SLOS456N January   2005  – October 2017

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
  7. 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
  8. 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
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7 Detailed Description

7.1 Overview

The LM4040 is a precision micro-power curvature-corrected bandgap shunt voltage reference. The LM4040 has been designed for stable operation without the need of an external capacitor connected between the “+” pin and the “−” pin. If, however, a bypass capacitor is used, the LM4040 remains stable.

LM4040 offers several fixed reverse breakdown voltages: 2.048 V, 2.500 V, 3.000 V, 4.096 V, 5.000 V, 6.000, 8.192 V, and 10.000 V. The minimum operating current increases from 60 µA for the LM4040-N-2.048 and LM4040-N-2.5 to 100 μA for the 10.0-V LM4040. All versions have a maximum operating current of 15 mA.

Each reverse voltage options can be purchased with initial tolerances (at 25°C) of 0.1%, 0.2%, 0.5% and 1.0%. These reference options are denoted by A (0.1%), B (0.2%), C (0.5%) and D for (1.0%).

The LM4040xxxI devices are characterized for operation from –40°C to 85°C, and the LM4040xxxQ devices are characterized for operation from –40°C to 125°C.

7.2 Functional Block Diagram

LM4040A LM4040B LM4040C LM4040D fbd_los456.gif

7.3 Feature Description

A temperature compensated band gap voltage reference controls high gain amplifier and shunt pass element to maintain a nearly constant voltage between cathode and anode. Regulation occurs after a minimum current is provided to power the voltage divider and amplifier. Internal frequency compensation provides a stable loop for all capacitor loads. Floating shunt design is useful for both positive and negative regulation applications.

7.4 Device Functional Modes

7.4.1 Shunt Reference

LM4040 will operate in one mode, which is as a fixed voltage reference that cannot be adjusted. LM4040 does offer various Reverse Voltage options that have unique electrical characteristics detailed in the Specifications section.

In order for a proper Reverse Voltage to be developed, current must be sourced into the cathode of LM4040. The minimum current needed for proper regulation is denoted in the Specifications section as IZ,min.