A low distortion transconductance amplifier provides current to a grounded load using a virtual ground input stage, a pair of current mirrors, and a bias current source. The virtual ground input stage may include transistors arranged as a Darlington pair. The low distortion transconductance amplifier can function as a voltage-controlled AC current source that is operable at high frequencies.

A circuit for receiving an input signal is described. The receiver comprises a first receiver input configured to receive a first input of a differential input signal; a second receiver input configured to receive a second input of a differential input signal; a differential pair having an inverting input and a non-inverting input; a first impedance matching element coupled to the differential pair, wherein the first impedance matching element provides DC impedance matching from the inverting input and non-inverting input of the differential pair; and a second impedance matching element coupled to the differential pair, wherein the second impedance matching element provides AC impedance matching from the inverting input and non-inverting input of the differential pair.

A system for a differential trans-impedance amplifier circuit comprising: an amplifier having a pair of input nodes and configured to generate an amplified replica of a differential voltage on said pair of input nodes; a photodiode; a pair of DC-blocking capacitors coupling said photodiode to said pair of input nodes; at least one resistance coupled between said pair of input nodes of said amplifier; and a bias network comprising two identical photodiode biasing resistances each photodiode biasing resistance coupled in series between said photodiode and a respective DC voltage. A feedback loop for the amplifier may include source followers that are operable to level shift voltages prior to coupling capacitors that couple said photodiode to said amplifier to ensure stable bias conditions for said amplifier. The source followers may include CMOS transistors. The amplifier may be integrated in a complementary metal-oxide semiconductor (CMOS) chip, which may include a CMOS photonics chip.

A semiconductor device includes a low power fast differential transconductor, which provides an output current as a function of a difference between a reference potential input and a feedback potential input. The transconductance increases as an absolute value of the difference between the reference potential and the feedback potential increases. The transconductor includes a reference input stage to receive the reference potential and a reference load coupled in series with the reference input stage. The transconductor includes a feedback input stage to receive the feedback potential and a feedback load coupled in series with the feedback input stage. The transconductor further includes a current limiting component that is configured to control a total current through the reference input stage and the feedback input stage. The transconductor includes a negative feedback path from the reference load to the current limiting component, that compensates for changes in the total current due to differences between the reference potential and the feedback potential.

A wide dynamic range trans-impedance amplifier includes a first trans-impedance amplifier configured to receive a first input current and produce a first voltage as a function of the first input current, and a second trans-impedance amplifier configured to receive a second input current and produce a second voltage as a function of the second input current. A current steering element causes a first portion of current from a current source to flow to the first trans-impedance amplifier until the first current portion reaches the first threshold current, and causes a second portion of current from the current source to flow to the second trans-impedance amplifier, until the second current portion reaches the second threshold current. The second current portion is current from the current source that exceeds the first threshold current. The wide dynamic range trans-impedance amplifier may receive, for example, ion collector current from a hot cathode ionization gauge (HCIG).

The present disclose generally relates to a multichannel low-noise amplifier. At each input to the multichannel low-noise amplifiers, a plurality of transistors can be connected in parallel. This parallel connection decreases the voltage noise beyond what is possible using a single input transistor at each input. As an additional benefit, the initial operating region of the input transistors is not changed. The multichannel low-noise amplifier can be incorporated on a single integrated circuit chip to amplify biological signals to facilitate selective recording of a property (e.g., amplifying neural signals to facilitate selective recording of neural activity).

A tunable matching circuit for use with ultra-low power RF receivers is described to support a variety of RF communication bands. A switched-capacitor array and a switched-resistor array are used to adjust the input impedance presented by the operating characteristics of transistors in an ultra-low-power mode. An RF sensor may be used to monitor performance of the tunable matching circuit and thereby determine optimal setting of the digital control word that drives the switched-capacitor array and switched-resistor array. An effective match over a significant bandwidth is achievable. The optimal matching configuration may be updated at any time to adjust to changing operating conditions. Memory may be used to store the optimal matching configurations of the switched capacitor array and switched resistor array.

Certain aspects of the present disclosure provide methods and apparatus for implementing an amplification system. The amplification system includes an amplifier comprising differential inputs and an output. The differential inputs include an inverting input and a non-inverting input. The amplification system further includes a feedback path from the output coupled to the inverting input. The feedback path from the output is coupled to at least one of an inverting amplifier or buffer, and the at least one of the inverting amplifier or buffer is further coupled to the non-inverting input.

Techniques and mechanisms for providing signal communication with a configurable transceiver circuit. In an embodiment, an integrated circuit comprises transceiver circuitry including an output stage and current mirror circuitry. The output stage is coupled to receive a differential signal pair and to provide at least one output signal based on the differential signal pair. In another embodiment, configuration logic is operable to select between a first mode and a second mode of the transceiver circuit. The first mode includes the current mirror circuitry being disabled from providing a current signal to the output stage, and a first circuit path being closed to provide voltage to the output stage. The second mode includes the first circuit path being open and the current mirror circuitry being enabled to provide a current signal to the output stage.

In an embodiment, an electronic device includes a first amplifier having a non-inverting input configured to receive a reference voltage and an inverting input coupled to a first output node, where the first amplifier is configured to produce a first output voltage at the first output node. The electronic device also includes a second amplifier having a non-inverting input coupled to a ground reference level, and an inverting input coupled to the first output node via a first resistor and to a second output node via a second resistor, where the second amplifier is configured to produce a second output voltage at the second output node.