SNAS856A September   2024  – March 2025 REF80

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 Thermal Information
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Heater
      2. 7.3.2 Buried Zener Reference
  9. 8 Parameter Measurement Information
    1. 8.1 Long-Term Stability
    2. 8.2 Temperature Drift
    3. 8.3 Thermal Hysteresis
    4. 8.4 Noise Performance
      1. 8.4.1 1/f Noise
      2. 8.4.2 Broadband Noise
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Application: Basic Voltage Reference Connection
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Typical Application Circuits
        1. 9.2.2.1 Precision Voltage Divider Connection
        2. 9.2.2.2 Calibration Signal
    3. 9.3 Power Supply Recommendation
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  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

8.1 Long-Term Stability

Buried zener references typically exhibit very stable long term stability and are used as an ultra stable reference for internal calibration of the system. The long-term stability value is tested in a typical setup that reflects standard PCB board manufacturing practices for references with a strain modulation structure around the device. The boards are made of standard FR4 material with 35µm of Copper. The devices have been soldered through standard reflow.

Long term stability setup is designed with utmost care to minimize impact of thermocouple error, strain impact and mechanical vibration in long term stability measurement. The boards are maintained at 25°C in an air drift oven with heater temperature set to 115°C in powered on condition for long term stability measurement.

Typical long-term stability characteristic is expressed as a deviation over time. Figure 8-1 shows the typical drift value for the VREF_Z is 3ppm from 0 to 1000 hours. Drift of REF80 gets flat after 1000 hours. Powered-up burn-in at room temperature helps REF80 to achieve best long term stability performance.

Power cycle has minimal impact on the stability of the VREF_Z and doesn't change the settled profile. Figure 8-2 shows the behavior of the output when the devices are powered off for 24 hours.

REF80 Long Term Stability (VREF_Z) Figure 8-1 Long Term Stability (VREF_Z)
REF80 Power Cycle Hysteresis Figure 8-2 Power Cycle Hysteresis