SBAS815A February   2017  – June 2017 ADS114S06 , ADS114S08

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Functional Block Diagram
  4. 4 Revision History
  5. 5 Device Family Comparison Table
  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 Characteristics
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 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  Multiplexer
      2. 9.3.2  Low-Noise Programmable Gain Amplifier
        1. 9.3.2.1 PGA Input-Voltage Requirements
        2. 9.3.2.2 PGA Rail Flags
        3. 9.3.2.3 Bypassing the PGA
      3. 9.3.3  Voltage Reference
        1. 9.3.3.1 Internal Reference
        2. 9.3.3.2 External Reference
        3. 9.3.3.3 Reference Buffers
      4. 9.3.4  Clock Source
      5. 9.3.5  Delta-Sigma Modulator
      6. 9.3.6  Digital Filter
        1. 9.3.6.1 Low-Latency Filter
          1. 9.3.6.1.1 Low-Latency Filter Frequency Response
          2. 9.3.6.1.2 Data Conversion Time for the Low-Latency Filter
        2. 9.3.6.2 Sinc3 Filter
          1. 9.3.6.2.1 Sinc3 Filter Frequency Response
          2. 9.3.6.2.2 Data Conversion Time for the Sinc3 Filter
        3. 9.3.6.3 Note on Conversion Time
        4. 9.3.6.4 50-Hz and 60-Hz Line Cycle Rejection
        5. 9.3.6.5 Global Chop Mode
      7. 9.3.7  Excitation Current Sources (IDACs)
      8. 9.3.8  Bias Voltage Generation
      9. 9.3.9  System Monitor
        1. 9.3.9.1 Internal Temperature Sensor
        2. 9.3.9.2 Power Supply Monitors
        3. 9.3.9.3 Burn-Out Current Sources
      10. 9.3.10 Status Register
        1. 9.3.10.1 POR Flag
        2. 9.3.10.2 RDY Flag
        3. 9.3.10.3 PGA Output Voltage Rail Monitors
        4. 9.3.10.4 Reference Monitor
      11. 9.3.11 General-Purpose Inputs and Outputs (GPIOs)
      12. 9.3.12 Low-Side Power Switch
      13. 9.3.13 Cyclic Redundancy Check (CRC)
      14. 9.3.14 Calibration
        1. 9.3.14.1 Offset Calibration
        2. 9.3.14.2 Gain Calibration
    4. 9.4 Device Functional Modes
      1. 9.4.1 Reset
        1. 9.4.1.1 Power-On Reset
        2. 9.4.1.2 RESET Pin
        3. 9.4.1.3 Reset by Command
      2. 9.4.2 Power-Down Mode
      3. 9.4.3 Standby Mode
      4. 9.4.4 Conversion Modes
        1. 9.4.4.1 Continuous Conversion Mode
        2. 9.4.4.2 Single-Shot Conversion Mode
        3. 9.4.4.3 Programmable Conversion Delay
    5. 9.5 Programming
      1. 9.5.1 Serial Interface
        1. 9.5.1.1 Chip Select (CS)
        2. 9.5.1.2 Serial Clock (SCLK)
        3. 9.5.1.3 Serial Data Input (DIN)
        4. 9.5.1.4 Serial Data Output and Data Ready (DOUT/DRDY)
        5. 9.5.1.5 Data Ready (DRDY)
        6. 9.5.1.6 Timeout
      2. 9.5.2 Data Format
      3. 9.5.3 Commands
        1. 9.5.3.1  NOP
        2. 9.5.3.2  WAKEUP
        3. 9.5.3.3  POWERDOWN
        4. 9.5.3.4  RESET
        5. 9.5.3.5  START
        6. 9.5.3.6  STOP
        7. 9.5.3.7  SYOCAL
        8. 9.5.3.8  SYGCAL
        9. 9.5.3.9  SFOCAL
        10. 9.5.3.10 RDATA
        11. 9.5.3.11 RREG
        12. 9.5.3.12 WREG
      4. 9.5.4 Reading Data
        1. 9.5.4.1 Read Data Direct
        2. 9.5.4.2 Read Data by RDATA Command
        3. 9.5.4.3 Sending Commands When Reading Data
      5. 9.5.5 Interfacing with Multiple Devices
    6. 9.6 Register Map
      1. 9.6.1 Configuration Registers
        1. 9.6.1.1  Device ID Register (address = 00h) [reset = xxh]
          1. Table 26. Device ID (ID) Register Field Descriptions
        2. 9.6.1.2  Device Status Register (address = 01h) [reset = 80h]
          1. Table 27. Device Status (STATUS) Register Field Descriptions
        3. 9.6.1.3  Input Multiplexer Register (address = 02h) [reset = 01h]
          1. Table 28. Input Multiplexer (INPMUX) Register Field Descriptions
        4. 9.6.1.4  Gain Setting Register (address = 03h) [reset = 00h]
          1. Table 29. Gain Setting (PGA) Register Field Descriptions
        5. 9.6.1.5  Data Rate Register (address = 04h) [reset = 14h]
          1. Table 30. Data Rate (DATARATE) Register Field Descriptions
        6. 9.6.1.6  Reference Control Register (address = 05h) [reset = 10h]
          1. Table 31. Reference Control (REF) Register Field Descriptions
        7. 9.6.1.7  Excitation Current Register 1 (address = 06h) [reset = 00h]
          1. Table 32. Excitation Current Register 1 (IDACMAG) Register Field Descriptions
        8. 9.6.1.8  Excitation Current Register 2 (address = 07h) [reset = FFh]
          1. Table 33. Excitation Current Register 2 (IDACMUX) Register Field Descriptions
        9. 9.6.1.9  Sensor Biasing Register (address = 08h) [reset = 00h]
          1. Table 34. Sensor Biasing (VBIAS) Register Field Descriptions
        10. 9.6.1.10 System Control Register (address = 09h) [reset = 10h]
          1. Table 35. System Control (SYS) Register Field Descriptions
        11. 9.6.1.11 Reserved Register (address = 0Ah) [reset = 00h]
          1. Table 36. Reserved Register Field Descriptions
        12. 9.6.1.12 Offset Calibration Register 1 (address = 0Bh) [reset = 00h]
          1. Table 37. Offset Calibration Register 1 (OFCAL0) Register Field Descriptions
        13. 9.6.1.13 Offset Calibration Register 2 (address = 0Ch) [reset = 00h]
          1. Table 38. Offset Calibration Register 2 (OFCAL1) Register Field Descriptions
        14. 9.6.1.14 Reserved Register (address = 0Dh) [reset = 00h]
          1. Table 39. Reserved Register Field Descriptions
        15. 9.6.1.15 Gain Calibration Register 1 (address = 0Eh) [reset = 00h]
          1. Table 40. Gain Calibration Register 1 (FSCAL0) Field Descriptions
        16. 9.6.1.16 Gain Calibration Register 2 (address = 0Fh) [reset = 40h]
          1. Table 41. Gain Calibration Register 2 (FSCAL1) Field Descriptions
        17. 9.6.1.17 GPIO Data Register (address = 10h) [reset = 00h]
          1. Table 42. GPIO Data (GPIODAT) Register Field Descriptions
        18. 9.6.1.18 GPIO Configuration Register (address = 11h) [reset = 00h]
          1. Table 43. GPIO Configuration (GPIOCON) Register Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Serial Interface Connections
      2. 10.1.2 Analog Input Filtering
      3. 10.1.3 External Reference and Ratiometric Measurements
      4. 10.1.4 Establishing a Proper Input Voltage
      5. 10.1.5 Unused Inputs and Outputs
      6. 10.1.6 Pseudo Code Example
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Register Settings
      3. 10.2.3 Application Curves
    3. 10.3 Do's and Don'ts
  11. 11Power Supply Recommendations
    1. 11.1 Power Supplies
    2. 11.2 Power-Supply Sequencing
    3. 11.3 Power-On Reset
    4. 11.4 Power-Supply Decoupling
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Development Support
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Related Links
    4. 13.4 Receiving Notification of Documentation Updates
    5. 13.5 Community Resources
    6. 13.6 Trademarks
    7. 13.7 Electrostatic Discharge Caution
    8. 13.8 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

10.1.3 External Reference and Ratiometric Measurements

The full-scale range of the ADS114S0x is defined by the reference voltage and the PGA gain
(FSR = ±VREF / Gain). An external reference can be used instead of the integrated 2.5-V reference to adapt the FSR to the specific system needs. An external reference must be used if VIN > 2.5 V. For example, an external
5-V reference and an AVDD = 5 V are required in order to measure a single-ended signal that can swing between 0 V and 5 V.

The reference inputs of the device also allow the implementation of ratiometric measurements. In a ratiometric measurement, the same excitation source that is used to excite the sensor is also used to establish the reference for the ADC. As an example, a simple form of a ratiometric measurement uses the same current source to excite both the resistive sensor element (such as an RTD) and another resistive reference element that is in series with the element being measured. The voltage that develops across the reference element is used as the reference source for the ADC. Because current noise and drift are common to both the sensor measurement and the reference, these components cancel out in the ADC transfer function. The output code is only a ratio of the sensor element and the value of the reference resistor. The value of the excitation current source itself is not part of the ADC transfer function.

The example in the Typical Application section describes a system that uses a ratiometric measurement. One excitation current source is used to drive a reference resistor and an RTD. The ADC measurement represents a ratiometric measurement between the RTD value and a known reference resistor value.