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 circuit couples 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 I0*m/n through that input transistor, where m is the number of enabled output ports and n is the number of enabled input ports.

An amplifier operates to provide a high output impedance at an output through a push stage having a first transistor of a first transistor type and a pull stage having a second transistor of a second transistor type that is different from the first transistor type. The first transistor and the second transistor are coupled in a common-gate configuration. The first transistor and the second transistor are shorted together via a capacitor coupled to an input and share a common current path as a push-pull current-reusing common-gate low noise amplifier with a broadband input matching.

The present description concerns an amplifier. A first transistor couples a first input node to a first output node. A second transistor couples a second input node to a second output node. The control terminals of the first and second transistors are connected. A third transistor has a control terminal connected to the first input node and a conduction terminal connected to the second output node. A fourth transistor has a control terminal connected to the second input node and a conduction terminal connected to the first output node. A circuit controls a current through the first and second transistors. A circuit delivers a control signal to the control terminals of the first and second transistors.

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.