Tag Archives: OPAMP

Simple Acoustic Guitar Sound Receiver

This design of acoustic sound receiver features low power operational amplifier. It has rail-to-rail input/output and 0.85mA supply current per amplifier. It uses piezo speaker as its microphone that can be attached to easily due to its size and dimension.

The circuit is comprised of MCP6L91RT-E/OT 10 MHz, 850 µA operational amplifier that is used to amplify the sound signal. The low-pass filter is used to allow low frequency signal to pass while attenuating high frequency signal or above cut-off frequency of the system to prevent distortions and unnecessary signal. The piezo speaker is used as a microphone or a sound receiver in this circuit. Its size and dimensions is well suited for this application.

The circuit is suitable for different types of acoustic guitar. Since it can be attached easily, the old and other traditional instruments can be developed and modified so that it can continue its service even for the digital era. It can be interfaced to different applications which is not limited to musical instrument.

Simple Acoustic Guitar Sound Receiver – [Link]

LTC6268-10 – 4GHz Ultra-Low Bias Current FET Input Op Amp

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The LTC6268-10 is a single 4GHz FET input op amp for high dynamic range and high speed transimpedance amplifier (TIA) applications. This new decompensated amplifiers extend the speed and dynamic range capabilities of this ultralow bias current op amp family for applications with a gain of 10 or higher. Input bias current is 0.9pA max over the 40°C to 85°C temperature range and just 4pA max over the entire 40°C to 125°C temperature range. Wideband voltage and current noise are 4nV/√Hz and 7fA/√Hz, respectively. With 0.45pF input capacitance and 1000V/μs slew rate, the LTC6268-10 is well suited for photodiode and photomultiplier (PMT) circuits, high impedance sensor applications and for driving analog to digital converters (ADCs). The part is also available as a dual op amp (LTC6269-10) and in unity gain stable options (single LTC6268 and dual LTC6269).

LTC6268-10 – 4GHz Ultra-Low Bias Current FET Input Op Amp – [Link]

 

Dual op amp affords 30-µV precision

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by Susan Nordyk @ edn.com

Supplied in an 8-lead MSOP, the LT6023 dual micropower op amp from Linear Technology provides an input offset voltage of 30 µV maximum and settles to 0.01% in 60 µs, making it useful for multiplexed data-acquisition systems and precision signal processing. Proprietary slew-enhancement circuitry results in a fast, clean output step response with low power consumption.

Specially designed input circuitry maintains high impedance, which minimizes current spikes associated with fast steps for input steps up to 5 V. Slew rate is 1 V/µs, while maximum supply current is 20 µA/amplifier. The LT6023 also includes a shutdown mode that reduces supply current to less than 3 µA when the part is not active. An enable time of 480 µs and a fast slew rate combine to provide power-efficient operation in duty-cycled applications.

Dual op amp affords 30-µV precision – [Link]

OpAmps Tutorial – What is an Operational Amplifier?

The most often requested video! In this tutorial Dave explains what Operational Amplifiers (OpAmps) are and how they work. The concepts of negative feedback, open loop gain, virtual grounds and opamp action. The comparator, the buffer, the inverting and non-inverting amplifiers, the differential amplifier, and the integrator circuit configurations are also explained.
Then a practical breadboard circuit to demonstrate a virtual ground and the effect of voltage rail limitations.

OpAmps Tutorial – What is an Operational Amplifier? – [Link]

App note: Does your op amp oscillate?

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All about Op Amp stability app note from Linear Technology.

Well, it shouldn’t. We analog designers take great pains to make our amplifiers stable when we design them, but there are many situations that cause them to oscillate in the real world. Various types of loads can make them sing. Improperly designed feedback networks can cause instability. Insufficient supply bypassing can offend. Finally, inputs and outputs can oscillate by themselves as one-port systems. This article will address common causes of oscillation and their remedies.

App note: Does your op amp oscillate? – [Link]

New zero-drift Op Amps

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by elektor.com:

Two new low-cost, op amps with close to zero drift operation and low operating quiescent current have been introduced by On Semiconductor. Typical applications include front-end amplifier circuits and power management designs. The NCS325 and NCS333 provide rail-to-rail input and output performance and are optimized for low voltage operation of 1.8 V to 5.5 V. the op amps feature a quiescent operating current of 21 µA and 17 µA respectively at 3.3 V. The devices operate with a gain bandwidth of 350 kHz with ultra-low peak to peak noise down to 1.1 µV from 0.1 Hz to 10 Hz.

New zero-drift Op Amps – [Link]

Visualizing comparator and Op Amp hysteresis

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Kerry Wong writes:

Hysteresis can be added to a comparator circuit to improve its stability, especially when the input signal is noisy. In this post, we will examine the hysteresis characteristics of some common comparator and Op Amps using an oscilloscope.
Perhaps the most intuitive way to visualize the hysteresis in a circuit is to plot the input signal (x axis) against the output signal (y axis). So, if we sweep the input voltage we should be able to see the characteristics of the transitioning of the output voltage due to hysteresis.

Visualizing comparator and Op Amp hysteresis – [Link]

Does your op amp oscillate?

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by Barry Harvey @ edn.com:

We analog designers take great pains to make our amplifiers stable when we design them, but there are many situations that cause them to oscillate in the real world. Various types of loads can make them sing. Improperly designed feedback networks can cause instability. Insufficient supply bypassing can offend. Finally, inputs and outputs can oscillate by themselves as one-port systems. This article will address common causes of oscillation and their remedies.

Does your op amp oscillate? – [Link]

Gamma-photon radiation detector

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An app note on Gamma-photon radiation detector (PDF) by Maxim:

A PIN photodiode, four low-noise op amps and a comparator are used to detect individual photons of gamma radiation. The schematic, design considerations and component selection are discussed.

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Gamma-photon radiation detector – [Link]

Basics of Op Amp Gain Bandwidth Product and Slew Rate Limit

by w2aew @ yoututbe.com

Op amp gain-BW product and slew rate limiting are defined, discussed and demonstrated on the bench. This discussion applies to the majority of general purpose op amps on the market – as most op amps are internally compensated with a single dominant pole. High speed op amps, unconditionally stable op amps, non-unity gain stable op amps, high power opamps, etc. may not follow these characteristics because they are often compensated differently in their design. An LM358N is used for the example circuit. Other popular op amps like the LM741, etc. will behave in a similar way. Sometimes the slew rate limit of a device will be the dominant factor in determining the bandwidth, and other times the gain-bandwidth product will determine the resulting frequency response. The video demonstrates why this happens.

Basics of Op Amp Gain Bandwidth Product and Slew Rate Limit – [Link]