SNOS633N December   1991  – August 2025 LM4040-N , LM4040-N-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: 2V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    6. 5.6  Electrical Characteristics: 2V LM4040-N VR Tolerance Grades 'C', 'D', And 'E'; Temperature Grade 'I'
    7. 5.7  Electrical Characteristics: 2V LM4040-N VR Tolerance Grades 'C', 'D', And 'E'; Temperature Grade 'E'
    8. 5.8  Electrical Characteristics: 2.5V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I' (AEC Grade 3)
    9. 5.9  Electrical Characteristics: 2.5V LM4040-N VR Tolerance Grades 'C', 'D', and 'E'; Temperature Grade 'I' (AEC Grade 3)
    10. 5.10 Electrical Characteristics: 2.5V LM4040-N VR Tolerance Grades 'C', 'D', And 'E'; Temperature Grade 'E' (AEC Grade 1)
    11. 5.11 Electrical Characteristics: 3V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    12. 5.12 Electrical Characteristics: 3V LM4040-N VR Tolerance Grades 'C', 'D', And 'E'; Temperature Grade 'I'
    13. 5.13 Electrical Characteristics: 3V LM4040-N VR Tolerance Grades 'C', 'D', And 'E'; Temperature Grade 'E'
    14. 5.14 Electrical Characteristics: 4.1V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    15. 5.15 Electrical Characteristics: 4.1V LM4040-N VR Tolerance Grades 'C' and 'D'; Temperature Grade 'I'
    16. 5.16 Electrical Characteristics: 5V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    17. 5.17 Electrical Characteristics: 5V LM4040-N VR Tolerance Grades 'C' And 'D'; Temperature Grade 'I'
    18. 5.18 Electrical Characteristics: 5V LM4040-N VR Tolerance Grades 'C' And 'D'; Temperature Grade 'E'
    19. 5.19 Electrical Characteristics: 8.2V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    20. 5.20 Electrical Characteristics: 8.2V Lm4040-N VR Tolerance Grades 'C' And 'D'; Temperature Grade 'I'
    21. 5.21 Electrical Characteristics: 10V LM4040-N VR Tolerance Grades 'A' And 'B'; Temperature Grade 'I'
    22. 5.22 Electrical Characteristics: 10V LM4040-N VR Tolerance Grades 'C' And 'D'; Temperature Grade 'I'
    23. 5.23 Typical Characteristics
      1. 5.23.1 Start-Up Characteristics
  7. 6 Parameter Measurement Information
  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
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Shunt Regulator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 4.1V ADC Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
      3. 8.2.3 Bounded Amplifier
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
      4. 8.2.4 Protecting Op-Amp Input
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
      5. 8.2.5 Precision ±4.096V Reference
        1. 8.2.5.1 Design Requirements
        2. 8.2.5.2 Detailed Design Procedure
      6. 8.2.6 Precision Current Sink/Source
        1. 8.2.6.1 Design Requirements
        2. 8.2.6.2 Detailed Design Procedure
    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 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Related Links
    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
    1. 11.1 SOT-23 and SC70 Package Marking Information

Package Options

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

8.1 Application Information

The LM4040-N is a precision micropower curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4040-N is available in SOT-23 and SC70 surface-mount packages. The LM4040-N 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-N remains stable. Reducing design effort is the availability of several fixed reverse breakdown voltages: 2.048V, 2.5V, 3V, 4.096V, 5V, 8.192V, and 10V. The minimum operating current increases from 60µA for the LM4040-N-2.048 and LM4040-N-2.5 to 100μA for the 10V LM4040-N. All versions have a maximum operating current of 15mA.

LM4040-Ns in the SOT-23 packages have a parasitic Schottky diode between pin 2 (−) and pin 3 (Die attach interface contact). Therefore, pin 3 of the SOT-23 package must be left floating or connected to pin 2.

LM4040-Ns in the SC70 have a parasitic Schottky diode between pin 1 (−) and pin 2 (Die attach interface contact). Therefore, pin 2 must be left floating or connected to pin1.

The 4.096V version allows single 5V 12-bit ADCs or DACs to operate with an LSB equal to 1mV. For 12-bit ADCs or DACs that operate on supplies of 10V or greater, the 8.192V version gives 2mV per LSB.

The typical thermal hysteresis specification is defined as the change in 25°C voltage measured after thermal cycling. The device is thermal cycled to temperature –40°C and then measured at 25°C. Next the device is thermal cycled to temperature 125°C and again measured at 25°C. The resulting VOUT delta shift between the 25°C measurements is thermal hysteresis. Thermal hysteresis is common in precision references and is induced by thermal-mechanical package stress. Changes in environmental storage temperature, operating temperature and board mounting temperature are all factors that can contribute to thermal hysteresis.

In a conventional shunt regulator application (Figure 8-1) , an external series resistor (RS) is connected between the supply voltage and the LM4040-N. RS determines the current that flows through the load (IL) and the LM4040-N (IQ). Since load current and supply voltage can vary, RS must be small enough to supply at least the minimum acceptable IQ to the LM4040-N even when the supply voltage is at the minimum and the load current is at the maximum value. When the supply voltage is at the maximum and IL is at the minimum, RS must be large enough so that the current flowing through the LM4040-N is less than 15mA.

RS is determined by the supply voltage, (VS), the load and operating current, (IL and IQ), and the LM4040-N's reverse breakdown voltage, VR.

Equation 1. LM4040-N LM4040-N-Q1