It operates with a 2. The outputfollows the input signal in a manner that provides the highest level of signal TL28L92 3. The product families are positioned for cost-effective applications requiring significant control processing and connectivity capabilities. Reference Inputs. The is a high gain three-stage monolithic high power amplifier.

Author:Tygozahn Tomi
Country:Pacific Islands
Language:English (Spanish)
Published (Last):22 December 2006
PDF File Size:10.74 Mb
ePub File Size:17.98 Mb
Price:Free* [*Free Regsitration Required]

A , Zer? The versatile 3-op amp design, small size, and low power make it ideal for a wide range of portable applications. A single external resistor sets any gain from 1 to The INA provides very low offset voltage 25? It operates with power supplies as low as 1.

A—ideal for battery-operated systems. All trademarks are the property of their respective owners. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. Input signals that can swing more than 0. Hz Noise 0. Good layout practice mandates the use of bypass capacitors placed close to the device pins as shown. This connection must be low-impedance to assure good common-mode rejection.

Although 15? The k? These on-chip resistors are laser trimmed to accurate absolute values. The accuracy and temperature coefficient of these resistors are included in the gain accuracy and drift specifications of the INA The stability and temperature drift of the external gain setting resistor, RG, also affects gain.

The contribution of RG to gain accuracy and drift can be directly inferred from the gain Equation 1. Low resistor values required for high gain can make wiring resistance important. Sockets add to the wiring resistance and contribute additional gain error possibly an unstable gain error in gains of approximately or greater.

To ensure stability, avoid parasitic capacitance of more than a few picofarads at the RG connections. Basic Connections Copyright? NC 1 k 25k NC k When using the SPICE model, the simulation will not converge unless a resistor is connected to the RG pins; use a very large resistor value. The amplifier is zero-corrected every 8? Upon power-up, the amplifier requires approximately ?

This design has no aliasing or flicker noise. Figure 33 shows an optional circuit for trimming the output offset voltage. The voltage applied to REF terminal is summed at the output. The op amp buffer provides low impedance at the REF terminal to preserve good common-mode rejection. The spectral noise density can be seen in detail in Figure 8.

Low frequency noise of the INA is approximately 1? VPP measured from 0. However, a path must be provided for the input bias current of both inputs. High input impedance means that this input bias current changes very little with varying input voltage.

Input circuitry must provide a path for this input bias current for proper operation. Figure 34 illustrates various provisions for an input bias current path. Without a bias current path, the inputs will float to a potential that exceeds the common-mode range of the INA, and the input amplifiers will saturate. If the differential source resistance is low, the bias current return path can be connected to one input see the thermocouple example in Figure With higher source impedance, using two equal resistors provides a balanced input with possible advantages of lower input offset voltage as a result of bias current and better high-frequency common-mode rejection.

Figure Parameters that vary over supply voltage or temperature are shown in the Typical Characteristics section of this data sheet. Most parameters vary only slightly throughout this supply voltage range—see the Typical Characteristics section. Operation at very low supply voltage requires careful attention to assure that the input voltages remain within the linear range.

Voltage swing requirements of internal nodes limit the input common-mode range with low power-supply voltage. Center tap provides bias current return. As a differential input voltage causes the output voltage to increase, however, the linear input range is limited by the output voltage swing of amplifiers A1 and A2. Thus, the linear common-mode input range is related to the output voltage of the complete amplifier.

Input overload conditions can produce an output voltage that appears normal. For example, if an input overload condition drives both input amplifiers to the respective positive output swing limit, the difference voltage measured by the output amplifier is near zero.

The output of the INA is near 0V even though both inputs are overloaded. Figure 35 illustrates a basic single-supply circuit. The output REF terminal is connected to mid-supply. Zero differential input voltage demands an output voltage of mid-supply.

Actual output voltage swing is limited to approximately 50mV above ground, when the load is referred to ground as shown. The typical characteristic curve Output Voltage Swing vs Output Current Figure 29 shows how the output voltage swing varies with output current. For instance, the inverting input cannot be connected to ground to measure a voltage connected to the noninverting input.

To illustrate the issues affecting low voltage operation, consider the circuit in Figure It shows the INA operating from a single 3V supply.

A resistor in series with the low side of the bridge assures that the bridge output voltage is within the common-mode range of the amplifier inputs. These diodes clamp the applied signal to prevent it from damaging the input circuitry. If the input signal voltage can exceed the power supplies by more than 0. This current limiting can generally be done with a series input resistor. Some signal sources are inherently current-limited and do not require limiting resistors.

Keep traces short and, when possible, use a printed circuit board PCB ground plane with surface-mount components placed as close to the device pins as possible. Place a 0. F bypass capacitor closely across the supply pins. These guidelines should be applied throughout the analog circuit to improve performance and provide benefits such as reducing the electromagnetic-interference EMI susceptibility. Instrumentation amplifiers vary in the susceptibility to radio-frequency interference RFI.

RFI can generally be identified as a variation in offset voltage or dc signal levels with changes in the interfering RF signal. As a result, the INA demonstrates remarkably low sensitivity compared to previous generation devices.

Strong RF fields may continue to cause varying offset levels, however, and may require additional shielding. It provides all the conventional dc, transient, and frequency domain analysis of SPICE as well as additional design capabilities.

Virtual instruments offer users the ability to select input waveforms and probe circuit nodes, voltages, and waveforms, creating a dynamic quick-start tool. Links to download these simulation files are given below. These resistors are included to show the four-wire sense technique immunity to line mismatches.

This method assumes the use of a four-wire RTD. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

Samples may or may not be available. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free RoHS Exempt : This component has a RoHS exemption for either 1 lead-based flip-chip solder bumps used between the die and package, or 2 lead-based die adhesive used between the die and leadframe.

TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.

Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. TI assumes no liability for applications assistance or customer product design.

Customers are responsible for their products and applications using TI components.



A , Zer? The versatile 3-op amp design, small size, and low power make it ideal for a wide range of portable applications. A single external resistor sets any gain from 1 to The INA provides very low offset voltage 25? It operates with power supplies as low as 1. A—ideal for battery-operated systems. All trademarks are the property of their respective owners.





Related Articles