Imp Inc.

International Microelectronic Products

Douglas L Hiser

Corey D Petersen

Jaime E Kardontchik

Kou-Hung L Loh

Jamie E Kardontchik

A self-cascoding transconductance circuit has cascoding and current sink/source FETs, serially connected with their gates tied together to receive an input voltage, wherein the cascoding FET has a threshold voltage having an absolute value at least 0.1 volts less than that of the current sink/source FET to ensure that the current sink/source FET operates in its saturated region. A CMOS structure implementing the self-cascoding transconductance circuit has two doped threshold adjust regions formed beneath a gate electrode such that the two doped threshold adjust regions respectively effectuate the cascode and current sink/source FETs which then share the gate electrode. A method of forming the CMOS structure includes forming two self-cascoding transconductance circuits electrically connected in parallel such that they share a common drain region between their respective gate electrodes, and each has one source region. By forming the two self-cascoding transconductance circuits in such a fashion, the effect of alignment errors contributed by each of the parallel connected self-cascoding transconductance circuits is cancelled out for the combined circuit.

Method of fabricating a self-cascoding CMOS device

A digitally programmable Bessel filter includes a plurality of serially connected stages or biquads with each biquad including a plurality of programmable operational transconductance amplifiers. The first stage of the filter provides an all pass equal amplitude response. Two stages provide pulse slimming (first and second derivatives of an input pulse), and three stages provides a sixth order Bessel low pass function. The operational transconductance amplifiers are controlled by a fine tuning control signal, and an array of integrating capacitors are selectively controlled by a coarse tuning signal. The fine tuning and coarse tuning signals are generated in a phase locked loop from a reference clock and a reference biquad which receives the reference clock.

Programmable operation transconductance amplifier

Self-cascoding CMOS device

A digitally programmable Bessel filter includes a plurality of serially connected stages or biquads with each biquad including a plurality of programmable operational transconductance amplifiers. The first stage of the filter provides an all pass equal amplitude response. Two stages provide pulse slimming (first and second derivatives of an input pulse), and three stages provides a sixth order Bessel low pass function. The operational transconductance amplifiers are controlled by a fine tuning control signal, and an array of integrating capacitors are selectively controlled by a coarse tuning signal. The fine tuning and coarse tuning signals are generated in a phase locked loop from a reference clock and a reference biquad which receives the reference clock. The phase locked loop includes a phase detector responsive to the reference clock and the reference biquad, whose output is integrated.

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Berkeley, CA, United States of America

Douglas L Hiser