SLPS755B October   2023  – October 2025 RES11A-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 DC Measurement Configurations
    2. 6.2 AC Measurement Configurations
    3. 6.3 Error Notation and Units
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Ratiometric Matching for Low Gain Error
        1. 7.3.1.1 Absolute and Ratiometric Tolerances
      2. 7.3.2 Ratiometric Drift
        1. 7.3.2.1 Long-Term Stability
      3. 7.3.3 Predictable Voltage Coefficient
      4. 7.3.4 Ultra-Low Noise
    4. 7.4 Device Functional Modes
      1. 7.4.1 Per-Resistor Limitations
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Amplifier Feedback Circuit
        1. 8.1.1.1 Amplifier Feedback Circuit Example
      2. 8.1.2 Voltage Divider Circuit
        1. 8.1.2.1 Voltage Divider Circuit Example
        2. 8.1.2.2 Voltage-Divider Circuit Drift
      3. 8.1.3 Discrete Difference Amplifier
        1. 8.1.3.1 Difference-Amplifier Common-Mode Rejection Analysis
        2. 8.1.3.2 Difference-Amplifier Gain Error Analysis
      4. 8.1.4 Discrete Instrumentation Amplifiers
      5. 8.1.5 Fully Differential Amplifier
      6. 8.1.6 Unconventional Circuits
        1. 8.1.6.1 Single-Channel Voltage Divider
        2. 8.1.6.2 Single-Channel Amplifier Gain
          1. 8.1.6.2.1 Gain Scaling the RES60A-Q1 With the RES11A-Q1
      7. 8.1.7 Unconventional Instrumentation Amplifiers
    2. 8.2 Typical Application
      1. 8.2.1 Common-Mode Shifting Input Stage
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 PSpice® for TI
        2. 9.1.1.2 TINA-TI™ Simulation Software (Free Download)
        3. 9.1.1.3 TI Reference Designs
        4. 9.1.1.4 Analog Filter Designer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.3 Predictable Voltage Coefficient

The voltage coefficients of the RES11A-Q1 are largely related to self-heating, where the power dissipated in the device raises the die temperature. As previously mentioned, the commonality of this temperature rise leads to a comparable shift in each resistor, such that the divider ratio is well preserved.

Applying voltage V across resistor R results in the loss of a corresponding power dissipation of P = V2 / R, in the form of heat in the device die. This heat leads to a localized increase in the junction temperature, which in turn causes the same parametric shifts previously discussed in the context of temperature coefficients. TCR is specified as a function of ambient temperature; therefore, use the effective junction-to-ambient thermal resistance to determine the effective temperature rise and calculate the nominal or expected shift.

Equation 16. R expected = R initial + V R 2 R × R θJA effective × TCR abs × R initial

If two dividers are biased simultaneously, the power dissipation of both dividers must be summed before calculating the associated junction temperature rise using the junction-to-ambient thermal resistance.

The following figures show a data set from one RES11A40-Q1 unit tested at various voltages.

RES11A-Q1 RIN Resistance vs Divider VoltageFigure 7-7 RIN Resistance vs Divider Voltage
RES11A-Q1 RG Resistance vs Divider VoltageFigure 7-8 RG Resistance vs Divider Voltage

The difference of the expected value of R from the actual value of R describes the actual-to-expected mismatch error of R, due to non-temperature-related effects on the voltage coefficient. Similar to the logarithmic conformity error of a logarithmic amplifier or the integrated nonlinearity error of an ADC, this error describes the deviations of the actual device behavior from the predictable behavior. While the absolute magnitude of the shift varies, the slope or trend is predictable. Note that measurement noise and leakages can easily increase the measured error; follow best practices such as cleaning and baking circuit boards after assembly to minimize external errors and improve repeatability.

The change in the measured value of R is divided by the change in bias voltage VR to calculate the effective voltage coefficient of resistance. For example, the voltage coefficient of RIN1 is ΔRIN1 divided by ΔVRIN1.

Equation 17. Voltage coefficient (Ω/V) = R final – R initial V R(final) – V R(initial)
RES11A-Q1 Resistor Actual-to-expected Mismatch vs Divider Voltage, AbsoluteFigure 7-9 Resistor Actual-to-expected Mismatch vs Divider Voltage, Absolute
RES11A-Q1 Resistor Actual-to-expected Mismatch vs Divider Voltage, NormalizedFigure 7-10 Resistor Actual-to-expected Mismatch vs Divider Voltage, Normalized

This exercise is repeated for each Rx, tD1, tD2, and tM, to calculate the voltage coefficients associated with each parameter. For example, the RES11A-Q1 has a typical absolute voltage coefficient of approximately ±0.24Ω/V for RIN and RG. When considered in ratiometric terms, the typical voltage coefficient of tD1 or tD2 is ±0.4ppm/V, and the voltage coefficient of tM is ±0.24ppm/V.