SLPS814 November   2025 RES21A-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
      3. 7.3.3 Long-Term Stability
      4. 7.3.4 Humidity Resilience
      5. 7.3.5 Ultra-Low Noise
    4. 7.4 Device Functional Modes
  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 RES21A-Q1
        3. 8.1.6.3 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

8.1.2.1 Voltage Divider Circuit Example

Consider the following example. Dividers 1 and 2 of the RES21A-Q1 are both arranged as voltage dividers, but the relative positions of RG1 and RIN2 are swapped, as are the positions of RIN1 and RG2. Both channels have the same input signal VIN, but have differing transfer functions of VOUT1 = VIN × G1 / (1 + G1) and VOUT2 = VIN × 1 / (1 + G2).

RES21A-Q1 Voltage Divider Example Circuit Figure 8-5 Voltage Divider Example Circuit

The following tables show the calculated results for several examples to illustrate the effects of the various errors. Each row in the tables represents a different hypothetical condition. The final rows of each table show the results when substituting the absolute maximum and minimum limits of tDx. The final percent error EOUTx is calculated as:

Equation 30. E OUTx = V OUTx – V OUTnom V OUTnom
Table 8-2 Calculated Errors for Voltage Divider Example, Divider 1
VIN Gnom GVDnom VOUT1nom tD1 tVD1 GVD1 VOUT1 EOUT1
5V 4 1/5 1V 60ppm –48ppm 0.19999 0.99995 –48ppm
5V 4 1/5 1V –80ppm 64ppm 0.20001 1.00006 64ppm
10V 4 1/5 2V 60ppm –48ppm 0.19999 1.99990 –48ppm
10V 4 1/5 2V –80ppm 64ppm 0.20001 2.00013 64ppm
10V 4 1/5 2V 500ppm –400ppm 0.19992 1.99920 –400ppm
10V 4 1/5 2V –500ppm 400ppm 0.20008 2.00080 400ppm
Table 8-3 Calculated Errors for Voltage Divider Example, Divider 2
VIN Gnom GVDnom VOUT2nom tD2 tVD2 GVD2 VOUT2 EOUT2
5V 4 4/5 4V 75ppm 15ppm 0.80001 4.00006 15ppm
5V 4 4/5 4V –130ppm –26ppm 0.79998 3.99990 –26ppm
10V 4 4/5 8V 75ppm 15ppm 0.80001 8.00012 15ppm
10V 4 4/5 8V –130ppm –26ppm 0.79998 7.99979 –26ppm
10V 4 4/5 8V 500ppm 100ppm 0.80008 8.00080 100ppm
10V 4 4/5 8V –500ppm –100ppm 0.79992 7.99920 –100ppm

As the examples show, the final error EOUTx of the transfer function for each divider is equivalent to the corresponding effective voltage divider error tVDx. In all cases, the magnitude of tVDx is less than the magnitude of tDx.