RAMÍREZ ANGULO , Jaime

A methodology to design currentmode circuits for piecewise-linear function approximation is presented. The technique is based on the utilization of current mirrors as basic building blocks. The resulting circuits are very compact, modular, programmable and can operate at very high frequencies. Experimental results are presented that verify the...

A simple and power efficient approach for the implementation of continuous-time common mode feedback networks using a capacitive averaging network is introduced. It is shown that low voltage, continuous-time, fully differential rail to rail operation can be achieved using the proposed technique. This at the expense of very small additional...

A new high performance second-generation CMOS current conveyor architecture is presented. It is built using a differential flipped voltage follower as its input buffer stage and a cascode current mirror as output stage. It is characterized by very low output impedance. It provides gain independent high bandwidth when used to implement a...

This paper presents the implementation of a crossquad circuit suitable for low-voltage operation. The proposed cell exploits a dynamic positive feedback gm boosting technique to achieve linear voltage-to-current conversion, while it manages to work with low-voltage with no extra bias current and minimal additional hardware. Results for a 0.5 m...

An alternative approach to the design of super class AB recycling folded cascode operational transconductance amplifiers is proposed. Instead of using local common-mode feedback for boosting dynamic currents, simple current mirrors with input transistors entering triode region for large currents are employed. Measurement results from a 0.5 μm...

A novel CMOS tunable transconductor is presented. The circuit operates in classAB hence featuring power efficiency. The internal feedback employed and the use of a linearized triode transistor for voltage-to-current conversion allows achieving high linearity. Rail-to-rail input range is obtained by using floatinggate transistors. Measurement...

A CMOS fully integrated all-pass filter with an extremely low pole frequency of 2 Hz is introduced in this paper. It has 0.08-dB passband ripple and 0.029-mm 2 Si area. It has 0.38-mW power consumption in strong inversion with ±0.6-V power supplies. In subthreshold, it has 0.64-μW quiescent power and operates with ±200-mV dc supplies. Miller...

A 1.5V programmable-gain differential amplifier is implemented using a novel design technique for operating closed-loop amplifier circuits at very low supply voltages. It is based on the use of quasi-floating gate transistors, avoiding issues encountered in true floating-gate structures such as the initial floating-gate charge, offset drift...

A low distortion low-voltage BiCMOS OTA with wide gm adjustment range and constant input range is presented. It is based on a highly linear voltage-to-current converter input stage merged with translinear loops that implement linear electronically programmable current mirrors. Experimental results are provided that confirm the characteristics...

In this paper, a highly power-efficient class-AB–AB Miller op-amp is discussed. The structure uses gm enhancement based on local common-mode feedback to provide class-AB operation with enhanced effective gm , open-loop gain, unity-gain frequency, and slew rate ( SR ) without significant increase in quiescent power consumption. Utilization of a...

The implementation of large-valued floating resistive elements using MOS transistors in subthreshold region is addressed. The application of these elements to bias wideband AC coupled amplifiers is discussed. Simple schemes to generate the gate control voltages for the MOS transistors implementing large resistors so that they remain in high...

The suitability of operational transconductance amplifiers (OTAs) as the main active element to obtain basic building blocks for the design of programmable nonlinear continuous-time networks is examined. The main purpose is to show that the OTA, as the active element in basic building blocks, can be efficiently used for nonlinear...

In this paper a novel transconductor based on floating gate techniques that performs current multiplication for tuning is presented. The multiplication is achieved using transistors operating in weak and moderate inversion together with floating voltage sources implemented conveniently by floating capacitors. Besides, a tuning scheme is...

It is shown that the operational transconductance amplifier, as the active element in basic building blocks, can be efficiently used for programmable nonlinear continuous-time function synthesis. Two efficient nonlinear function synthesis approaches are presented. The first approach is a rational approximation, and the second is a...