Techniques for monitoring a distortion signal of a power amplifier circuit, where the output of a distortion monitoring circuit includes little or no fundamental signal and closely represents the actual distortion of the amplifier circuit of a wired communications system. The power amplifier circuit can generate a distortion feedback signal that does not affect the power amplifier's output power capability, e.g., no inherent loss in the fundamental output of the amplifier. That is, using a distortion monitor circuit, the power amplifier circuit can resolve a distortion feedback signal from the intended output signal of the output power amplifier circuit.

The disclosure provides an apparatus including: a pair of signal injection transistors each having a gate terminal coupled to a differential reference signal, and a pair of cross-coupled amplifier transistors configured to amplify a voltage of the differential reference signal to yield a voltage-amplified reference signal at a local oscillator (LO) port of a mixer; an electronic oscillator having an oscillation output node coupled to the LO port of the mixer in parallel with the injection-locked buffer, and configured to generate an oscillator output for transmission to the output node based on a back gate bias voltage applied to the electronic oscillator; and an access transistor having a gate coupled to a switching node, and a back gate terminal coupled to the back gate bias voltage, wherein the access transistor is configured to enable or disable current flow through the electronic oscillator in parallel with the injection-locked buffer.

A MIMO amplifier circuit operable to couple one or more selectable input ports to one or more selectable output ports. The circuit includes N input transistors and M output transistors. Each input transistor has its base coupled to a respective input port node, its emitter coupled to ground, and its collector connected to an intermediate node. Each output transistor has its base coupled to a bias node, its emitter connected to the intermediate node, and its collector coupled to a respective output port nodes. Each input transistor enables the respective input port node when its base is biased. Each output transistor enables the respective output port node when its bias node is asserted. The base of the input transistor for each enabled port is biased to provide a quiescent current I.sub.0*m/n through that input transistor, where m is the number of enabled output ports and n is the number of enabled input ports.

A low noise amplifier (LNA) includes a pair of n-type transistors, each configured to provide a first transconductance; a pair of p-type transistors, each configured to provide a second transconductance; a first pair of coupling capacitors, cross-coupled between the pair of n-type transistors, and configured to provide a first boosting coefficient to the first transconductance; and a second pair of coupling capacitors, cross-coupled between the pair of p-type transistors, and configured to provide a second boosting coefficient to the second transconductance, wherein the LNA is configured to use a boosted effective transconductance based on the first and second boosting coefficients, and the first and second transconductances to amplify an input signal.

An amplifier includes input transconductors that receive an input signal, the input signal having a voltage swing. A supply side current mirror generates a gate voltage as a function of input signal voltage and current sources that provide a bias current of the input transconductors as a function of the gate voltage to maintain a constant bias current across the voltage swing of the input signal. Resistors average source voltages of the transconductance-cancelling transconductors to provide an average source voltage and apply the average source voltage to wells of input devices of the transconductance-cancelling transconductors to reduce back bias effect. The input devices are laid out in a same well and have a common centroid to cancel out process mismatches. A first I-DAC trims an offset of first transconductors, and a second I-DAC trims an offset of second transconductors to attain low offsets across a rail-to-rail input common mode range.

A MIMO amplifier circuit operable to couple one or more selectable input ports to one or more selectable output ports. The circuit includes N input transistors and M output transistors. Each input transistor has its base coupled to a respective input port node, its emitter coupled to ground, and its collector connected to an intermediate node. Each output transistor has its base coupled to a bias node, its emitter connected to the intermediate node, and its collector coupled to a respective output port nodes. Each input transistor enables the respective input port node when its base is biased. Each output transistor enables the respective output port node when its bias node is asserted. The base of the input transistor for each enabled port is biased to provide a quiescent current I.sub.0*m/n through that input transistor, where m is the number of enabled output ports and n is the number of enabled input ports.

A low noise amplifier (LNA) includes a pair of n-type transistors, each configured to provide a first transconductance; a pair of p-type transistors, each configured to provide a second transconductance; a first pair of coupling capacitors, cross-coupled between the pair of n-type transistors, and configured to provide a first boosting coefficient to the first transconductance; and a second pair of coupling capacitors, cross-coupled between the pair of p-type transistors, and configured to provide a second boosting coefficient to the second transconductance, wherein the LNA is configured to use a boosted effective transconductance based on the first and second boosting coefficients, and the first and second transconductances to amplify an input signal.

The disclosure provides an apparatus including: a pair of signal injection transistors each having a gate terminal coupled to a differential reference signal, and a pair of cross-coupled amplifier transistors configured to amplify a voltage of the differential reference signal to yield a voltage-amplified reference signal at a local oscillator (LO) port of a mixer; an electronic oscillator having an oscillation output node coupled to the LO port of the mixer in parallel with the injection-locked buffer, and configured to generate an oscillator output for transmission to the output node based on a back gate bias voltage applied to the electronic oscillator; and an access transistor having a gate coupled to a switching node, and a back gate terminal coupled to the back gate bias voltage, wherein the access transistor is configured to enable or disable current flow through the electronic oscillator in parallel with the injection-locked buffer.

A differential circuit includes a differential pair and a back gate bias circuit. The differential circuit includes a first MOS transistor and a second MOS transistor provided between a first power supply line, to which a first power supply voltage is applied, and a second power supply line, to which a second power supply voltage is applied. The back gate bias circuit applies a bias voltage closer to the first power supply voltage than source potentials of the first MOS transistor and the second MOS transistor to back gates of the first MOS transistor and the second MOS transistor.

For example, an apparatus may include an input to receive an input signal in a first voltage domain; a multi-mode power amplifier switchable between a plurality of power modes to generate an output signal based on the input signal; and an output to provide the output signal. For example, the multi-mode power amplifier may be configured to provide the output signal in the first voltage domain at a first power mode, and to provide the output signal in a second voltage domain at a second power mode. For example, a maximal voltage of the second voltage domain may be at least two times a maximal voltage of the first voltage domain.