A current sensing system constituted of: an impedance element; a switching network arranged to alternately couple a first end of the impedance element between a supply voltage and return, the impedance element arranged to develop a voltage there across reflecting a current flow to a load coupled to the second end of the impedance element; a first stage amplifier, a first and second input thereof respectively coupled to the first and second end of the impedance element, a power supply input thereof coupled to a voltage greater than the supply voltage and a return thereof coupled to the first end of the impedance element, the amplifier having a first and second output, the potential difference reflecting the impedance element voltage times a first stage gain; and a second stage amplifier, a first and second input thereof respectively coupled to a first and second output of the first stage amplifier.

A current sensing system constituted of: an impedance element; a switching network arranged to alternately couple a first end of the impedance element between a supply voltage and return, the impedance element arranged to develop a voltage there across reflecting a current flow to a load coupled to the second end of the impedance element; a first stage amplifier, a first and second input thereof respectively coupled to the first and second end of the impedance element, a power supply input thereof coupled to a voltage greater than the supply voltage and a return thereof coupled to the first end of the impedance element, the amplifier having a first and second output, the potential difference reflecting the impedance element voltage times a first stage gain; and a second stage amplifier, a first and second input thereof respectively coupled to a first and second output of the first stage amplifier.

Apparatus and methods for radio frequency (RF) amplifiers are disclosed herein. In certain implementations, a packaged RF amplifier includes a first bipolar transistor including a base electrically connected to an RF input pin and a collector electrically connected to an RF output pin, and a second bipolar transistor including a base electrically connected to an emitter of the first bipolar transistor and a collector electrically connected to the RF output pin. The packaged RF amplifier further includes a first bias circuit electrically connected between the base of the first bipolar transistor and the RF output pin, a second bias circuit electrically connected between the base of the first bipolar transistor and a power low pin, an inductor implemented at least partly by a bond wire, and a third bias circuit electrically connected in series with the inductor between the base of the second bipolar transistor and the power low pin.

A cell includes a first pair and a second pair of MOS transistors. Each of the first pair and second pair of MOS transistors have drain electrodes coupled to a respective common input node. Each of the first pair and second pair of MOS transistors includes a diode-connected MOS transistor and a latched MOS transistor. The latched MOS transistors of the first pair and second pair of MOS transistors have cross-coupled gate and drain electrodes. Source electrodes of the diode connected MOS transistors from the first pair and second pair of MOS transistors are coupled to a first current output common node to output a current to a first current collecting circuit. Source electrodes of the latched MOS transistors of the first pair and second pair of MOS transistors are coupled to a second current output common node to output a current to a second current collecting circuit.

Aspects of the subject disclosure may include, for example, a common emitter stage having a differential input configured to receive an input signal from an input transmission line, a common base stage coupled with the common emitter stage and having a differential output configured to provide a differential output signal to an output transmission line, and a biasing network to bias the common base stage, the biasing network including components selected to limit common mode gain of the common base stage at relatively high frequencies of interest without affecting a differential mode gain of the common base stage. Other embodiments are disclosed.