SBAS852A August   2017  – February 2020 ADS114S06B , ADS114S08B

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 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 Requirements
    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 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 Digital Filter Frequency Response
        2. 9.3.6.2 Data Conversion Time
        3. 9.3.6.3 Note on Conversion Time
        4. 9.3.6.4 50-Hz and 60-Hz Line Cycle Rejection
      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 External Reference Monitor
      11. 9.3.11 General-Purpose Inputs and Outputs (GPIOs)
      12. 9.3.12 Calibration
        1. 9.3.12.1 Offset Calibration
        2. 9.3.12.2 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
    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 Interfacing with Multiple Devices
    6. 9.6 Register Map
      1. 9.6.1 Configuration Registers
      2. 9.6.2 Register Descriptions
        1. 9.6.2.1  Device ID Register (address = 00h) [reset = xxh]
          1. Table 16. Device ID (ID) Register Field Descriptions
        2. 9.6.2.2  Device Status Register (address = 01h) [reset = 80h]
          1. Table 17. Device Status (STATUS) Register Field Descriptions
        3. 9.6.2.3  Input Multiplexer Register (address = 02h) [reset = 01h]
          1. Table 18. Input Multiplexer (INPMUX) Register Field Descriptions
        4. 9.6.2.4  Gain Setting Register (address = 03h) [reset = 00h]
          1. Table 19. Gain Setting (PGA) Register Field Descriptions
        5. 9.6.2.5  Data Rate Register (address = 04h) [reset = 14h]
          1. Table 20. Data Rate (DATARATE) Register Field Descriptions
        6. 9.6.2.6  Reference Control Register (address = 05h) [reset = 10h]
          1. Table 21. Reference Control (REF) Register Field Descriptions
        7. 9.6.2.7  Excitation Current Register 1 (address = 06h) [reset = 00h]
          1. Table 22. Excitation Current Register 1 (IDACMAG) Register Field Descriptions
        8. 9.6.2.8  Excitation Current Register 2 (address = 07h) [reset = FFh]
          1. Table 23. Excitation Current Register 2 (IDACMUX) Register Field Descriptions
        9. 9.6.2.9  Sensor Biasing Register (address = 08h) [reset = 00h]
          1. Table 24. Sensor Biasing (VBIAS) Register Field Descriptions
        10. 9.6.2.10 System Control Register (address = 09h) [reset = 10h]
          1. Table 25. System Control (SYS) Register Field Descriptions
        11. 9.6.2.11 Reserved Register (address = 0Ah) [reset = 00h]
          1. Table 26. Reserved Register Field Descriptions
        12. 9.6.2.12 Offset Calibration Register 1 (address = 0Bh) [reset = 00h]
          1. Table 27. Offset Calibration Register 1 (OFCAL0) Register Field Descriptions
        13. 9.6.2.13 Offset Calibration Register 2 (address = 0Ch) [reset = 00h]
          1. Table 28. Offset Calibration Register 2 (OFCAL1) Register Field Descriptions
        14. 9.6.2.14 Reserved Register (address = 0Dh) [reset = 00h]
          1. Table 29. Reserved Register Field Descriptions
        15. 9.6.2.15 Gain Calibration Register 1 (address = 0Eh) [reset = 00h]
          1. Table 30. Gain Calibration Register 1 (FSCAL0) Field Descriptions
        16. 9.6.2.16 Gain Calibration Register 2 (address = 0Fh) [reset = 40h]
          1. Table 31. Gain Calibration Register 2 (FSCAL1) Field Descriptions
        17. 9.6.2.17 GPIO Data Register (address = 10h) [reset = 00h]
          1. Table 32. GPIO Data (GPIODAT) Register Field Descriptions
        18. 9.6.2.18 GPIO Configuration Register (address = 11h) [reset = 00h]
          1. Table 33. 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 What To Do and What Not To Do
  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

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RHB|32
  • PBS|32
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1 Noise Performance

Delta-sigma (ΔΣ) analog-to-digital converters (ADCs) are based on the principle of oversampling. The input signal of a ΔΣ ADC is sampled at a high frequency (modulator frequency) and subsequently filtered and decimated in the digital domain to yield a conversion result at the respective output data rate. The ratio between modulator frequency and output data rate is called the oversampling ratio (OSR). By increasing the OSR, and thus reducing the output data rate, the noise performance of the ADC can be optimized. In other words, the input-referred noise drops when reducing the output data rate because more samples of the internal modulator are averaged to yield one conversion result. Increasing the gain also reduces the input-referred noise, which is particularly useful when measuring low-level signals.

Table 1 and Table 2 summarize the device noise performance. Data are representative of typical noise performance at TA = 25°C using the internal 2.5-V reference. Data shown are based on 512 consecutive samples from a single device with inputs internally shorted. Table 1 lists the input-referred root mean square noise in units of μVRMS for the conditions shown. Peak-to-peak (µVPP) values are shown in parentheses. Table 2 lists the corresponding data in effective resolution calculated from μVRMS values using Equation 1. Noise-free resolution is calculated from µVPP values using Equation 2.

The input-referred noise (Table 1) only changes marginally when using an external low-noise reference, such as the REF5025. To calculate effective resolution and noise-free resolution when using a reference voltage other than 2.5 V, use Equation 1 and Equation 2:

Equation 1. Effective Resolution = ln[(2 · VREF / Gain) / VRMS-Noise] / ln(2)
Equation 2. Noise-Free Resolution= ln[(2 · VREF / Gain) / VPP-Noise] / ln(2)

Noise performance with the PGA bypassed are identical to the noise performance of the device with gain = 1.

Table 1. Noise in μVRMS (μVPP) at AVDD = 3.3 V, AVSS = 0 V,
PGA Enabled, and Internal 2.5-V Reference

DATA RATE
(SPS)		 GAIN
1 2 4 8 16 32 64 128
2.5 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
5 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
10 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
16.6 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
20 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
50 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.60)
60 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.2) 0.60 (0.90)
100 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.4) 0.60 (1.3)
200 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.4) 1.2 (1.9) 0.60 (1.7)
400 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (2.8) 1.2 (2.9) 0.60 (2.3)
800 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (4.0) 1.2 (3.8) 0.60 (3.2)
1000 76.3 (76.3) 38.1 (38.1) 19.1 (19.1) 9.5 (9.5) 4.8 (4.8) 2.4 (5.1) 1.2 (4.3) 0.60 (3.8)
2000 76.3 (83) 38.1 (80) 19.1 (32) 9.5 (17) 4.8 (11) 2.4 (6.7) 1.2 (6.6) 1.0 (6.5)
4000 103 (629) 38.1 (404) 24 (160) 12 (70) 6.4 (39) 3.3 (21) 3.1 (21) 2.6 (20)

Table 2. Effective Resolution From RMS Noise (Noise-Free Resolution From Peak-to-Peak Noise)
at AVDD = 3.3 V, AVSS = 0 V, PGA Enabled, and Internal 2.5-V Reference

DATA RATE
(SPS)		 GAIN
1 2 4 8 16 32 64 128
2.5 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
5 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
10 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
16.6 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
20 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16)
50 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.5)
60 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.4)
100 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.8) 16 (14.9)
200 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.3) 16 (14.5)
400 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.8) 16 (14.7) 16 (14.0)
800 16 (16) 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.2) 16 (14.3) 16 (13.6)
1000 16 (16) 16 (16) 16 (16) 16 (16) 16 (15.8) 16 (14.9) 16 (14.2) 16 (13.3)
2000 16 (15.9) 16 (14.9) 16 (15.3) 16 (15.2) 16 (14.8) 16 (14.5) 16 (13.5) 15.2 (12.6)
4000 16 (13.0) 16 (12.6) 15.7 (12.9) 16 (13.1) 15.6 (13.0) 15.5 (12.9) 14.4 (11.9) 13.6 (10.9)