intended to mean an indirect or direct connection. Thus, if a first device is coupled to a second device, the connection may be by a direct connection or by an indirect connection via other devices and connections. Similarly, a device coupled between a first component or location and a second component or location may be by a direct connection or by an indirect connection via other devices and connections. An element or feature "configured to" perform a task or function may be configured (e.g., programmed or structurally designed) at the time of manufacture by the manufacturer to perform the function and / or may be configurable (or reconfigurable) by a user after manufacture to perform the function and / or other additional or alternative functions. The configuration may be programmable by the firmware and / or software of the device, by the construction and / or layout of the hardware components and interconnections of the device, or a combination thereof. In addition, the use of the phrase "ground" or the like in the foregoing discussion is intended to include a backplane ground, a surface ground, a floating ground, a virtual ground, a digital ground, a common ground, and / or any other form of ground connection that is applicable or suitable for the teachings of the present disclosure. Unless otherwise stated, "about," "approximately," or "substantially" preceding a value means + / - 10% of the stated value.

[0038] The above discussion is intended to illustrate the principles and various embodiments of the present disclosure. Once the above disclosure is fully understood, numerous changes and modifications will become apparent to those skilled in the art. It is intended that the appended claims be interpreted as covering all such changes and modifications.

Claims

1. A transceiver, comprising: a transformer having a primary winding and a secondary winding, the secondary winding of the transformer having a first inductance; a first amplifier having an output coupled to the primary winding of the transformer; an antenna coupled to the secondary winding of the transformer without using capacitive coupling, wherein the antenna is coupled to the secondary winding of the transformer via a bonding wire having a second inductance lower than the first inductance; a switch coupled to the secondary winding of the transformer; and A second amplifier having: an input coupled to the secondary winding of the transformer; and A first transistor has a control terminal coupled to the secondary winding of the transformer via an inductor. 2 . The transceiver of claim 1 , wherein the antenna is inductively coupled to the secondary winding of the transformer. 3 . The transceiver of claim 1 , further comprising an inductive matching network coupled between the input of the second amplifier and the secondary winding of the transformer. 4 . The transceiver of claim 1 , wherein the switch is configured to conduct in a transmit mode of the transceiver and to not conduct in a receive mode of the transceiver. 5 . The transceiver of claim 1 , wherein the second amplifier further comprises a degeneration inductor coupled between a current path of the first transistor and a reference terminal. 6 . The transceiver of claim 1 , further comprising a bias voltage source coupled to the control terminal of the first transistor. 7 . The transceiver of claim 6 , further comprising a resistor coupled between the bias voltage source and the control terminal of the first transistor. 8 . The transceiver of claim 6 , wherein the bias voltage source is coupled to the control terminal of the first transistor and to the secondary winding of the transformer without using capacitive coupling.

9. The transceiver of claim 1, wherein the transformer is a balun transformer.

10. The transceiver of claim 1, wherein the second inductance is at least four times lower than the first inductance.

11. The transceiver of claim 1, wherein the transceiver is a half-duplex transceiver, wherein the first amplifier is a power amplifier, and wherein the second amplifier is a low noise amplifier.

12. A transceiver, comprising: a transformer having a primary winding and a secondary winding, the secondary winding of the transformer having a first inductance; a first amplifier having an output coupled to the primary winding of the transformer; an antenna coupled to the secondary winding of the transformer without using capacitive coupling, wherein the antenna is coupled to the secondary winding of the transformer via a bonding wire having a second inductance lower than the first inductance; a switch coupled to the secondary winding of the transformer; and A second amplifier has an input coupled to the secondary winding of the transformer, wherein the secondary winding of the transformer is coupled between the antenna and the switch. 13 . The transceiver of claim 12 , wherein the second amplifier comprises a first transistor having a control terminal coupled to the secondary winding of the transformer via an inductor.

14. An electronic circuit comprising: first and second transformer terminals configured to be coupled to a primary winding of a transformer; third and fourth transformer terminals configured to be coupled to a secondary winding of the transformer; a first amplifier having an output coupled to the first and second transformer terminals; an antenna terminal coupled to the third transformer terminal without using capacitive coupling; a switch coupled between the fourth transformer terminal and a reference terminal; a second amplifier having an input coupled to the fourth transformer terminal; and A bias voltage source has an output coupled to the input of the second amplifier and to the fourth transformer terminal without capacitive coupling.

15. The electronic circuit of claim 14, wherein the antenna terminal is inductively coupled to the third transformer terminal.

16. The electronic circuit of claim 15, wherein the antenna terminal is inductively coupled to the third transformer terminal via a bonding wire.

17. The electronic circuit of claim 14, further comprising an inductive matching network coupled between the input of the second amplifier and the fourth transformer terminal.

18. The electronic circuit of claim 14, wherein the switch is configured to conduct in a transmit mode of the electronic circuit and to not conduct in a receive mode of the electronic circuit.

19. The electronic circuit of claim 14, wherein the second amplifier comprises a first transistor having a control terminal coupled to the fourth transformer terminal via an inductor.

20. The electronic circuit of claim 19, wherein the second amplifier further comprises a degeneration inductor coupled between a current path of the first transistor and the reference terminal.

21. The electronic circuit of claim 19, further comprising a resistor coupled between the output of the bias voltage source and the control terminal of the first transistor.

22. A method comprising: receiving an enable signal via a control terminal of a switch of the transceiver, the switch being coupled between a secondary winding of a transformer and ground, the secondary winding of the transformer being coupled to an antenna without using capacitive coupling and via a bonding wire, the bonding wire having a first inductance at least four times lower than a second inductance of the secondary winding of the transformer, wherein the secondary winding of the transformer is further coupled to an input of a first amplifier, and wherein the transformer includes a primary winding coupled to an output of a second amplifier; providing a bias voltage to an intermediate node coupled to the input of the first amplifier and to the secondary winding of the transformer without capacitive coupling; during a receive mode of the transceiver, deasserting the enable signal to couple the input of the first amplifier to the antenna via the secondary winding of the transformer; and During a transmit mode of the transceiver, the enable signal is asserted to decouple the input of the first amplifier from the antenna.

23. The method of claim 22, wherein providing the bias voltage to the intermediate node comprises providing the bias voltage to the intermediate node via a resistor.

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