JAJSNM7 December   2021 REF35

ADVANCE INFORMATION  

  1. 特長
  2. アプリケーション
  3. 説明
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  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. Parameter Measurement Information
    1. 8.1 Solder Heat Shift
    2. 8.2 Temperature Coefficient
    3. 8.3 Long-Term Stability
    4. 8.4 Thermal Hysteresis
    5. 8.5 Noise Performance
      1. 8.5.1 Low Frequency (1/f) Noise
      2. 8.5.2 Broadband Noise
    6. 8.6 Power Dissipation
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Supply Voltage
      2. 9.3.2 EN Pin
      3. 9.3.3 NR Pin
    4. 9.4 Device Functional Modes
      1. 9.4.1 Basic Connections
      2. 9.4.2 スタートアップ
      3. 9.4.3 出力過渡動作
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application: Negative Reference Voltage
    3. 10.3 Typical Application: Precision Power Supply and Reference
      1. 10.3.1 Design Requirements
      2. 10.3.2 Detailed Design Procedure
        1. 10.3.2.1 リファレンスの選択
        2. 10.3.2.2 Input and Output Capacitors
        3. 10.3.2.3 Selection of ADC
      3. 10.3.3 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 サポート・リソース
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ(パッケージ|ピン)
サーマルパッド・メカニカル・データ
発注情報

Solder Heat Shift

The materials used in the manufacture of the REF35 have differing coefficients of thermal expansion, resulting in stress on the device die when the part is heated. Mechanical and thermal stress on the device die can cause the output voltages to shift, degrading the initial accuracy specifications of the product. Reflow soldering is a common cause of this error.

In order to illustrate this effect, a total of 32 devices were soldered on two printed circuit boards [16 devices on each printed circuit board (PCB)] using lead-free solder paste and the paste manufacturer suggested reflow profile. The reflow profile is as shown in Figure 8-1. The printed circuit board is comprised of FR4 material. The board thickness is TBD mm and the area is TBD mm × TBD mm.

GUID-0E178243-FBF7-4E52-B87D-BF3FF23E449C-low.png Figure 8-1 Reflow Profile

The reference output voltage is measured before and after the reflow process; the typical shift is displayed in Figure 8-2. Although all tested units exhibit very low shifts (< TBD%), higher shifts are also possible depending on the size, thickness, and material of the printed circuit board. An important note is that the histograms display the typical shift for exposure to a single reflow profile. Exposure to multiple reflows, as is common on PCBs with surface-mount components on both sides, causes additional shifts in the output bias voltage. If the PCB is exposed to multiple reflows, the device must be soldered in the last pass to minimize its exposure to thermal stress.

GUID-32C95F0F-ABA7-47FB-9BB6-37CAFBCDD9D2-low.gif Figure 8-2 Solder Heat Shift Distribution, VREF (%)