SLOS456O January   2005  – June 2024

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  LM4040A20I, LM4040B20I Electrical Characteristics
    6. 6.6  LM4040C20I, LM4040D20I Electrical Characteristics
    7. 6.7  LM4040C20Q, LM4040D20Q Electrical Characteristics
    8. 6.8  LM4040A25I, LM4040B25I Electrical Characteristics
    9. 6.9  LM4040C25I, LM4040D25I Electrical Characteristics
    10. 6.10 LM4040C25Q, LM4040D25Q Electrical Characteristics
    11. 6.11 LM4040A30I, LM4040B30I Electrical Characteristics
    12. 6.12 LM4040C30I, LM4040D30I Electrical Characteristics
    13. 6.13 LM4040C30Q, LM4040D30Q Electrical Characteristics
    14. 6.14 LM4040A41I, LM4040B41I Electrical Characteristics
    15. 6.15 LM4040C41I, LM4040D41I Electrical Characteristics
    16. 6.16 LM4040A50I, LM4040B50I Electrical Characteristics
    17. 6.17 LM4040C50I, LM4040D50I Electrical Characteristics
    18. 6.18 LM4040C50Q, LM4040D50Q Electrical Characteristics
    19. 6.19 LM4040A82I, LM4040B82I Electrical Characteristics
    20. 6.20 LM4040C82I, LM4040D82I Electrical Characteristics
    21. 6.21 LM4040A10I, LM4040B10I Electrical Characteristics
    22. 6.22 LM4040C10I, LM4040D10I Electrical Characteristics
    23. 6.23 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shunt Reference
  9. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 LM4040 Voltage and Accuracy Choice
        2. 8.2.2.2 Cathode and Load Currents
        3. 8.2.2.3 Output Capacitor
        4. 8.2.2.4 SOT-23 Connections
        5. 8.2.2.5 Start-Up Characteristics
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Related Links
    2. 9.2 Trademarks
    3. 9.3 Electrostatic Discharge Caution
    4. 9.4 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.1 LM4040 Voltage and Accuracy Choice

When using LM4040 as a reference for an ADC, the ADC's FSR (Full Scale Range), Resolution and LSB must be determined. LSB can be determined by:

      LSB=FSR/(2N-1)

With N being the resolution or Number of Bits. FSR and Resolution can be determined by the ADC's datasheet.

Vref can be determined by:

      Vref=FSR+LSB

Though modern data converters use calibration techniques to compensate for any error introduced by a Vref's inaccuracy, it is best to use the highest accuracy available. This is due to errors in the calibration method that may allow some non-linearities introduced by the Vref's initial accuracy.

A good example is the LM4040x-41 that is designed to be a cost-effective voltage reference as required in 12-bit data-acquisition systems. For 12-bit systems operating from 5-V supplies (see Figure 8-1), the LM4040A-41 (4.096V, 0.01%) only introduces 4 LSBs (4mV) of possible error in a system that consists of 4096 LSBs.