AD Rev. D. Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for. AD Low Cost Instrumentation Amplifier FEATURES Easy to Use Low Cost Solution Higher Performance than Two or Three Op Amp Design Unity Gain with . FEATURES Easy to use Low cost solution Higher performance than two or three op amp design Unity gain with no external resistor Optional gains with one.
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Low Cost Instrumentation Amplifier AD Data Sheet FEATURES
Documents Flashcards Grammar checker. For a gain of 1, no external resistor is required. The AD is a complete difference or subtractor amplifier system that also provides superior linearity and common-mode rejection by incorporating precision laser-trimmed resistors.
The AD replaces low cost, discrete, two or three op amp instrumentation amplifier designs and offers good commonmode rejection, superior linearity, temperature stability, reliability, power, and board area consumption. The low cost of the AD eliminates the need to design discrete instrumentation amplifiers to meet stringent cost targets. While providing a lower cost solution, it also provides performance and space improvements. E Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice.
No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks datasgeet registered trademarks are the property of their respective owners. One Technology Way, P. BoxNorwood, MAU. A Typical Application Error Budget Universal Added Thermal Resistance Section May be further restricted for gains greater than See the Input Protection section for more information.
Ad6222 above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Voltage Noise Spectral Density vs. Current Noise Spectral Density vs. Change in Input Offset Voltage vs. Warm-Up Time Figure 7. Output Voltage Swing vs. Settling Time to 0. Datzsheet, for a 10 V Step Rev. Settling Time Test Circuit Rev.
Absolute value trimming allows the user to program gain accurately to 0. Monolithic construction and laser wafer trimming allow the tight matching and tracking of circuit components, thus insuring AD performance.
The value of RG also determines the transconductance of the preamp stage. As RG is reduced for larger gains, the transconductance increases asymptotically to that of the input ad6222. This has the following three important advantages: Input Transistor Q1 and Input Transistor Q2 provide a single differential-pair bipolar input for high precision datasehet Figure Unity-Gain Subtractor A3 removes any common-mode signal, yielding a single-ended output referred to the REF pin potential.
In a typical application shown in Figure 17, a gain of 10 is required to receive and amplify a 0 to 20 mA signal from the AD current transmitter. In applications where transmission is over long distances, line impedance can be significant so that differential voltage measurement is essential. The error budget detailed in Table 5 ac622 how to calculate the effect of various error sources on circuit accuracy. The gain-bandwidth product determined by C1, C2, and the preamp transconductance increases with programmed gain, thus optimizing frequency response.
The higher cost of the homebrew circuit is dominated in this case by the matched resistor network. One could also realize a homebrew design using cheaper discrete resistors that are either trimmed or hand selected to give high common-mode rejection.
This level of common-mode rejection, however, degrades significantly over temperature due to the drift mismatch of the discrete resistors. This is because a two op amp type instrumentation amplifier has two op amps at its inputs, both contributing to the overall noise.
Table 6 shows required values of RG for various gains. For any arbitrary gain, RG can be calculated by using the formula The reference terminal provides a direct means of injecting a precise offset to the output, with an allowable range of 2 V within the supply voltages.
AD622 data sheet
Parasitic resistance should be kept to a minimum for optimum CMR. This is true for all gains and power on and off, which is useful if the signal source and amplifier are powered separately.
For longer time periods, the input current should not exceed 6 mA. For input voltages beyond the supplies, a protection resistor should be placed in series with each input to limit the current to 6 mA. These can be the same resistors as those used in the RFI filter.
Low leakage diodes such as the BAV can be placed at the inputs to reduce the required protection resistance. The output error is divided by G when referred to the input. In practice, the input errors dominate at high gains and the output errors dominate at low gains. The total VOS for a given gain is calculated as follows: The disturbance may appear as a small dc offset voltage.
High frequency signals can be filtered with a low-pass, RC network placed at the input of the instrumentation amplifier, as shown in Figure In addition, this RC input network also provides additional input overload protection see the Input Protection section. Input bias currents are those currents necessary to bias the input transistors of an amplifier. There must be a direct return path for these currents; therefore, when amplifying floating input sources such as transformers or ac-coupled sources, there must be a dc path from each input to ground as shown in Figure 20, Figure 21, and Figure With this differential filter in place and operating at gain ofthe typical dc offset shift over a frequency range of 1 Hz to 20 MHz is less than 1.
The input resistors should be selected to be high enough to isolate the sensor from the CC and C D capacitors but low enough not to influence system noise.
The tolerance of the CD capacitor is less critical. E Page 13 of 16 A 8 4. E Page 16 of D – Princeton University.
AD Datasheet and Product Info | Analog Devices
Review of LR circuits. Care Coordination Plus Referral Form.
Lab 9 in this note. Lab 1 in this note. Series and Parallel Circuits. High Temperature, Low Drift, Micropower 2.