Sharif Digital Repository

A new approach for the design of two-stage Miller-compensated CMOS op amps is presented. The paper studies the basic relations between power consumption, unitygain bandwidth, the biasing region, technology parameters, and the external capacitive load. As a result, simple and efficient design guides are provided to achieve the minimum possible power consumption for the given specifications and for short-channel devices. It is shown that the conventional design procedures do not always result in minimum power op amps. The presented results are also verified by Spectre simulations  

This paper presents a bandwidth enhancement technique for broadband Darlington amplifiers. A detailed analysis of the high-frequency performance of the Darlington amplifier and the effect of bandwidth enhancement is provided. A design procedure is also given for broadband feedback Darlington amplifiers with bandwidth enhancement and gain flattening. A single- and a three-stage feedback amplifier with the proposed improvements are designed and implemented in a 0.25-μm Al-GaAs-InGaAs pHEMT technology. The single-stage amplifier provides 6 ± 0.4 dB of small-signal gain in the frequency band of 1-30 GHz. The three-stage amplifier features 17.8 ± 0.8 dB of small-signal gain in the frequency band... 

New techniques for Class-AB Operational Transconductance Amplifiers (OTAs) are presented. These new techniques are two topologies based on current boosting in class-AB stage which achieve considerable improvement of Slew Rate and Gain-Bandwidth while maintaining the same power consumption as the conventional design. Circuit level analysis and simulation results of proposed circuits in 0.18μm CMOS technology for gain, GBW, slew rate, and settling time are presented to prove the effectiveness of the proposed design method  

A combination of coupled microrings that are coupled to a bus waveguide is proposed as a wide-band microring Raman amplifier. This structure is called one channel coupled microrings (OCCM) Raman amplifier. It is shown analytically that the number of poles in the OCCM transfer function is greater than the square of microrings number (N). The gain bandwidth and gain ripple of the proposed amplifier are increased and decreased, respectively due to increasing the number of poles and zeros in the transfer function. An iterative matrix method is introduced to solve Raman equations in the amplifier with arbitrary number of microrings and Genetic algorithm is employed to maximize the gain flatness  

This paper presents an unilateralization technique for distributed amplifiers (DAs) based on the transformer coupling between the gate and drain lines. Theoretical analysis of the DA indicates that the voltage waves in the gate and drain lines can be described by a system of linear partial differential equations. The transformer coupling between the lines allows for cancellation of the reverse transmission coefficient of the system. There is an optimal value for the coupling coefficient between the lines that unilateralizes the DA. This optimal coupling coefficient is derived in terms of the gate-drain capacitance and capacitances of the gate and drain lines. Using the proposed technique,... 

A novel class AB architecture for single stage multipath differential amplifier is presented. The proposed amplifier combines the flipped voltage follower(FVF) for differential input and the nonlinear current mirror for active load. Applying these techniques to telescopic-cascode amplifier increases the unity-gain bandwidth, the DC gain and the slew rate while the same power consumption as the conventional telescopic cascade is achieved