An analog-to-digital converter (“ADC”) includes an input terminal configured to receive an analog input voltage signal. A first ADC stage is coupled to the input terminal and is configured to output a first digital value corresponding to the analog input voltage signal and a first analog residue signal corresponding to a difference between the first digital value and the analog input signal. An inverter based residue amplifier is configured to receive the first analog residue signal, amplify the first analog residue signal, and output an amplified residue signal. The amplified residue signal is converted to a second digital value, and the first and second digital values are combined to create a digital output signal corresponding to the analog input voltage signal.

A circuital system that includes a differential low-pass filter having a differential output and operable in a first voltage domain. Some embodiments include a differential integrator including a differential input and a differential output, and operable in a second voltage domain different from the first voltage domain. Some embodiments include a pair of AC coupling capacitors coupling the differential output of the differential low-pass filter to the differential input of the differential integrator.

Described herein is a fully-differential preamplifier comprising an input differential pair, an output current load, and a current source. The current source is coupled between the input differential pair and a low voltage rail and configured to control whether the fully-differential preamplifier is operating in a first mode or a second mode, wherein the preamplifier draws more current when operating in the second mode compared to when operating in the first mode. The input differential pair is coupled between the output current load and the current source. The output current load is coupled between a high voltage rail and the input differential pair. The input differential pair comprise positive and negative inputs of the fully-differential preamplifier. Nodes where the input differential pair and the output current load are coupled to one another comprise positive and negative outputs of the fully-differential preamplifier.

A circuital system that includes a differential low-pass filter having a differential output and operable in a first voltage domain. Some embodiments include a differential integrator including a differential input and a differential output, and operable in a second voltage domain different from the first voltage domain. Some embodiments include a pair of AC coupling capacitors coupling the differential output of the differential low-pass filter to the differential input of the differential integrator.

Provided is a sensor interface including a first cantilever beam bundle including at least one resonator and a first output terminal, a second cantilever beam bundle including at least one resonator and a second output terminal, and a differential amplifier including a first input terminal electrically connected to the first output terminal of the first cantilever beam bundle and a second input terminal electrically connected to the second output terminal of the second cantilever beam bundle.

A programmable transimpedance amplifier (TIA) includes a plurality of signal paths between an output of a common emitter amplifier and the output of the TIA. The TIA is programmed by selecting one of the signal paths, because the paths have different parameters (e.g. different bandwidth). Thus, the bandwidth or other parameter can be programmed by selecting the appropriate path. The common emitter amplifier's output is coupled to the inputs of common base amplifiers in each path. The inputs have low impedance. Also, each path has a separate buffer amplifying the common base amplifier output in the path. Therefore, having multiple paths does not significantly degrade the amplifier performance. High bandwidth can be provided.

A circuit includes an amplifier and a feedback network coupled between the input and the output of the amplifier. The feedback network includes a plurality of parallel coupled branches, each branch having a first selection switch coupled to the input, a second selection switch coupled to the output, and an impedance between the first and second selection switches. Each branch includes a plurality of signal feedback paths coupled in parallel, each having a tuning switch coupled between the first selection switch and the second selection switch of that branch. A control unit is coupled to the feedback network and configured to vary a gain of the amplifier by selectively placing the first and second selection switches of each branch in a conductive state or a non-conductive state and selectively activating respective tuning switches of any branch having first and second selection switches in the conductive state.

The disclosure provides a time gain compensation (TGC) circuit. The TGC circuit includes an impedance network. A differential amplifier is coupled to the impedance network. The differential amplifier includes a first input port, a second input port, a first output port and a second output port. A first feedback resistor is coupled between the first input port and the first output port. A second feedback resistor is coupled between the second input port and the second output port. The impedance network provides a fixed impedance to the differential amplifier when a gain of the TGC circuit is changed from a maximum value to a minimum value.

A common-mode feedback circuit for a fully differential amplifier comprises first (M.sub.B), second (M.sub.TP), and third (M.sub.TN) transistors, each having a respective drain, source, gate, and back-gate terminals. The drain terminal of the first transistor (M.sub.B) and the gate terminals of the first, second, and third transistors (M.sub.B, M.sub.TP, M.sub.TN) are connected together at a bias current terminal. The drain terminals of the second and third transistors are connected together at a tail current terminal. The source terminals of the first, second, and third transistors are connected together. The back-gate terminal of the first transistor (M.sub.B) is arranged to receive a common-mode reference voltage input (V.sub.CM), the back-gate terminal of the second transistor (M.sub.TP) is arranged to receive a positive output voltage (V.sub.P) from the fully differential amplifier, and the back-gate terminal of the third transistor (M.sub.TN) is arranged to receive a negative output voltage (V.sub.N) from the fully differential amplifier.

An active current source load of a fully differential amplifier which is converted into a transconductance (g.sub.m) component also at higher frequency by feed-forwarding input signals to their gates. With signal coupling to gate, unity gain bandwidth (UGB) of the amplifier increases by a factor of two. In addition to this, the signal is coupled to source as well to achieve three-fold UGB enhancement. Thus, the effective trans-conductance is g.sub.mp at dc and becomes g.sub.mp+(g.sub.mn.sub.gate+g.sub.mn.sub.src) at high frequency which triples the UGB when g.sub.mp=g.sub.mn.sub.gate/src.