Analog Devices,inc.

Franklin Marshall Murden, Ii

Scott Gregory Bardsley

Peter Derounian

Michael Ray Elliott

Eric John Siragusa

Carl W Moreland

Harvey J Ray

Javier Alejandro Salcedo

Ahmed Mohamed Abdelatty Ali

Srivatsan Parthasarathy

Jonathan Mark Audy

Ralph David Moore, Jr

James C Camp

Joseph Michael Hensley

Peter Delos

Daniel Rey-Losada

Daniel F Kelly

John P Guido

Marvin J Young

Ege Yetis

Bac Binh Luu

Herein disclosed are systems and circuitry for protecting against overdrive and electrostatic discharge. For example, protection circuitry may include field effect transistors to discharge overdrive outside of an operational voltage range of a circuit in some embodiments to prevent damage to the circuit. Further, the protection circuitry may utilize diode features inherent in the field effect transistors to protect against electrostatic discharge in some embodiments. The circuitry may be implemented in radio frequency sampling analog-to-digital converters and can provide for single-ended signal input and/or output for the analog-to-digital converters.

Electrostatic discharge and overdrive protection circuitry

A common mode feedback (CMFB) loop for a differential amplifier sense an output common mode of a differential circuit and provides feedback to the gates of tail current transistors. Many CMFB loops cannot easily adjust the output common mode voltage and the output common mode may vary over process, voltage, and temperature. An improved CMFB circuit adds a control circuit to control backgates of tail current transistor device(s) of the differential circuit such that the output common mode voltage can be made adjustable.

Common mode feedback circuit with backgate control

A cascaded amplifier including a pre-amplifier stage having a pair of first transistors, each of the first transistors having a first gate terminal coupled to a first input voltage, a trans-conductive (gm) amplifier stage having a pair of second transistors, each of the second transistors having a second gate terminal coupled to a drain terminal of one of the first transistors, and an integrator amplifier stage having a pair of third transistors, each of the third transistors having a third gate terminal coupled to a drain node of one of the second transistors, each of the third transistors having their drain terminals coupled to an output voltage.

Three stage amplifier

One embodiment relates to an apparatus configured to cancel charge injected on a node of a differential pair of nodes. A dummy circuit element can inject charge on an inverted node to cancel charge injected on a non-inverted node by a switch when the switch is switched off. In addition, another dummy circuit element can inject charge on the non-inverted node to cancel charge injected on the inverted node by another switch when the other switch is switched off. These dummy circuits elements can be cross-coupled.

Differential charge reduction

An analog-to-digital converter includes a plurality of sequentially cascaded stages, each stage including an amplifier and four copies of a circuit block including a flash and capacitors, in which the four copies of the circuit block operate interleavingly in a respective sample mode, pre-gain mode, gain mode, and reset mode of the circuit block, the copies of the circuit block in the sample mode, pre-gain mode, and reset mode are decoupled from the amplifier, and the copy of the circuit block in the gain mode is coupled to the amplifier to produce an output for a next following stage.

Pipelined analog-to-digital converter

A charge pump system and method that may provide large supply voltages and currents with reduced ripple voltage at reduced ripple frequency. The charge pump system may include an array of charge pumps and a delay pipeline. The array of charge pumps may include a plurality of charge pumps. The delay pipeline may include a plurality of delay elements. The delay elements may respond to a global trigger signal to output a trigger signal to the array of charge pumps. Respective charge pumps may fire in response to the trigger signal.

Phased-array charge pump supply

A circuit for sampling an analog input signal may include a transistor disposed on a substrate and a sampling capacitor coupled to one of the source and the drain of the transistor. The transistor may be disposed on a substrate that is coupled to ground. A source and a drain of the transistor may be disposed in a back gate of the transistor. The analog input may be supplied to one of the source and the drain of the transistor, and the back gate may receive a back gate voltage having a value that is lower than ground.

CMOS transistor linearization method

Aspects of the present invention provide apparatuses and methods to provide significant gain enhancement for a cascode structure for a differential amplifier. The cascode structure of the differential amplifier can include first and second pairs of output transistors. The second pair of output transistors can be configured to approximately cancel modulation effects of the first pair of output transistors induced by changes in a differential output of differential amplifier, thereby resulting in conditions for providing enhanced gain.

Gain enhancement for cascode structure

Apparatus and methods for pipelined analog-to-digital conversion are disclosed. In some embodiments, a pipeline analog-to-digital converter includes a plurality of multiplying digital-to-analog converter (MDAC) stages coupled in cascade. At least one of the MDAC stages includes two or more flash ADCs connected in parallel, operating alternately to generate digital signals from an analog input voltage. In one embodiment, the flash ADCs provide the digital signals in an alternating manner to a capacitor block that receives a delayed analog input voltage. In another embodiment, the at least one MDAC may include two or more capacitor blocks, each of which is associated with a respective one of the flash ADCs, forming two or more sets of a flash ADC and a capacitor block. In yet another embodiment, the at least one MDAC also include three or more capacitor blocks, each of which can be randomly selected for one of the flash ADCs.

Apparatus and method for pipelined analog to digital conversion

Apparatus and methods for pipelined analog-to-digital conversion are disclosed. In some embodiments, a pipelined analog-to-digital converter includes a control and correction circuit; and a plurality of MDAC stages. At least one of the MDAC stages includes: an MDAC input to receive an analog input voltage; and a dual latch flash ADC comprising one or more dual latch comparators. At least one of the dual latch comparators includes: a pre-amplifier having an input coupled to the MDAC input, and an output; a demultiplexer having an input coupled to the output of the pre-amplifier, a first output, and a second output; a first latch having an input coupled to the first output of the demultiplexer, wherein the first latch may generate a first digital signal; and a second latch having an input coupled to the second output of the demultiplexer, wherein the second latch may generate a second digital signal.

Operational amplifier embodiments are provided to enhance amplifier parameters such as bandwidth, stability, and headroom. In an amplifier embodiment, transistor followers are arranged with first and second differential pairs to facilitate selective positioning of first and second transfer function poles to enhance bandwidth and resistors and inductors are arranged to facilitate selective positioning of complex third transfer function poles to enhance phase margin. In another amplifier embodiment, the transistor followers are arranged to reduce headroom limitations to thereby enhance the voltage swing of output signals.

Operational amplifiers with enhanced parameters

Signal converter systems are provided which reduce degradation of system bit error rate that is caused by metastable conversion errors which generally occur when analog input signals are near reference thresholds Vof system comparators. When operating correctly, the comparators generate a corresponding converter code when the input signals cross the threshold. Metastability, however, may cause the comparators to fail to generate the corresponding converter code. In system embodiments, logic is provided to sense the absence of comparator decisions at the end of a predetermined decision period. In response to this absence, the system is configured to substitute the corresponding converter code. In another embodiment, the system is configured to substitute the corresponding converter code when it lies outside a predetermined digital code window.

Metastability error reduction in signal converter systems

Amplifier embodiments are provided that are well suited for systems which require high signal gains and high transient currents that can drive various loads (e.g., capacitive loads). At least one amplifier embodiment is realized with a cascoded complementary differential input stage, a complementary differential output stage, and a bias controller. The output stage includes lower and upper differential pairs of transistors that respectively have lower and upper coupled back gates and the bias controller is configured to provide bias voltages for the lower and upper coupled back gates.

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Roan Mountain, TN, United States of America

Franklin Marshall Murden, Ii