ZHCSGU6A september   2017  – july 2023 ADS8588H

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  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  Timing Requirements: CONVST Control
    7. 6.7  Timing Requirements: Data Read Operation
    8. 6.8  Timing Requirements: Parallel Data Read Operation, CS and RD Tied Together
    9. 6.9  Timing Requirements: Parallel Data Read Operation, CS and RD Separate
    10. 6.10 Timing Requirements: Serial Data Read Operation
    11. 6.11 Timing Requirements: Byte Mode Data Read Operation
    12. 6.12 Timing Requirements: Oversampling Mode
    13. 6.13 Timing Requirements: Exit Standby Mode
    14. 6.14 Timing Requirements: Exit Shutdown Mode
    15. 6.15 Switching Characteristics: CONVST Control
    16. 6.16 Switching Characteristics: Parallel Data Read Operation, CS and RD Tied Together
    17. 6.17 Switching Characteristics: Parallel Data Read Operation, CS and RD Separate
    18. 6.18 Switching Characteristics: Serial Data Read Operation
    19. 6.19 Switching Characteristics: Byte Mode Data Read Operation
    20. 6.20 Timing Diagrams
    21. 6.21 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Analog Inputs
      2. 7.3.2  Analog Input Impedance
      3. 7.3.3  Input Clamp Protection Circuit
      4. 7.3.4  Programmable Gain Amplifier (PGA)
      5. 7.3.5  Third-Order, Low-Pass Filter (LPF)
      6. 7.3.6  ADC Driver
      7. 7.3.7  Digital Filter and Noise
      8. 7.3.8  Reference
        1. 7.3.8.1 Internal Reference
        2. 7.3.8.2 External Reference
        3. 7.3.8.3 Supplying One VREF to Multiple Devices
      9. 7.3.9  ADC Transfer Function
      10. 7.3.10 ADS8588H Device Family Comparison
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Interface: Pin Description
        1. 7.4.1.1  REFSEL (Input)
        2. 7.4.1.2  RANGE (Input)
        3. 7.4.1.3  STBY (Input)
        4. 7.4.1.4  PAR/SER/BYTE SEL (Input)
        5. 7.4.1.5  CONVSTA, CONVSTB (Input)
        6. 7.4.1.6  RESET (Input)
        7. 7.4.1.7  RD/SCLK (Input)
        8. 7.4.1.8  CS (Input)
        9. 7.4.1.9  OS[2:0]
        10. 7.4.1.10 BUSY (Output)
        11. 7.4.1.11 FRSTDATA (Output)
        12. 7.4.1.12 DB15/BYTE SEL
        13. 7.4.1.13 DB14/HBEN
        14. 7.4.1.14 DB[13:9]
        15. 7.4.1.15 DB8/DOUTB
        16. 7.4.1.16 DB7/DOUTA
        17. 7.4.1.17 DB[6:0]
      2. 7.4.2 Device Modes of Operation
        1. 7.4.2.1 Power-Down Modes
          1. 7.4.2.1.1 Standby Mode
          2. 7.4.2.1.2 Shutdown Mode
        2. 7.4.2.2 Conversion Control
          1. 7.4.2.2.1 Simultaneous Sampling on All Input Channels
          2. 7.4.2.2.2 Simultaneous Sampling Two Sets of Input Channels
        3. 7.4.2.3 Data Read Operation
          1. 7.4.2.3.1 Parallel Data Read
          2. 7.4.2.3.2 Parallel Byte Data Read
          3. 7.4.2.3.3 Serial Data Read
          4. 7.4.2.3.4 Data Read During Conversion
        4. 7.4.2.4 Oversampling Mode of Operation
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 接收文档更新通知
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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7.3.3 Input Clamp Protection Circuit

The ADS8588H features an internal clamp protection circuit (as shown in Figure 7-1) on each of the eight analog input channels, respectively. Use of external protection circuits is recommended as a secondary protection scheme to protect the device. Using external protection devices helps with protection against surges, electrostatic discharge (ESD), and electrical fast transient (EFT) conditions.

The input clamp protection circuit on the ADS8588H allows each analog input to swing up to a maximum voltage of ±15 V. Beyond an input voltage of ±15 V, the input clamp circuit turns on, still operating off the single 5-V supply. Figure 7-2 illustrates a typical current versus voltage characteristic curve for the input clamp. There is no current flow in the clamp circuit for input voltages up to ±15 V. Beyond this voltage, the input clamp circuit turns on.

GUID-04D75FE1-8DE9-4862-B305-316B8E82F32D-low.gifFigure 7-2 I-V Curve for an Input Clamp Protection Circuit (AVDD = 5 V)

For input voltages above the clamp threshold, make sure that input current never exceeds the absolute maximum rating (see the Absolute Maximum Ratings table) of ±10 mA to prevent any damage to the device. A small series resistor placed in series with the analog inputs, as shown in Figure 7-3, is an effective way to limit the input current. In addition to limiting the input current, this resistor can also provide an antialiasing, low-pass filter when coupled with a capacitor. In order to maintain the dc accuracy of the system, matching the external source impedance on the AIN_nP input pin with an equivalent resistance on the AIN_nGND pin is recommended. This matching helps cancel any additional offset error contributed by the external resistance.

GUID-7E489344-98CD-48E2-8DEC-B2C3CD39DB50-low.gifFigure 7-3 Matching Input Resistors on the Analog Inputs of the ADS8588H

The input overvoltage protection clamp on the ADS8588H is intended to control transient excursions on the input pins. Leaving the device in a state such that the clamp circuit is activated for extended periods of time in normal or power-down mode is not recommended because this fault condition can degrade device performance and reliability.