We present two cryogenic Application Specific Integrated circuits (ASIC's) realized with a GaAs MESFET process. A single-channel differential or double-channel singleended voltage sensitive preamplifier for 4.2 K operation, to be used with bolometric detectors, was realized and tested. A very simple structure working as a unity gain buffer or as a transconductance amplifier, or even as a shapin...

This article presents a current-mode quadrature oscillator. The proposed oscillator can provide 2 sinusoidal output currents with 90 0 phase difference. It also provides high output impedances that make the circuit able to directly drive load without additional current buffer. The condition of oscillation and frequency of oscillation can be controlled independently and electronically by adjusti...

This paper reports a novel MMIC balanced sub-harmonic cold FET mixer for MVDS applications using 0.15mm GaAs pHEMT. The mixer, which includes a LO buffer amplifier, was optimized for highly linear upconversion performance in the 42-43.5GHz RF band, 19.520.5GHz LO band and 2.45-3.45 GHz IF band. A dedicated simulation method has been developed to optimize conversion loss and determine optimum ma...

In this research contribution, the electronically tunable first-order universal filter employing a single voltage differencing differential input buffered amplifier (VD-DIBA) (constructed from two commercially available integrated circuit (IC): operational transconductance amplifier, IC number LT1228, and buffer, AD830), one capacitor resistors. The features of designed first order are as follo...

We demonstrate the applicability of quantum-dot semiconductor-opticalamplifier based wavelength converters to the implementation of an ultra-high speed optical packet switching buffer. The buffer architecture consists of cascaded programmable delay stages that fully utilize the available wavelengths and thus minimize the number of wavelength converters that are required to implement the buffer....

The operational amplifier is perhaps the most useful integrated device in existence today. It is widely used in analogue computers, simulation systems and in a variety of electronic applications such as filtering, buffering and comparison of signal levels. In this paper, the different schemes of power-efficient class AB two-stage op-amps using a current replication branch and adaptive loads wer...