SBAS950B October   2019  – February 2021 ADS131M08

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 Startup 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 0110 0110)
          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 Power Metrology Applications
      5. 9.1.5 Multiple Device Configuration
      6. 9.1.6 Code Example
      7. 9.1.7 Troubleshooting
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Voltage Measurement Front-End
        2. 9.2.2.2 Current Measurement Front-End
        3. 9.2.2.3 ADC Setup
        4. 9.2.2.4 Calibration
        5. 9.2.2.5 Formulae
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 CAP Pin Behavior
    2. 10.2 Power-Supply Sequencing
    3. 10.3 Power-Supply Decoupling
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

6.5 Electrical Characteristics

minimum and maximum specifications apply from TA = –40°C to +125°C; typical specifications are at TA = 25°C; all specifications are at AVDD = 3 V, DVDD = 3 V, fCLKIN = 8.192 MHz, data rate = 4 kSPS, gain = 1, all channels enabled, global-chop mode disabled, using internal reference with 100-nF tied to REFIN pin, and internal oscillator disabled (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG INPUTS
Zin Differential input impedance Gain = 1, 2, or 4 330 kΩ
Ib Input bias current Gain = 8, 16, 32, 64, or 128, inputs shorted to ground ±1 µA/V
ADC CHARACTERISTICS
Resolution 24 Bits
Gain settings 1, 2, 4, 8, 16, 32, 64, 128
fDATA Data rate High-resolution mode, fCLKIN = 8.192 MHz 250 32k SPS
Low-power mode, fCLKIN = 4.096 MHz 125 16k
Very low-power mode, fCLKIN = 2.048 MHz 62.5 8k
Startup time Measured from supplies at 90% to first DRDY falling edge 0.5 ms
ADC PERFORMANCE
INL Integral nonlinearity (best fit) 7.5 ppm of FSR
Offset error (input referred) ±240 µV
Global-chop mode ±32
Offset drift 215 nV/°C
Global-chop mode 105
Gain error ±0.3%
Gain drift Excluding voltage reference error, gain = 1 5 ppm/°C
Including internal voltage reference error, gain = 1 10 20
Including internal voltage reference error, gain = 32 15
Long-term gain drift 1000 hours at 85°C, including internal voltage reference error, TQFP package 385 ppm
1000 hours at 85°C, including internal voltage reference error, WQFN package  90
CMRR Common-mode rejection ratio At dc 100 dB
fCM = 50 Hz or 60 Hz 94
PSRR Power-supply rejection ratio AVDD at DC 80 dB
DVDD at DC 100
AVDD supply, fPS = 50 Hz or 60 Hz 78
DVDD supply, fPS = 50 Hz or 60 Hz 90
Input referred noise 5.4 µVRMS
During fast startup 1500
Dynamic range Gain = 1 99 102 dB
Gain = 64 80
All other gain settings See Table 7-1
Crosstalk fIN = 50 Hz or 60 Hz –120 dB
SNR Signal-to-noise ratio fIN = 50 Hz or 60 Hz, gain = 1,
VIN = –0.5 dBFS, normalized		 101 dB
fIN = 50 Hz or 60 Hz, gain = 64,
VIN = –0.5 dBFS, normalized		 80
THD Total harmonic distortion fIN = 50 Hz or 60 Hz (up to 50 harmonics),
VIN = –0.5 dBFS		 –100 dB
SFDR Spurious-free dynamic range fIN = 50 Hz or 60 Hz (up to 50 harmonics),
VIN = –0.5 dBFS		 103 dB
INTERNAL VOLTAGE REFERENCE
VREF Internal reference voltage 1.2 V
Accuracy TA = 25°C ±0.1%
Temperature drift 8 20 ppm/°C
Long-term reference drift 1000 hours at 85°C, TQFP package 340 ppm
1000 hours at 85°C, WQFN package 70 
DIGITAL INPUTS/OUTPUTS
VIL Logic input level, low DGND 0.2 DVDD V
VIH Logic input level, high 0.8 DVDD DVDD V
VOL Logic output level, low IOL = –1 mA 0.2 DVDD V
VOH Logic output level, high IOH = 1 mA 0.8 DVDD V
IIN Input current DGND < VDigital Input < DVDD –1 1 µA
POWER SUPPLY
IAVDD Analog supply current High-resolution mode 6.5 7.7 mA
Low-power mode 3.4 4.1
Very low-power mode 1.9 2.3
Current-detect mode 1.8
Standby mode 0.35 µA
IDVDD Digital supply current(1) High-resolution mode 0.66 0.9 mA
Low-power mode 0.35 0.47
Very low-power mode 0.18 0.3
Current-detect mode 0.115
Standby mode 1.1 µA
PD Power dissipation High-resolution mode 21.5 mW
Low-power mode 11.3
Very low-power mode 6.2
Current-detect mode 5.8
Standby mode 4.4 µW
(1) Currents measured with SPI idle and oscillator disabled.