ZHCSM80G October   2020  – September 2023 REF70

PRODMIX  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  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 接收文档更新通知
    3. 11.3 支持资源
    4. 11.4 Trademarks
    5. 11.5 静电放电警告
    6. 11.6 术语表
  13. 12Mechanical, Packaging, and Orderable Information

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8.4.1 1/f Noise

1/f noise, also known as flicker noise, is a low frequency noise that affects the device output voltage which can affect precision measurements in ADCs. This noise increases proportionally with output voltage and operating temperature. It is measured by filtering the output from 0.1-Hz to 10-Hz. Since the 1/f noise is an extremely low value, the frequency of interest needs to be amplified and band-pass filtered. This is done by using a high-pass filter to block the DC voltage. The resulting noise is then amplified by a gain of 1000. The bandpass filter is created by a series of high-pass and low-pass filter that adds additional gain to make it more visible on a oscilloscope as shown in Figure 8-9. 1/f noise must be tested in a Faraday cage enclosure to block environmental noise.

GUID-20201217-CA0I-5K1M-FFB1-BLD3DWQZFNNP-low.gifFigure 8-9 1/f Noise Test Setup

Typical 1/f noise (0.1-Hz to 10-Hz) distribution can be seen in Figure 8-10. The noise is measured at two different supply voltages. The REF70 noise performance is not impacted by supply voltage.

GUID-20230504-SS0I-VHNJ-LGQP-WH9BGD9MRN6M-low.svg Figure 8-10 0.1-Hz to 10-Hz Voltage Noise Distribution
The 1/f noise is in such a low frequency range that it is not practical to filter out which makes it a key parameter for ultra-low noise measurements. Noise sensitive designs must use the lowest 1/f noise for the highest precision measurements. Figure 8-11 shows the effect of 1/f noise over 10s.
GUID-20200929-CA0I-SXMV-PBHZ-FSN1SCDMJCBL-low.gif Figure 8-11 0.1-Hz to 10-Hz Voltage Noise