SNAS809B December   2021  – May 2024 REF35

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  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 Electrical Characteristics
    6. 6.6 Electrical Characteristics YBH package
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Solder Heat Shift
    2. 7.2 Temperature Coefficient
    3. 7.3 Long-Term Stability
    4. 7.4 Thermal Hysteresis
    5. 7.5 Noise Performance
      1. 7.5.1 Low-Frequency (1/f) Noise
      2. 7.5.2 Broadband Noise
    6. 7.6 Power Dissipation
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Supply Voltage
      2. 8.3.2 EN Pin
      3. 8.3.3 NR Pin
    4. 8.4 Device Functional Modes
      1. 8.4.1 Basic Connections
      2. 8.4.2 Start-Up
      3. 8.4.3 Output Transient Behavior
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Negative Reference Voltage
      2. 9.2.2 Precision Power Supply and Reference
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Selection of Reference
          2. 9.2.2.2.2 Input and Output Capacitors
          3. 9.2.2.2.3 Selection of ADC
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Examples
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

8.3.3 NR Pin

The REF35 pin allows access to the band-gap through the NR pin. Placing a capacitor from the NR pin to GND creates a low-pass filter in combination with the internal resistance of 60 kΩ. Leakage of the capacitance directly impacts the accuracy and temperature drift. If NR functionality is used, choose a low leakage capacitor. A capacitance of 1μF creates a low-pass filter with corner frequency around 2.7Hz. Such a filter decreases the overall noise on the VREF pin. Higher capacitance results in a lower filter cut off frequency, further reducing output noise. Please note, using the capacitor on NR pin also increases start-up time.