SNAS809C December   2021  – September 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

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DBV|6
  • YBH|4
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.4 Thermal Hysteresis

Thermal hysteresis is measured with the REF35 soldered to a PCB, similar to a real-world application. Thermal hysteresis for the device is defined as the change in output voltage after operating the device at 25°C, cycling the device through the specified temperature range, and returning to 25°C. The PCB was baked at 150°C for 30 minutes before thermal hysteresis was measured. Use Equation 2 to calculate the thermal hysteresis:

Equation 2. REF35

where

  • VHYST = thermal hysteresis (in units of ppm)
  • VNOM = the specified output voltage
  • VPRE = output voltage measured at 25°C pre-temperature cycling
  • VPOST = output voltage measured after the device has cycled from 25°C through the specified temperature range of –40°C to +85°C or –40°C to +105°C and returns to 25°C.

The graphs below show the typical thermal hysteresis distribution across various temperature ranges in two cycles.

REF35 Thermal Hysteresis Distribution –40ºC to 85ºC, Cycle 1 Figure 7-7 Thermal Hysteresis Distribution
–40ºC to 85ºC, Cycle 1
REF35 Thermal Hysteresis Distribution –40ºC to 105ºC, Cycle 1Figure 7-9 Thermal Hysteresis Distribution
–40ºC to 105ºC, Cycle 1
REF35 Thermal Hysteresis Distribution –40ºC to 85ºC, Cycle 2Figure 7-8 Thermal Hysteresis Distribution
–40ºC to 85ºC, Cycle 2
REF35 Thermal Hysteresis Distribution –40ºC to 105ºC, Cycle 2Figure 7-10 Thermal Hysteresis Distribution
–40ºC to 105ºC, Cycle 2