SNAS781G October   2020  – September 2023 REF70

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  REF7012 Electrical Characteristics
    6. 7.6  REF7025 Electrical Characteristics
    7. 7.7  REF7030 Electrical Characteristics
    8. 7.8  REF7033 Electrical Characteristics
    9. 7.9  REF7040 Electrical Characteristics
    10. 7.10 REF7050 Electrical Characteristics
    11. 7.11 Typical Characteristics
  9. 8 Parameter Measurement Information
    1. 8.1 Solder Heat Shift
    2. 8.2 Long-Term Stability
    3. 8.3 Thermal Hysteresis
    4. 8.4 Noise Performance
      1. 8.4.1 1/f Noise
      2. 8.4.2 Broadband Noise
    5. 8.5 Temperature Drift
    6. 8.6 Power Dissipation
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 EN Pin
    4. 9.4 Device Functional Modes
      1. 9.4.1 Basic Connections
      2. 9.4.2 Negative Reference Voltage
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Typical Application: Basic Voltage Reference Connection
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Input and Output Capacitors
            1. 10.2.1.2.1.1 Application Curve
          2. 10.2.1.2.2 Force and Sense Connection
      2. 10.2.2 Typical Application: DAC Force and Sense Reference Drive Circuit
        1. 10.2.2.1 Design Requirements
    3. 10.3 Power Supply Recommendation
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2 Long-Term Stability

One of the key parameters of the REF70 references is long-term stability also known as long-term drift. The long-term stability value was tested in a typical 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 ensure that only the long-term stability drift is being measured. The boards are maintained at 35°C in an oil bath. The oil bath ensures 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.

Typical long-term stability characteristic is expressed as a deviation over time. Figure 8-4 shows the typical drift value for the REF70 in LCCC (FKH) package is 35 ppm from 0 to 1000 hours. It is important to understand that long-term stability is not ensured by design and that the value is typical. The REF70 will experience the highest drift in the initial 1000 hr. Subsequent deviation is typically lower than previous 1000 hr.

GUID-20230504-SS0I-7Z4C-BTSC-TVBS6JJD4HSS-low.svg Figure 8-4 Long Term Stability LCCC -10000 hours (VOUT)

Figure 8-5 shows the typical drift value for the REF70 in VSSOP (DGK) package is 75 ppm from 0 to 1000 hours. It is important to understand that long-term stability is not ensured by design and that the value is typical. The REF70 will experience the highest drift in the initial 1000 hr.

GUID-20230831-SS0I-NKJD-KTMB-HWDZC0WFLGD0-low.svg Figure 8-5 Long Term Stability VSSOP -10000 hours (VOUT)