A novel topology for a HEMT negative current mirror

A new solution for the implementation of a HEMT negative current source is presented. The topology can be also profitably employed as a current mirror and as an active load in high-gain MMICs voltage amplifiers. A small-signal model of the proposed circuit is developed which allows to find accurate expressions for the required transfer functions (i.e., the output impedance of the current source, and the current gain of the circuit when operated as a current mirror). Design examples using Philips PML ED02AH GaAs PHEMT process are provided. Spice simulations show that a 10- kW output impedance for the current source and a 35dB voltage gain for a differential pair loaded with the proposed current mirror are easily achieved

An ultra-low-voltage class-AB OTA exploiting local CMFB and body-to-gate interface

In this work a novel bulk-driven (BD) ultra-low-voltage (ULV) class-AB operational transconductance amplifier (OTA) which exploits local common mode feedback (LCMFB) strategies to enhance performance and robustness against process, voltage and temperature (PVT) variations has been proposed. The amplifier exploits body-to-gate (B2G) interface to increase the slew rate and attain class-AB behaviour, whereas two pseudo-resistors have been employed to increase the common mode rejection ratio (CMRR). The architecture has been extensively tested through Monte Carlo and PVT simulations, results show that the amplifier is very robust in terms of gain-bandwidth-product (GBW), power consumption and slew rate. A wide comparison against state-of-the-art has pointed out that best small-signal figures of merit are attained and good large-signal performance is guaranteed, also when worst-case slew rate is considered

Design Centering and Yield Optimisation of MMIC’s with Off-Chip Digital Controllers

In this paper, a new methodology to perform yield-oriented design of MMIC’s in III-V technologies is proposed. A digital control of MMIC bias, based on process parameters estimation by on-chip auxiliary circuits, allows yield enhancement. The design centering approach and a distance-dependent correlated statistical model of HEMT devices are used to design the external controller. The design of a MMIC for optical digital systems has highlighted significant yield improvement with respect to previously proposed methodologie

CMOS integrated system for terahertz detection

We present the study of a new structure for integrated rectifier, realized with standard CMOS technology, suitable to detect the terahertz radiation, at room temperature. The structure consists of a capacitive rectenna, designed as a patch antenna realized with the last metal layer of the CMOS process. A whisker reaches the gate of a MOS-FET transistor from the antenna, obtained with a standard via. Rectification can be obtained by the self-mixing effect occurring into the plasma waves generate in the substrate, underneath the gate. The proposed solution can be integrated with existing imaging systems, since it does not requires scaling toward very narrow and costly technological node

A bootstrap technique for wideband amplifiers

We propose a novel topology for a wideband amplifier, that exploits a series-shunt positive capacitive feedback to compensate the “polesplitting” action of base–collector capacitance . Feedback is applied to a buffered differential pair to obtain a bootstrap action; the compensation network requires two capacitors and emitter degeneration resistors in the differential pair, and does not affect biasing and low frequency behavior of the amplifier. We present an ac model of the amplifier to get an insight in the behavior of the proposed compensation technique and to obtain design guidelines for maximizing the gain-bandwidth product. A case study using a 27 GHz- Si bipolar technology has shown a 160% gain-bandwidth enhancement with respect to a simple differential pair, and a 27% enhancement with respect to other topologies proposed in the literature