A circuit comprises a Sallen-Key filter, which includes a source follower that implements a unity-gain amplifier; and a programmable-gain amplifier coupled to the Sallen-Key filter. The circuit enables programmable gain via adjustment to a current mirror copying ratio in the programmable-gain amplifier, which decouples the bandwidth of the circuit from its gain settings. The programmable-gain amplifier can comprise a differential voltage-to-current converter, a current mirror pair, and programmable output gain stages. The Sallen-Key filter and at least one branch in the programmable-gain amplifier can comprise transistors arranged in identical circuit configurations.

An apparatus includes an input amplifier stage and a switch that has a first terminal at a virtual ground input of the input amplifier stage.

Methods and circuits for maximizing gain of a voltage follower circuit are provided. The method includes using a NMOS voltage replica generation circuit, a PMOS voltage replica generation circuit, a NPN BJT voltage replica generation circuit, a n-channel JFET voltage replica generation circuit, a P-Channel JFET voltage replica generation circuit and a PNP BJT voltage replica generation circuit. The overall gain for the various transistor families is almost equal to unity.

An input stage of a chip includes a source driver and a sensing and clamping circuit. The source follower is arranged for receiving an AC-coupled signal to generate an output signal at an output terminal. The sensing and clamping circuit is coupled to the source follower, and is arranged for clamping the output terminal of the source follower at a fixed DC voltage.

An apparatus for performing capacitor amplification in an electronic device may include a first resistor and a second resistor that are connected in series and coupled between a set of input terminals of a receiver in the electronic device, a common mode capacitor having a first terminal coupled to a common mode terminal and having a second terminal, and an alternating current (AC)-coupled amplifier that is coupled between the common mode terminal and the second terminal of the common mode capacitor. The first resistor and the second resistor may be arranged for obtaining a common mode voltage at the common mode terminal between the first resistor and the second resistor. In addition, the common mode capacitor may be arranged for reducing a common mode return loss. Additionally, the AC-coupled amplifier may be arranged for performing capacitor amplification for the common mode capacitor.

A voltage-to-current converter includes a first differential pair of transistors, a second differential pair of transistors, and a first resistor. The first differential pair of transistors includes a first transistor and a second transistor. An emitter of the first transistor is directly connected to an emitter of the second transistor. The second differential pair of transistors includes a third transistor and a fourth transistor. An emitter of the third transistor is directly connected to an emitter of the fourth transistor. The first resistor is connected to the emitter of the first transistor, the emitter of the second transistor, the emitter of the third transistor, and the emitter of the fourth transistor.

An apparatus includes an input amplifier stage and a switch that has a first terminal at a virtual ground input of the input amplifier stage.

An input receiver is provided with a pass transistor that is controlled to pass an input signal to an inverter only while a first binary state for the input signal equals a low voltage. The input receiver also includes a source follower transistor configured to pass a threshold-voltage-reduced version of the input signal while the first binary state of the input signal equals a high voltage greater than the low voltage.

A differential MEMS-readout circuit comprises a first input bonding pad, including a first contact pin and a second contact pin. The differential MEMS-readout circuit comprises a second input bonding pad, including a first contact pin and a second contact pin; and a differential-readout amplifier section comprising a first input connected to the first contact pin of the first input bonding pad and a second input connected to the first contact pin of the second bonding pad, wherein the differential-readout amplifier section comprises a first and a second transistor circuit and each of the second contact pins of the first and second input bonding pads is coupled to one of the first and the second transistor circuits or is coupled to one of the first and the second transistor circuits and/or to ground.

In an embodiment, a differential buffer includes: first and second input terminals configured to receive a differential input voltage; first and second output terminals configured to provide a differential output voltage; a differential source follower amplifier having first and second inputs respectively coupled to the first and second input terminals, and first and second outputs respectively coupled to the first and second output terminals; and a differential common source amplifier having first and second inputs respectively coupled to the second and first output terminals via a first pair of capacitors, and first and second outputs respectively coupled to the first and second output terminals.