SBAS691B March   2016  – October 2018 ADS1282-SP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Description (continued)
  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  Pulse-Sync Timing Requirements
    8. 7.8  Reset Timing Requirements
    9. 7.9  Read Data Timing Requirements
    10. 7.10 Switching Characteristics
    11. 7.11 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Noise Performance
      2. 8.3.2  Input-Referred Noise
      3. 8.3.3  Idle Tones
      4. 8.3.4  Operating Mode
      5. 8.3.5  Analog Inputs and Multiplexer
      6. 8.3.6  PGA (Programmable Gain Amplifier)
      7. 8.3.7  ADC
      8. 8.3.8  Modulator
      9. 8.3.9  Modulator Over-Range
      10. 8.3.10 Modulator Input Impedance
      11. 8.3.11 Modulator Over-Range Detection (MFLAG)
      12. 8.3.12 Voltage Reference Inputs (VREFP, VREFN)
      13. 8.3.13 Digital Filter
        1. 8.3.13.1 Sinc Filter Stage (Sinx/X)
        2. 8.3.13.2 FIR Stage
        3. 8.3.13.3 Group Delay and Step Response
          1. 8.3.13.3.1 Linear Phase Response
          2. 8.3.13.3.2 Minimum Phase Response
        4. 8.3.13.4 HPF Stage
      14. 8.3.14 Master Clock Input (CLK)
      15. 8.3.15 Synchronization (SYNC Pin and Sync Command)
      16. 8.3.16 Pulse-Sync Mode
      17. 8.3.17 Continuous-Sync Mode
      18. 8.3.18 Reset (RESET Pin and Reset Command)
      19. 8.3.19 Power-Down (PWDN Pin and Standby Command)
      20. 8.3.20 Power-On Sequence
      21. 8.3.21 Serial Interface
        1. 8.3.21.1 Serial Clock (SCLK)
        2. 8.3.21.2 Data Input (DIN)
        3. 8.3.21.3 Data Output (DOUT)
        4. 8.3.21.4 Data Ready (DRDY)
      22. 8.3.22 Data Format
      23. 8.3.23 Reading Data
        1. 8.3.23.1 Read Data Continuous
        2. 8.3.23.2 Read Data by Command
      24. 8.3.24 One-Shot Operation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Modulator Output Mode
    5. 8.5 Programming
      1. 8.5.1 Commands
        1. 8.5.1.1  WAKEUP: Wake-Up from Standby Mode
        2. 8.5.1.2  STANDBY: Standby Mode
        3. 8.5.1.3  SYNC: Synchronize the A/D Conversion
        4. 8.5.1.4  RESET: Reset the Device
        5. 8.5.1.5  RDATAC: Read Data Continuous
        6. 8.5.1.6  SDATAC: Stop Read Data Continuous
        7. 8.5.1.7  RDATA: Read Data By Command
        8. 8.5.1.8  RREG: Read Register Data
        9. 8.5.1.9  WREG: Write to Register
        10. 8.5.1.10 OFSCAL: Offset Calibration
        11. 8.5.1.11 GANCAL: Gain Calibration
      2. 8.5.2 Calibration Commands
        1. 8.5.2.1 OFSCAL Command
        2. 8.5.2.2 GANCAL Command
      3. 8.5.3 User Calibration
      4. 8.5.4 Configuration Guide
    6. 8.6 Register Maps
      1. 8.6.1 ADS1282-SP Register Map Information
      2. 8.6.2 ID Register
        1. Table 13. ID Register Field Descriptions
      3. 8.6.3 Configuration Registers
        1. 8.6.3.1 Configuration Register 0
          1. Table 14. Configuration Register 0 Field Descriptions
        2. 8.6.3.2 Configuration Register 1
          1. Table 15. Configuration Register 1 Field Descriptions
      4. 8.6.4 HPF1 and HPF0
        1. 8.6.4.1 High-Pass Filter Corner Frequency, Low Byte
        2. 8.6.4.2 High-Pass Filter Corner Frequency, High Byte
      5. 8.6.5 OFC2, OFC1, OFC0
        1. 8.6.5.1 Offset Calibration, Low Byte
        2. 8.6.5.2 Offset Calibration, Mid Byte
        3. 8.6.5.3 Offset Calibration, High Byte
      6. 8.6.6 FSC2, FSC1, FSC0
        1. 8.6.6.1 Full-Scale Calibration, Low Byte
        2. 8.6.6.2 Full-Scale Calibration, Mid Byte
        3. 8.6.6.3 Full-Scale Calibration, High Byte
      7. 8.6.7 Offset and Full-Scale Calibration Registers
        1. 8.6.7.1 OFC[2:0] Registers
        2. 8.6.7.2 FSC[2:0] Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Thermocouple Temperature Sensing Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
      2. 9.2.2 Digital Connection to a Field Programmable Gate Array (FPGA) Device Typical Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 HPF Transfer Function
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community 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

8.3.12 Voltage Reference Inputs (VREFP, VREFN)

The voltage reference for the ADS1282-SP is the differential voltage between VREFP and VREFN: VREF = VREFP – VREFN. The reference inputs use a structure similar to that of the analog inputs with the circuitry of the reference inputs shown in Figure 35. The average load presented by the switched capacitor reference input can be modeled with an effective differential impedance of REFF = tSAMPLE / CIN (tSAMPLE = 1/ƒMOD). The effective impedance of the reference inputs loads the external reference.

ADS1282-SP ai_ref_in_cir_bas418.gifFigure 35. Simplified Reference Input Circuit

The ADS1282-SP reference inputs are protected by ESD diodes. In order to prevent these diodes from turning on, the voltage on either input must stay within the range shown in Equation 7:

Equation 7. AVSS – 300 mV < (VREFP or VREFN) < AVDD + 300 mV

The minimum valid input for VREFN is AVSS – 0.1 V and maximum valid input for VREFP is AVDD + 0.1 V.

A high-quality 5 V reference voltage is necessary for achieving the best performance from the ADS1282-SP. Noise and drift on the reference degrade overall system performance, and it is critical that special care be given to the circuitry generating the reference voltages in order to achieve full performance. See Application Information for reference recommendations.