SBAS705B June   2015  – April 2020 ADS131E08S

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Power Application: Three-Phase Voltage and Current Connection
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
    1.     Pin 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 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Measurements
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Electromagnetic Interference (EMI) Filter
      2. 9.3.2  Input Multiplexer
        1. 9.3.2.1 Device Noise Measurements
        2. 9.3.2.2 Test Signals (TestP and TestN)
        3. 9.3.2.3 Temperature Sensor (TempP, TempN)
        4. 9.3.2.4 Power-Supply Measurements (MVDDP, MVDDN)
      3. 9.3.3  Analog Input
      4. 9.3.4  PGA Settings and Input Range
        1. 9.3.4.1 Input Common-Mode Range
      5. 9.3.5  ΔΣ Modulator
      6. 9.3.6  Clock
      7. 9.3.7  Digital Decimation Filter
      8. 9.3.8  Voltage Reference
      9. 9.3.9  Input Out-of-Range Detection
      10. 9.3.10 General-Purpose Digital I/O (GPIO)
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Down
      2. 9.4.2 Reset
      3. 9.4.3 Conversion Mode
        1. 9.4.3.1 START Pin Low-to-High Transition or START Command Sent
        2. 9.4.3.2 Input Signal Step
        3. 9.4.3.3 Continuous Conversion Mode
    5. 9.5 Programming
      1. 9.5.1 SPI Interface
        1. 9.5.1.1 Chip Select (CS)
        2. 9.5.1.2 Serial Clock (SCLK)
        3. 9.5.1.3 Data Input (DIN)
        4. 9.5.1.4 Data Output (DOUT)
        5. 9.5.1.5 Data Ready (DRDY)
      2. 9.5.2 Data Retrieval
        1. 9.5.2.1 Status Word
        2. 9.5.2.2 Readback Length
        3. 9.5.2.3 Data Format
      3. 9.5.3 SPI Command Definitions
        1. 9.5.3.1  WAKEUP: Exit STANDBY Mode
        2. 9.5.3.2  STANDBY: Enter STANDBY Mode
        3. 9.5.3.3  RESET: Reset Registers to Default Values
        4. 9.5.3.4  START: Start Conversions
        5. 9.5.3.5  STOP: Stop Conversions
        6. 9.5.3.6  OFFSETCAL: Channel Offset Calibration
        7. 9.5.3.7  RDATAC: Start Read Data Continuous Mode
        8. 9.5.3.8  SDATAC: Stop Read Data Continuous Mode
        9. 9.5.3.9  RDATA: Read Data
        10. 9.5.3.10 RREG: Read from Register
        11. 9.5.3.11 WREG: Write to Register
        12. 9.5.3.12 Sending Multibyte Commands
    6. 9.6 Register Map
      1. 9.6.1 Register Descriptions
        1. 9.6.1.1 ID: ID Control Register (Factory-Programmed, Read-Only) (address = 00h) [reset = D2h]
          1. Table 11. ID: ID Control Register Field Descriptions
        2. 9.6.1.2 CONFIG1: Configuration Register 1 (address = 01h) [reset = 94h]
          1. Table 12. CONFIG1: Configuration Register 1 Field Descriptions
        3. 9.6.1.3 CONFIG2: Configuration Register 2 (address = 02h) [reset = 00h]
          1. Table 14. CONFIG2: Configuration Register 2 Field Descriptions
        4. 9.6.1.4 CONFIG3: Configuration Register 3 (address = 03h) [reset = E0h]
          1. Table 15. CONFIG3: Configuration Register 3 Field Descriptions
        5. 9.6.1.5 FAULT: Fault Detect Control Register (address = 04h) [reset = 00h]
          1. Table 16. FAULT: Fault Detect Control Register Field Descriptions
        6. 9.6.1.6 CHnSET: Individual Channel Settings (address = 05h to 0Ch) [reset = 10h]
          1. Table 17. CHnSET: Individual Channel Settings Field Descriptions
        7. 9.6.1.7 FAULT_STATP: Fault Detect Positive Input Status (address = 12h) [reset = 00h]
          1. Table 18. FAULT_STATP: Fault Detect Positive Input Status Field Descriptions
        8. 9.6.1.8 FAULT_STATN: Fault Detect Negative Input Status (address = 13h) [reset = 00h]
          1. Table 19. FAULT_STATN: Fault Detect Negative Input Status Field Descriptions
        9. 9.6.1.9 GPIO: General-Purpose IO Register (address = 14h) [reset = 0Fh]
          1. Table 20. GPIO: General-Purpose IO Register Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Multiple Device Configuration
        1. 10.1.1.1 Synchronizing Multiple Devices
        2. 10.1.1.2 Standard Configuration
        3. 10.1.1.3 Daisy-Chain Configuration
      2. 10.1.2 Power Monitoring Specific Applications
      3. 10.1.3 Current Sensing
      4. 10.1.4 Voltage Sensing
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 Initialization Set Up
      1. 10.3.1 Setting the Device Up for Basic Data Capture
  11. 11Power Supply Recommendations
    1. 11.1 Power-Up Timing
    2. 11.2 Recommended External Capacitor Values
    3. 11.3 Device Connections for Unipolar Power Supplies
    4. 11.4 Device Connections for Bipolar Power Supplies
  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 Support Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.5.1.2 Serial Clock (SCLK)

Use SCLK as the SPI serial clock to shift in commands and shift out data from the device. The serial clock (SCLK) features a Schmitt-triggered input and clocks data on the DIN and DOUT pins into and out of the ADS131E08S.

Care must be taken to prevent glitches on SCLK when CS is low. Glitches as small as 1 ns in duration can be interpreted as a valid serial clock. An instruction on DIN is decoded every eight serial clocks. If instructions are suspected of being interrupted erroneously, toggle CS high and back low to reset the SPI interface, placing the device in normal operation.

For a single device, the minimum speed needed for SCLK depends on the number of channels, number of bits of resolution, and output data rate. (For multiple cascaded devices, see the Standard Configuration section.) The SCLK rate limitation, as described by Equation 7, applies to RDATAC mode.

Equation 7. tSCLK < (tDR – 4 tCLK) / (NBITS × 8 + 24)

where

  • NBITS = resolution of data for the current data rate; 16 or 24

For example, if the ADS131E08S is used with an 8-kSPS mode (24-bit resolution), the minimum SCLK speed is 1.755 MHz to shift out all the data.

Data retrieval can be done either by putting the device in read data continuous mode (RDATAC mode) or reading on demand using the read data command (RDATA). The SCLK rate limitation, as described by Equation 7, applies to RDATAC mode. When using the RDATA command, the limitation applies if data must be read in between two consecutive DRDY signals. This calculation assumes that there are no other commands issued in between data captures.

There are two methods for transmitting SCLKs to the ADS131E08S to meet the decode timing specification (tSDECODE) illustrated in Figure 1 for multiple byte commands:

  1. SCLK can be transmitted in 8-bit bursts with a gap between bursts to maintain the tSDECODE timing specification. The maximum SCLK frequency is specified in Figure 1.
  2. A continuous SCLK stream can be sent when CS is low. Verify that the SCLK speed meets the tSDECODE timing requirement. This method is not to be confused with a free-running SCLK where SCLK also operates when CS is high. A free-running SCLK operation is not supported by this device.