Output impedance

About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.

A Wideband Low-Power CMOS LNA With Positive–Negative Feedback for Noise, Gain, and Linearity Optimization

Abstract: A wideband common-gate (CG) low-noise amplifier (LNA) utilizing positive-negative-feedback technique is presented. The positive-negative-feedback technique boosts effective transconductance (Gm) and output impedance, which leads to an LNA with higher gain and lower noise figure (NF) over the previously reported amplifiers. In addition, this approach provides high linearity with an aid of third harmonic cancellation, and it breaks transconductance (gm) constriction for input matching in CG amplifiers. In this paper, linearity and output impedance improvement through the proposed technique are fully analyzed. An LNA prototype is implemented in 0.18- μm CMOS technology occupying a total area of 0.33 mm2. The implemented LNA delivers a maximum voltage gain of 21 dB, a minimum NF of 2 dB, an third-order intermodulation intercept point of -3.2 dBm, and 3.6 mW of power consumption in 300-920 MHz of 3-dB bandwidth with input matching (S11 <; -10 dB).

Power amplifier utilizing quadrature hybrid for power dividing, combining and impedance matching

Abstract: A power amplifier includes a quadrature hybrid and input impedance matching network. The power amplifier also includes at least one amplifier that includes an output electrode, and a quadrature hybrid and output impedance matching network. The quadrature hybrid and input impedance matching network exhibits a low pass frequency response.

Fast switching characteristics of a widely tunable laser transmitter

Abstract: We demonstrate a widely tunable laser transmitter that accesses 32 ITU channels with 100-GHz spacing and switches between all channel combinations in less than 45 ns. The compact module uses commercially available electronic components. We investigate the electrical and thermal properties of the laser and the tuning section driver. The experiments show that a low output impedance driver circuit produces faster switching times. Also, temperature variation of the laser limits the wavelength accuracy of the switching. Finally, we present the correlation between switching times and the laser tuning currents.

Switching Behavior of a Heterostructure Based on Periodically Doped Graphene Nanoribbon

Abstract: We theoretically propose a switching device that operates at room temperature. The device is an in-plane heterostructure based on a periodically boron-doped (nitrogen-doped) armchair graphene nanoribbon, which has been experimentally fabricated recently. The calculated $I$-$V$ curve shows that for a realistic device with interface width longer than $20$ nm, nonzero electric current occurs only in the region of bias voltage between $\ensuremath{-}0.22$ and $0.28$ V, which is beneficial to low-voltage operation. Furthermore, in this case, the electric current is robust against the change of the potential profile in the interface since the metallic impurity-induced sub-bands with delocalized wave functions contribute to the transmission exclusively. This also suggests the high response speed of the proposed device. We also discuss the temperature dependence, the output impedance, the effect of phonons, and the possible regimes to extend our work, which suggest that our model may have potential room-temperature nanoelectronics applications.

Method for controlling the impedance of a driver circuit

Abstract: A method for controlling the impedance of drivers controls the output impedance of drivers by coupling the drivers to a impedance control circuit. Accordingly, a desired driver output impedance can advantageously be established and maintained over a wide range of variations in operating conditions and manufacturing processes. Thereby shortening the signal settling time and increasing the attainable signaling frequency.