Abstract: A receive signal strength indicator circuit includes a low-noise amplifier, an envelope detector, and a selection circuit. The low-noise amplifier has a plurality of serially-coupled amplifier stages each providing an amplified signal, wherein a first amplifier stage receives an input signal whose signal strength is to be measured, and a last amplifier stage provides an amplified output signal. The envelope detector stage includes a plurality of envelope detector circuits, each having an input receiving the amplified signal of a corresponding one of the plurality of serially-coupled amplifier stages, and an output for providing a receive signal strength indicator component. The selection circuit is coupled to the outputs of the plurality of envelope detector circuits, and provides the receive signal strength indicator component of one of the plurality of envelope detector circuits having a desired linear range as a detected RSSI signal.

Abstract: A low noise amplifier includes a plurality of serially-coupled amplifier stages. Each serially-coupled amplifier stage provides a respective amplified signal, wherein a first amplifier stage receives an input signal, and a last amplifier stage provides an amplified output signal. Each serially-coupled amplifier stage includes a single-ended amplifier having an input, and an output providing the respective amplified signal, a first passive network, and a second passive network. The first passive network has a first terminal forming an input of a respective one of said plurality of serially-coupled amplifier stages, and a second terminal coupled to said input of said single-ended amplifier, the first passive network including a first capacitor coupled in series between the first and said second terminals of the first passive network. The second passive network is coupled in parallel to the single-ended amplifier and between the input and the output of the single-ended amplifier.

Abstract: A low-noise amplifier includes a low-noise amplifier stage and a filtering and biasing stage. The low-noise amplifier stage receives an input signal and provides a first output signal in response thereto. The low-noise amplifier stage includes a gain element for proving the first output signal, and at least one lowpass filter circuit in series between a first power supply voltage terminal and the gain element having a conductivity determined by lowpass filtering a signal at a bias terminal, and a filtering and biasing stage having an input for receiving the first output signal, and an output for providing a second output signal, and at least one cascode element having a first current conduction path coupled in series between the bias terminal and the output, and having a predetermined filter characteristic.

Abstract: A receive signal strength indicator circuit includes a low-noise amplifier, an envelope detector, and a selection circuit. The low-noise amplifier has a plurality of serially-coupled amplifier stages each providing an amplified signal, wherein a first amplifier stage receives an input signal whose signal strength is to be measured, and a last amplifier stage provides an amplified output signal. The envelope detector stage includes a plurality of envelope detector circuits, each having an input receiving the amplified signal of a corresponding one of the plurality of serially-coupled amplifier stages, and an output for providing a receive signal strength indicator component. The selection circuit is coupled to the outputs of the plurality of envelope detector circuits, and provides the receive signal strength indicator component of one of the plurality of envelope detector circuits having a desired linear range as a detected RSSI signal.

Abstract: One illustrative wearable device embodiment includes: a battery; an antenna coil; a wireless charging module coupled to the antenna coil to harvest wireless power for charging the battery; an NFC (near field communications) module coupled to the antenna coil to receive a query signal and provide a tag response signal; and an NFMI (near field magnetic induction) module coupled to the antenna coil to send and receive audio streams. An illustrative wireless communications method embodiment includes: coupling an antenna coil to a wireless charging module to charge a battery; coupling the antenna coil to an NFC (near field communications) module; and coupling the antenna coil to an NFMI (near field magnetic induction) module to send or receive an audio stream. When coupled, the NFC module receives a query signal, provides a tag response signal, and receives a command signal to set at least one parameter value affecting rendering of the audio stream.

Abstract: One illustrative wearable device embodiment includes: a battery; an antenna coil; a wireless charging module coupled to the antenna coil to harvest wireless power for charging the battery; an NFC (near field communications) module coupled to the antenna coil to receive a query signal and provide a tag response signal; and an NFMI (near field magnetic induction) module coupled to the antenna coil to send and receive audio streams. An illustrative wireless communications method embodiment includes: coupling an antenna coil to a wireless charging module to charge a battery; coupling the antenna coil to an NFC (near field communications) module; and coupling the antenna coil to an NFMI (near field magnetic induction) module to send or receive an audio stream. When coupled, the NFC module receives a query signal, provides a tag response signal, and receives a command signal to set at least one parameter value affecting rendering of the audio stream.