The OPA643 provides a level of speed and dynamic range previously unattainable in a monolithic op amp. Using a de-compensated voltage feedback architecture with two internal gain stages, the OPA643 achieves exceptionally low harmonic distortion over a wide frequency range. The "classic" differential input provides all the familiar benefits of precision op amps, such as bias current cancellation...

Ultra wideband (UWB) radio communication is capable of a high data rate with low radiated power. A key issue for UWB design is LNA input/output matching over a wide bandwidth: 3 to 5GHz for the lower band and 3 to 10GHz for the entire band. Several UWB LNAs have been proposed in recent years. The UWB CMOS LNA presented in [1] employs a Chebyshev filter for input matching and a source follower f...

This paper describes a method of extending the signal frequency bandwidth while increasing the stability of a CMOS transimpedance amplifier (TIA). The TIA consists of three inverting amplifiers in a series, and a high-pass filter plus a non-inverting amplifier that are connected to the last two inverting amplifiers stated above in parallel. The TIA is fabricated using a 0.35 μm CMOS process and...

ETRI Journal, Volume 29, Number 5, October 2007 ABSTRACT⎯An ultra-wideband low-noise amplifier is proposed with operation up to 8.2 GHz. The amplifier is fabricated with a 0.18-μm CMOS process and adopts a twostage cascode architecture and a simplified Chebyshev filter for high gain, wide band, input-impedance matching, and low noise. The gain of 19.2 dB and minimum noise figure of 3.3 dB are m...

ETRI Journal, Volume 30, Number 1, February 2008 ABSTRACT⎯A highly linear and efficient GaN HEMT Doherty amplifier for wideband code division multiple access (WCDMA) repeaters is presented. For better performance, the adaptive gate bias control of the peaking amplifier using the power tracking circuit and the shunt capacitors is employed. The measured one-carrier WCDMA results show an adjacent ...

The OPA681 sets a new level of performance for broadband current feedback op amps. Operating on a very low 6mA supply current, the OPA681 offers a slew rate and output power normally associated with a much higher supply current. A new output stage architecture delivers a high output current with minimal voltage headroom and crossover distortion. This gives exceptional single-supply operation. U...

The theory, design and experimental results of a wideband 140 GHz, 1 kW pulsed gyro-traveling wave amplifier are presented. The gyro-TWA operates in the HE(0,6) mode of a novel cylindrical confocal waveguide using a gyrating electron beam. The electromagnetic theory, interaction theory, design processes and experimental procedures have been described in detail. The experiment has produced over ...

As discussed in Chapter 1, in an outphasing power amplifier system, the AM of a bandpass waveform is transformed into PM of two signals prior to power amplification, and finally recovered by recombining the two amplified signals. As shown in Figure 1.16, with this approach, two highly efficient nonlinear power amplifiers can be used without distorting the original signal. This is the main advan...