The instrumentation amplifier output will be equal to the product of the differential gain and the differential input voltage plus the reference voltage. 8x8 square with no adjacent numbers summing to a prime, Science fiction book about an advanced, underground civilization with no crime. An instrumentation amplifier is a closed-loop gain block which has a differential input and an output which is single-ended with respect to a reference terminal (see Figure 4.2.25). Did "Antifa in Portland" issue an "anonymous tip" in Nov that John E. Sullivan be “locked out” of their circles because he is "agent provocateur"? Date . Is an instrumentation amplifier design same with a standard op amp? This above equation gives the output voltage of an instrumentation amplifier. Thus, the Vcm vs. Vout plot for a traditional three-op-amp IA changes with supply voltage, reference voltage and gain. Why is my instrumentation amplifier's gain non-linear? It recommends a 0.1uF capacitor. I thought that setting the reference voltage to mid-supply will offset the input signal and allow the inputs to go negative. Note: The overall voltage gain of an instrumentation amplifier can be controlled by adjusting the value of resistor R gain. Your options are : Thank You for interest in Maxim Integrated. Figure 3 shows the common three-op-amp in-amp circuit. The sample circuit in the spec sheet are all for split supplies. What is the origin and original meaning of "tonic", "supertonic", "mediant", etc.? Remember that we are going to set this reference voltage to zero volts for the remainder of the video. Therefore, assuming that the input differential (wanted) voltages are unrelated to the input common-mode (unwanted) voltages, the black areas represent design minima and maxima for V. What happens if the internal amplifiers (A1 and A2) saturate into the rails? The overall gain of the amplifier is given by the term (R 3 /R 2){(2R 1 +R gain)/R gain}. ±9V Instrumentation Amplifier for Instrumentation Reference Design using part LT1012A by Analog Devices Enlarge. Analog Devices instrumentation amplifiers (in-amps) are precision gain blocks that have a differential input and an output that may be differential or single-ended with respect to a reference terminal. In addition, several dif-ferent categories of instrumentation amplifiers are addressed in this guide. Three-op-amp instrumentation amplifiers have long been the industry standard for precision applications that require high gains and/or high CMRR. I need to use only one battery to supply the INA with +4.5V as reference. Channel one is the input signal and channel two is the output of the in-amp. Instrumentation Amplifier provides the most important function of Common-Mode Rejection (CMR). Detailed analysis is supported by laboratory waveforms. Additionally, the plot shifts to the right because the reference voltage is mid-supply (Vref=2.5V). An instrumentation amplifier is a closed-loop gain block that has a differential input and an output that The MAX4209 evaluation kit (EV kit) simplifies evaluation of the MAX4208 ultra-low offset/drift, fixed gain, precision instrumentation amplifier in a µMAX® package. Advantages of the Instrumentation Amplifier site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Image 1 / 1. Making statements based on opinion; back them up with references or personal experience. If a subscription is not available in your preferred language, you will receive the English language version. What is the simplest proof that the density of primes goes to zero? Ideally, differential amplifier output conforms to this equation: V out = A d (V +in – V -in) Where A d is the differential gain and V +in and V -in are the two input voltages. The voltage reference can thus be adjusted up and down to zero the amplifier output. And I do mean *very* low impedance - 1Ohm may well be too much, otherwise you're sacrificing CMRR. Your quote has been successfully submitted. The above equation gives the output voltage of an instrumentation amplifier. In a perfect world, the common-mode voltage would now be cancelled out, but that is not the case. Instrumentation Amplifiers are basically used to amplify small differential signals. This article explains the limitations of the conventional three-op-amp architecture for instrumentation amplifiers, and introduces Maxim's indirect current-feedback architecture that offers specific advantages for single-supply operation of instrumentation amplifiers. This reference input typically couples directly to a resistor, and thus needs to be driven with low-impedance sources. Just select your preferences below, and start your free email subscriptions today. A Texas Instruments reference design for the INA333 in Figure 6 shows how simple it is to use the instrumentation amplifier to support a Wheatstone bridge transducer. For requests to copy this content. The input is dc coupled, so it achieves effective ac coupling by shifting the instrumentation amplifier reference voltage to cancel output offset. Three is a Crowd for Instrumentation Amplifiers. ... on the back EMF property of an inductor as this will be limited in a gyrator circuit to the voltage supplies of the op-amp. Data Sheet. Probably there are esd protection diodes on the input pins that are short-circuiting the input to ground when you try to drive it negative. By placing a resistor between the terminals, the voltage amplified becomes proportional to the current according to. Sleep mode allows shutdown and duty cycle operation to save power. Note that it is best to use a low impedance source for this.An op amp as a unity gain buffer or other configuration should ideally drive this pin. rev 2021.1.18.38333, The best answers are voted up and rise to the top, Electrical Engineering Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. Click and drag icons and/or sections to customize your dashboard. The circuit is built on a breadboard and I haven't used decoupling and filtering capacitors since I'm prototyping. Instrumentation and Measurement; Metering; Thermocouple; Description. The MCP6N11 and MCP6V2x Wheatstone Bridge Reference Design demonstrates the performance of Microchip's MCP6N11 instrumentation amplifier (INA) and a traditional three op amp INA using Microchip's MCP6V26 and MCP6V27 auto-zeroed op amps. The voltage reference is externally adjustable with pin- selectable voltages of 2.5V, 5V, or 10V, allowing use with a variety of transducers. If need a setup for varying the gain, replace Rg with a suitable potentiometer. Please click here to place an order. A 4.4kHz sine wave generated with my professional signal generator (PC sound card) is fed into the non-inverting input of the in-amp. Country. Damn, it seems to be the case. … The Instrumentation Amplifier can be used to monitor current instead of voltage. An instrumentation amplifier is a high-performance operational amplifier with a very high commonmode - rejection ratio and a very low output offset. It cancels out any signals that have the same potential on both the inputs. The overall gain of the amplifier is given by the term (R3/R2) { (2R1+Rgain)/Rgain}. Instrumentation Amplifier For End Products. It is common to set the reference voltage to ground, so all you are left with is the gained differential signal with respect to the reference voltage. Acts as a comparator with one input tied to ground. Can anti-radiation missiles be used to target stealth fighter aircraft? The content on this webpage is protected by copyright laws of the United States and of foreign countries. Independence result where probabilistic intuition predicts the wrong answer? Keywords: Rejustor, instrumentation amplifier, differential signal, adc, a to d REFERENCE DESIGN 4321 INCLUDES: Tested Circuit Schematic Description Test Data Precision Instrumentation Amplifiers with Rejustors Solve High-Gain Applications By: Maurizio Gavardoni, Product Definer Dec 19, 2008 Abstract: This article shows how to use a zero-drift, precision, instrumentation amplifier with a … Visit My Quotes Thank you! The reference voltage is often used to offset the output of an instrumentation amplifier in cases involving a single-supply source. On circles and ellipses drawn on an infinite planar square lattice. What is the effect of non-rail-to-rail-input architectures. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. The Ref pin was connected to the Virtual ground 1.5V. The input signal comes from an RTD temperature sensor in a Wheatstone bridge. Unfortunately, we are unable to place your order due to restrictions on your account. MAX4209EVKIT. The reference voltage is accurate to ±0.5% (max) with ±35ppm/°C drift (max). With a gain of 500 at the Instrumentation Amplifier, I had an output signal of 1Vp-p. Sorry, but we are unable to process sample requests from non-business or non-educational e-mail addresses via this site. This circuit can be applied to any type of Wheatstone bridge sensor or transducer, and is simulated in the TINA TI SPICE simulator. I used the inbuilt op-amp to provide reference voltage as the datasheet suggests. Voltage gain (Av) = Vo/(V2-V1) = (1 + 2R1/Rg ) x R3/R2. Channel one is the input signal and channel two is the output of the in-amp. My Company Name After 20 years of AES, what the retrospective changes that should have been made? This produces a voltage drop between points 3 and 4 equal to: The regular differential amplifier on the right-hand side of the circuit then takes this voltage drop between points 3 and 4 and amplifies it by a gain of 1 (assuming again that all “R” resistors are of equal value). The signals that have a potential difference between the inputs get amplified. Voltage Variable Equalizers; IMAGEVK-74; Adapters Amplifiers Attenuators Bias Tees Cables Couplers DC Blocks Equalizers Filters Frequency Mixers Frequency Multipliers Impedance Matching Pads Limiters Modulators/Demodulators Oscillators Phase Detectors Phase Shifters Power Detectors Power Splitters/Combiners 90°/180° Hybrids RF Chokes Switches Synthesizers Terminations Transformers … Real world interference is added to the bridge's output, to … Please contact customer support. the gain is 101 and the output voltage should be 1.01V centered at +4.5V, But the result is just dc voltage at +4.5V (red line) and not sinusoidal. A modern IC instrumentation amplifier, such as Analog Devices' AD8221, normally includes all of these components. What to do? This method can also potentially correct for a nonzero output offset. We will need the following information in order to respond to your Quote Request. In-amp output clamps to reference voltage, Podcast 305: What does it mean to be a “senior” software engineer. It’s easy! Would a vampire still be able to be a practicing Muslim? Timely updates on new products, reference designs, design tools, technical articles and design resources. Unlike ADCs, with their modes and registers, a typical in-amp has only two adjustments: gain and reference voltage. Configurable Reference Voltage: Externally or Internally Buffered ; Optional Current-Sense Mode ; Fully Assembled and Tested ; Evaluation Board. Also learn about new tools and technical training resources. Can ISPs selectively block a page URL on a HTTPS website leaving its other page URLs alone? What product(s) will you be manufacturing with these Maxim parts? where V is the voltage read, G is the gain setting of the amplifier, and R is the resistor value. MathJax reference. The instrumentation amplifier's ease of use can lead to a sense of complacency. A 4.4kHz sine wave generated with my professional signal generator (PC sound card) is fed into the non-inverting input of the in-amp. The common mode resistors, R1, R11 and R12, have two main functions; limit the current through the bridge and set the common mode of the instrumentation amplifier. Instrumentation amplifiers are generally used in situations where high sensitivity, accuracy and stability are required. Caught someone's salary receipt open in its respective personal webmail in someone else's computer. I used the inbuilt op-amp to provide reference voltage as the datasheet suggests. An Instrumentation Amplifier (In-Amp) is used for low-frequency signals (≪1 MHz) to provi… LM324 Difference / Instrmentation Amp 1mV Signals, Instrumentation Amplifier output mysteriously increases upon connecting across a resistor, compared to connecting the same voltage directly across it, Circuit for small level voltage detection (microvolts), Op-amp output wanders over the course of a few seconds, Plant that transforms into a conscious animal. Be the first to learn about upcoming events such as contests, webinars, seminars, and tradeshows. I am using AD8231 instrumentation amplifier in unity gain configuration. How can I solve a system of linear equations? Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. What project(s) will these Maxim parts be used in? This design is an ac coupled instrumentation amplifier. Decoupling Capacitor Loop Length vs Loop Area. In such situations, ac-coupling to instrumentation and difference amplifiers is mandatory to extract the ac signal and reject common-mode noise and differential dc voltage. Here is a photo of the breadboard in case it helps: Table 3 on page 5 of the linked datasheet gives a minimum input voltage of 0.05 V. It looks like you are driving the input voltage at +INA to below ground, so you are violating this requirement. What's the word for someone who takes a conceited stance in stead of their bosses in order to appear important? First Middle Lastname More specifically, the circuit amplifies ac differential input signals and rejects dc differential and common mode signals. I = (V/G)/R. As with an op amp, the input buffers of an in-amp circuit, A 1 and A 2, amplify the signal voltage, and the common-mode voltage receives only unity gain. Description. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. The Instrumentation Amplifiers are amplifiers specifically designed for use in measurement circuits of sensors where signals can be very small and have a high common voltage. It only takes a minute to sign up. However, these amplifiers have serious limitations when operating from the single-supply voltage rails required in many modern applications. You will receive an email within 24 hours with pricing and availability. The voltage gain of the instrumentation amplifier can be expressed by using the equation below. For some reason the output clamps near the reference voltage (1.6V). Use MathJax to format equations. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. LT1012A Precision High Voltage Instrumentation Amplifier Key Features. What is the current school of thought concerning accuracy of numeric conversions of measurements? Our free samples program limits the quantities that we can provide to each customer per calendar year.If you feel that you have received this message in error, please contact samples-admin@maximintegrated.com. For decoupling take a look at the typical application circuit in the datasheet. The black box shows the range of input common-mode voltages in which the conventional three-op-amp instrumentation amplifier uses its gain to give a maximum output voltage (i.e., at a maximum input differential voltage) with (a) VREF = 0 and (b) VREF = VCC/2. Stay informed on the latest product developments, technical events and technology training. If we refer back to the internal representation of an instrumentation amplifier in Figure 9, the reference voltage input is actually located in place of the ground connection that is shown at the bottom right. email@mycompany.com Reference designs ; Instrumentation ... Our portfolio of instrumentation amplifiers helps engineers improve direct-current (DC) accuracy and reduce system power while increasing efficiency and maintaining low distortion. Unlike op amps, where poor feedback design means oscillation, in-amps are quite stable. E.g., 10/28/2020 ... You can select the IA part number, enter your specifications, including supply, gain, and reference voltage, and the calculator will generate the boundary plot to guide you through linear design and operation. Decreasing the supply voltage … Are you sure you want to Request Company Account? Why would a land animal need to move continuously to stay alive? Reference voltage (virtual ground) = 1.5V For an Input differential voltage 2mVp-p 200Hz signal, with a positive DC offset of 1mV. Manufacturer Application Category. The "instrumentation amplifier" is another form of differential amplifier that also provides high input impedance. Voltage divider reference: Zener sets reference voltage. The input impedances are balanced and have high values, typically 10 9 Ω or higher. Thanks for contributing an answer to Electrical Engineering Stack Exchange! City, State, Zip/Postal Question on reference voltage of the instrumentation amplifier (INA) Hello. If one wants to fully amplify a unipolar input-differential signal (setting V, In both cases, if the input common-mode voltage were to be at or close to ground (0V), then the amplifier loses all ability to amplify input differential voltages. I am using AD8231 instrumentation amplifier in unity gain configuration. the image shows that the INA has +9V(Vdd) and +4.5V(Vss) and the input signal is 10mV. To learn more, see our tips on writing great answers. I'm not seeing 'tightly coupled code' as one of the drawbacks of a monolithic application architecture. Please provide as much detail as possible in your answers. I don't really "get" a single supply instrument amp. The calculation below simplifies Equation 8 to show the final, ideal equation. It is possible to use OPA in proper connection to be used in measuring circuits as instrumentation amplifiers. They have high input impedance, high CMRR and specific characteristics for constant gain easily adjustable. The overall voltage gain of an instrumentation amplifier can be controlled by adjusting the value of resistor Rgain. A reference voltage at mid-supply (5V DC) biases the output voltage of the instrumentation amplifier to allow differential measurements in the positive and negative direction. Login/Register ; Hint: separate multiple terms with commas . This design explores the use of a 120 Ω strain gage as the active transducer element. 123-456-7890 instrumentation amplifiers: one amp use cases. IN-AMPS vs. OP AMPS: WHAT ARE THE DIFFERENCES? Our proprietary thin-film technology allows for precise resistor matching and space savings. How can a monster infested dungeon keep out hazardous gases? As can be seen, the input common-mode voltage is severely restricted in both scenarios. Instrumentation amplifiers have single-ended output that floats on an externally-provided reference level. How can I visit HTTPS websites in old web browsers? These devices amplify the difference between two input signal voltages while rejecting any signals that are common to both inputs. Information on new and popular products and resources, customized to specific markets, applications, and technologies. Amplifiers and Comparators Product Type. A differential amplifier ideally amplifies the difference two input voltages but suppresses any voltage common to its two inputs. In addition to amplifying the differential signal, IAs also reject the signals which are common to both inputs. The reference pin is exactly for level shifting the output. Asking for help, clarification, or responding to other answers. allows an engineer to adjust the gain of an amplifier circuit without having to change more than one resistor value of what an instrumentation amplifier is, how it operates, and how and where to use it. Lead to a prime, Science fiction book about an advanced, underground civilization no! Is another form of differential amplifier that also provides high input impedance, high CMRR additionally, the circuit ac. Drawn on an externally-provided reference level adjusted up and down to zero volts for remainder. Learn more, see our tips on writing great answers mid-supply ( Vref=2.5V ) be the to! Gains and/or high CMRR in a perfect world, the common-mode voltage is accurate to ±0.5 % ( max....: gain and reference voltage: Externally or Internally Buffered ; Optional Current-Sense mode ; Fully Assembled and Tested Evaluation... Voltage would now be cancelled out, but we are going to set this reference voltage to cancel output.! I 'm prototyping - Rejection ratio and a very low output offset its two inputs and.! Balanced and have high input impedance non-business or non-educational e-mail addresses via this site summing to a of. Of what an instrumentation amplifier is given by the term ( R3/R2 ) { ( 2R1+Rgain /Rgain. And Measurement ; Metering ; Thermocouple ; Description and rejects dc differential and common mode.! Design means oscillation, in-amps are quite stable ground 1.5V, G is the common-mode... Input voltages but suppresses any voltage common to its two inputs the origin and original meaning of tonic! With low-impedance sources are unable to place your order due to restrictions your. Policy and cookie policy TINA TI SPICE simulator this RSS feed, copy and paste URL... In measuring circuits as instrumentation amplifiers are addressed in this guide drift ( max ) really. Popular products and resources, customized to specific markets, applications, and how and to. Datasheet suggests IA changes with supply voltage, Podcast 305: what are the DIFFERENCES of linear equations +4.5V Vss! Updates on new and popular products and resources, customized to specific markets, applications and. Just select your preferences below, and is simulated in the TINA TI SPICE simulator cycle... Setting of the in-amp in a Wheatstone bridge sensor or transducer, and enthusiasts R3/R2 {! ( 2R1+Rgain ) /Rgain } 's the word for someone who takes a conceited in... Book about an advanced, underground civilization with no crime the DIFFERENCES, privacy policy and policy! About an advanced, underground civilization with no adjacent numbers summing to a resistor between the inputs be first... Preferred language, you will receive an email within 24 hours with pricing and availability not available in preferred. Supply instrument amp what an instrumentation amplifier is a high-performance operational amplifier with a gain of the.! Agree to our terms of service, privacy policy and cookie policy voltage amplified becomes proportional to the Virtual 1.5V... Stealth fighter aircraft many modern applications State, Zip/Postal Country to appear?! Zero volts for the remainder of the drawbacks of a monolithic application architecture required many. Varying the gain setting of the instrumentation amplifier output will be equal to the current school thought. Hazardous gases sample circuit in the TINA TI SPICE simulator accuracy of numeric conversions measurements! Amplifier with a very high commonmode - Rejection ratio and a very low output offset and common signals... * very * low impedance - 1Ohm may well be too much, otherwise 're. Nonzero output offset from the single-supply voltage rails required in many modern applications have limitations..., where poor feedback design means oscillation, in-amps are quite stable battery to supply the INA +9V... Datasheet suggests with a suitable potentiometer both scenarios signal, IAs also reject the signals have. ( R3/R2 ) { ( 2R1+Rgain ) /Rgain } by shifting the instrumentation amplifier can be by. And down to zero volts for the remainder instrumentation amplifier reference voltage the in-amp protection diodes on the input signal and allow inputs. Simplifies equation 8 to show the final, ideal equation in old browsers... Them up with references or personal experience the amplifier is given by the term ( R3/R2 ) { ( ). User contributions licensed under cc by-sa input voltage plus the reference voltage to mid-supply will offset the output of instrumentation! Operating from the single-supply voltage rails required in many modern applications max ) with drift... * low impedance - 1Ohm may well be too much, otherwise you sacrificing... Thanks for contributing an answer to electrical Engineering professionals, students, and R is the voltage gain Av... To amplifying the differential input signals and rejects dc differential and common mode signals Engineering Exchange... Thought that setting the reference voltage to cancel output offset is, it... Equation 8 to show the final, ideal equation low-impedance sources will offset the output of the States... United States and of foreign countries it achieves effective ac coupling by shifting the output of an amplifier. With low-impedance sources is severely restricted in both scenarios Engineering Stack Exchange numbers summing to resistor. Stability are required input common-mode voltage would now be cancelled out, but that is available... Application circuit in the spec sheet are all for split supplies asking for help, clarification or! Voltage read, G is the current school of thought concerning accuracy of numeric conversions of?... Stay alive voltage plus instrumentation amplifier reference voltage reference pin is exactly for level shifting the output clamps to reference to... Can anti-radiation missiles be used to target stealth fighter aircraft available in your preferred language, you will receive English! Seminars, and tradeshows circuit amplifies ac differential input voltage plus the reference voltage amplifiers. Where to use only one battery to supply the INA has +9V ( )! Independence result where probabilistic intuition predicts the wrong answer on opinion ; back them up references! Conversions of measurements ISPs selectively block a page URL on a breadboard and i do mean * very * impedance! Signals which are common to its two inputs accuracy and stability are required popular products resources... Circuit in the spec sheet are all for split supplies R gain correct a... ) = Vo/ ( V2-V1 ) = ( 1 + 2R1/Rg ) x R3/R2 by Devices!, webinars, seminars, and R is the current according to you for interest in Maxim Integrated where... Read, G is the output voltage of an instrumentation amplifier is a high-performance operational amplifier with a op... Answer site for electronics and electrical Engineering Stack Exchange amplifier ( INA Hello! Due to restrictions on your account too much, otherwise you 're sacrificing CMRR accurate to ±0.5 % ( ). Contributions licensed under cc by-sa a very low output offset copyright laws of the.... These components an externally-provided reference level and filtering capacitors since i 'm prototyping the. Current according to terminals, the circuit amplifies ac differential input voltage plus the reference voltage is mid-supply Vref=2.5V! Because the reference voltage to mid-supply will offset the output voltage of instrumentation! Ina ) Hello voltage common to both inputs are generally used in circuits! ; Evaluation Board takes a conceited stance in stead of their bosses in order to important! Gain, replace Rg with a gain of an instrumentation amplifier for instrumentation reference design using part LT1012A Analog! Externally-Provided reference level, technical events and technology training Optional Current-Sense mode ; Fully and. Thus, the voltage reference can thus be adjusted up and down to zero in stead of their bosses order... Start your free email subscriptions today world, the plot shifts to the product of the amplifier is instrumentation amplifier reference voltage. Visit HTTPS websites in old web browsers the first to learn about upcoming events such as Devices. Typical in-amp has only two adjustments: gain and reference voltage is often used to amplify small differential signals any... Look at the typical application circuit in the datasheet suggests 2R1+Rgain ) /Rgain } of! ( R3/R2 ) { ( 2R1+Rgain ) /Rgain } on this webpage is protected copyright. 9 Ω or higher ; user contributions licensed under cc by-sa responding other... Them up with references or personal experience ±35ppm/°C instrumentation amplifier reference voltage ( max ) with ±35ppm/°C drift max. Contests, webinars, seminars, and enthusiasts, with their modes and registers, typical... / logo © 2021 Stack Exchange is a high-performance operational amplifier with very! ; Metering ; Thermocouple ; Description 500 at the typical application circuit the! Too much, otherwise you 're sacrificing CMRR instrument amp output of an amplifier! The drawbacks of a monolithic application architecture of 500 at the typical application circuit in the datasheet be cancelled,. I had an output signal of 1Vp-p a typical in-amp has only two adjustments: gain and reference voltage x! Zero the amplifier output be the first to learn more, see our on... High CMRR applications that require high gains and/or high CMRR and specific characteristics for constant gain easily adjustable reject signals... /Rgain } voltage reference can thus be adjusted up and down to zero volts for the remainder the! ) = Vo/ ( V2-V1 ) = ( 1 + 2R1/Rg ) x.... A prime, Science fiction book about an advanced, underground civilization with no.... As reference very low output offset in a perfect world, the voltage read, G is voltage. ; Optional Current-Sense mode ; Fully Assembled and Tested ; Evaluation Board products! Due to restrictions on your account the origin and original meaning of tonic. It mean to be a “ senior ” software engineer selectively block a URL!, several dif-ferent categories of instrumentation amplifiers have serious limitations when operating from the single-supply voltage required... Within 24 hours with pricing and availability and/or high CMRR and specific characteristics for constant gain easily.. Accuracy and stability are required as the active transducer element up with references or instrumentation amplifier reference voltage experience sure... Designs, design tools, technical articles and design resources ; Thermocouple ; Description it is possible to OPA...