SBOSA80 December   2021 REF20-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 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 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 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
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 VREF and VBIAS Tracking
      2. 9.3.2 Low Temperature Drift
      3. 9.3.3 Load Current
    4. 9.4 Device Functional Modes
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Low-Side, Current-Sensing Application
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Shunt Resistor
          2. 10.2.1.2.2 Differential Amplifier
          3. 10.2.1.2.3 Voltage Reference
          4. 10.2.1.2.4 Error Calculations
          5. 10.2.1.2.5 Application Curves
  11. 11Power-Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

The voltage reference for this application must have the following features:

  1. Dual output (3.0 V and 1.5 V)
  2. Low drift
  3. Low tracking errors between the two outputs

For this design, the REF2030-Q1 is used. The REF20xx-Q1 topology is as shown in the Section 9.2 section.

The REF2030-Q1 is an excellent choice for this application because of its dual output. The temperature drift of
8 ppm/°C and initial accuracy of 0.05% make the errors resulting from the voltage reference minimal in this application. In addition, there is minimal mismatch between the two outputs and both outputs track very well across temperature, as shown in Figure 10-4 and Figure 10-5.

GUID-9E285497-9F86-43E4-8C54-AC85053D2CE8-low.pngFigure 10-4 VREF – 2 × VBIAS Distribution
(At TA = 25°C)
GUID-57B2709F-2534-4045-8537-73F7446E7D7D-low.pngFigure 10-5 Distribution of VREF – 2 × VBIAS Drift Tracking Over Temperature