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

7.3 Long-Term Stability

One of the key performance parameters of the REF35 references is long-term stability also known as long-term drift. The long-term stability value is tested in a setup that reflects standard PCB board manufacturing practices. The boards are made of standard FR4 material and the board does not have special cuts or grooves around the devices to relieve the mechanical stress of the PCB. The devices and boards in this test do not undergo high temperature burn in post-soldering prior to testing. These conditions reflect a real world use case scenario and common manufacturing techniques.

During the long-term stability testing, precautions are taken to make sure that only the long-term stability drift is measured. The boards are maintained at 35°C in an oil bath. The oil bath makes sure that the temperature is constant across the device over time compared to an air oven. The measurements are captured every 30 minutes with a calibrated 8.5 digit multimeter.

The typical long-term stability characteristic is expressed as a deviation of the reference voltage output over time.

Figure 7-5 shows that the typical drift value for the REF35 6-pin SOT-23 package is 40ppm from 0 to 1000 hours and 55ppm from 0 to 2000 hours. It is important to understand that long-term stability is not ensured by design and that the value is typical. The REF35 will experience the highest drift in the initial 1000 hr. Subsequent deviation is typically lower than first 1000 hr.

REF35 Long Term Stability - 2000 hours (VREF)
SOT23 Package
Figure 7-5 Long Term Stability - 2000 hours (VREF)
REF35 Long Term Stability - 2000 hours (VREF)
WCSP Package
Figure 7-6 Long Term Stability - 2000 hours (VREF)