SBASAF2 August   2022 ADS131M06-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Noise Measurements
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Input ESD Protection Circuitry
      2. 8.3.2  Input Multiplexer
      3. 8.3.3  Programmable Gain Amplifier (PGA)
      4. 8.3.4  Voltage Reference
      5. 8.3.5  Clocking and Power Modes
      6. 8.3.6  ΔΣ Modulator
      7. 8.3.7  Digital Filter
        1. 8.3.7.1 Digital Filter Implementation
          1. 8.3.7.1.1 Fast-Settling Filter
          2. 8.3.7.1.2 SINC3 and SINC3 + SINC1 Filter
        2. 8.3.7.2 Digital Filter Characteristic
      8. 8.3.8  DC Block Filter
      9. 8.3.9  Internal Test Signals
      10. 8.3.10 Channel Phase Calibration
      11. 8.3.11 Calibration Registers
      12. 8.3.12 Communication Cyclic Redundancy Check (CRC)
      13. 8.3.13 Register Map CRC
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Up and Reset
        1. 8.4.1.1 Power-On Reset
        2. 8.4.1.2 SYNC/RESET Pin
        3. 8.4.1.3 RESET Command
      2. 8.4.2 Fast Start-Up Behavior
      3. 8.4.3 Conversion Modes
        1. 8.4.3.1 Continuous-Conversion Mode
        2. 8.4.3.2 Global-Chop Mode
      4. 8.4.4 Power Modes
      5. 8.4.5 Standby Mode
      6. 8.4.6 Current-Detect Mode
    5. 8.5 Programming
      1. 8.5.1 Interface
        1. 8.5.1.1  Chip Select (CS)
        2. 8.5.1.2  Serial Data Clock (SCLK)
        3. 8.5.1.3  Serial Data Input (DIN)
        4. 8.5.1.4  Serial Data Output (DOUT)
        5. 8.5.1.5  Data Ready (DRDY)
        6. 8.5.1.6  Conversion Synchronization or System Reset (SYNC/RESET)
        7. 8.5.1.7  SPI Communication Frames
        8. 8.5.1.8  SPI Communication Words
        9. 8.5.1.9  ADC Conversion Data
          1. 8.5.1.9.1 Collecting Data for the First Time or After a Pause in Data Collection
        10. 8.5.1.10 Commands
          1. 8.5.1.10.1 NULL (0000 0000 0000 0000)
          2. 8.5.1.10.2 RESET (0000 0000 0001 0001)
          3. 8.5.1.10.3 STANDBY (0000 0000 0010 0010)
          4. 8.5.1.10.4 WAKEUP (0000 0000 0011 0011)
          5. 8.5.1.10.5 LOCK (0000 0101 0101 0101)
          6. 8.5.1.10.6 UNLOCK (0000 0110 0101 0101)
          7. 8.5.1.10.7 RREG (101a aaaa annn nnnn)
            1. 8.5.1.10.7.1 Reading a Single Register
            2. 8.5.1.10.7.2 Reading Multiple Registers
          8. 8.5.1.10.8 WREG (011a aaaa annn nnnn)
        11. 8.5.1.11 Short SPI Frames
      2. 8.5.2 Synchronization
    6. 8.6 Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Unused Inputs and Outputs
      2. 9.1.2 Antialiasing
      3. 9.1.3 Minimum Interface Connections
      4. 9.1.4 Multiple Device Configuration
      5. 9.1.5 Troubleshooting
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Current Shunt Measurement
        2. 9.2.2.2 Battery Pack Voltage Measurement
      3. 9.2.3 Application Curve
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 CAP Pin Behavior
      2. 9.3.2 Power-Supply Sequencing
      3. 9.3.3 Power-Supply Decoupling
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 Programmable Gain Amplifier (PGA)

Each channel of the ADS131M06-Q1 features an integrated programmable gain amplifier (PGA) that provides gains of 1, 2, 4, 8, 16, 32, 64, and 128. The gains for all channels are individually controlled by the PGAGAINn bits for each channel in the GAIN1 register.

Varying the PGA gain scales the differential full-scale input voltage range (FSR) of the ADC. Equation 3 describes the relationship between FSR and gain. Equation 3 uses the internal reference voltage, 1.2 V, as the scaling factor without accounting for gain error caused by tolerance in the reference voltage.

Equation 3. FSR = ±1.2 V / Gain

Table 8-1 shows the corresponding full-scale ranges for each gain setting, assuming the internal reference is used.

Table 8-1 Full-Scale Range
GAIN SETTING FSR
1 ±1.2 V
2 ±600 mV
4 ±300 mV
8 ±150 mV
16 ±75 mV
32 ±37.5 mV
64 ±18.75 mV
128 ±9.375 mV

The input impedance of the PGA dominates the input impedance characteristics of the ADS131M06-Q1. The PGA input impedance for gain settings up to 4 behaves according to Equation 4 without accounting for device tolerance and change over temperature. Minimize the output impedance of the circuit that drives the ADS131M06-Q1 inputs to obtain the best possible gain error, INL, and distortion performance.

Equation 4. 330 kΩ × 4.096 MHz / fMOD

where:

  • fMOD is the ΔΣ modulator frequency, fCLKIN / 2

The device uses an input precharge buffer for PGA gain settings of 8 and higher. The input impedance at these gain settings is very high. Specifying the input bias current for these gain settings is therefore more useful. A plot of input bias current for the high gain settings is provided in Figure 6-5.