SBAS661C February   2015  – May 2021 ADS1262 , ADS1263

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and 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: Serial Interface
    7. 7.7 Switching Characteristics: Serial Interface
    8. 7.8 Timing Diagrams
    9. 7.9 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Offset Temperature Drift Measurement
    2. 8.2 Gain Temperature Drift Measurement
    3. 8.3 Common-Mode Rejection Ratio Measurement
    4. 8.4 Power-Supply Rejection Ratio Measurement
    5. 8.5 Crosstalk Measurement (ADS1263)
    6. 8.6 Reference-Voltage Temperature-Drift Measurement
    7. 8.7 Reference-Voltage Thermal-Hysteresis Measurement
    8. 8.8 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  Multifunction Analog Inputs
      2. 9.3.2  Analog Input Description
        1. 9.3.2.1 ESD Diode
        2. 9.3.2.2 Input Multiplexer
      3. 9.3.3  Sensor Bias
      4. 9.3.4  Temperature Sensor
      5. 9.3.5  Power-Supply Monitor
      6. 9.3.6  PGA
      7. 9.3.7  PGA Voltage Overrange Monitors
        1. 9.3.7.1 PGA Differential Output Monitor
        2. 9.3.7.2 PGA Absolute Output-Voltage Monitor
      8. 9.3.8  ADC Reference Voltage
        1. 9.3.8.1 Internal Reference
        2. 9.3.8.2 External Reference
        3. 9.3.8.3 Power-Supply Reference
        4. 9.3.8.4 Low-Reference Monitor
      9. 9.3.9  ADC1 Modulator
      10. 9.3.10 Digital Filter
        1. 9.3.10.1 Sinc Filter Mode
          1. 9.3.10.1.1 Sinc Filter Frequency Response
        2. 9.3.10.2 FIR Filter
        3. 9.3.10.3 50-Hz and 60-Hz Line Cycle Rejection
      11. 9.3.11 Sensor-Excitation Current Sources (IDAC1 and IDAC2)
      12. 9.3.12 Level-Shift Voltage
      13. 9.3.13 General-Purpose Input/Output (GPIO)
      14. 9.3.14 Test DAC (TDAC)
      15. 9.3.15 ADC2 (ADS1263)
        1. 9.3.15.1 ADC2 Inputs
        2. 9.3.15.2 ADC2 PGA
        3. 9.3.15.3 ADC2 Reference
        4. 9.3.15.4 ADC2 Modulator
        5. 9.3.15.5 ADC2 Digital Filter
    4. 9.4 Device Functional Modes
      1. 9.4.1  Conversion Control
        1. 9.4.1.1 Continuous Conversion Mode
        2. 9.4.1.2 Pulse Conversion Mode
        3. 9.4.1.3 ADC2 Conversion Control (ADS1263)
      2. 9.4.2  Conversion Latency
      3. 9.4.3  Programmable Time Delay
      4. 9.4.4  Serial Interface
        1. 9.4.4.1 Chip Select (CS)
        2. 9.4.4.2 Serial Clock (SCLK)
        3. 9.4.4.3 Data Input (DIN)
        4. 9.4.4.4 Data Output/Data Ready (DOUT/DRDY)
        5. 9.4.4.5 Serial Interface Autoreset
      5. 9.4.5  Data Ready Pin (DRDY)
      6. 9.4.6  Conversion Data Software Polling
      7. 9.4.7  Read Conversion Data
        1. 9.4.7.1 Read Data Direct (ADC1 Only)
        2. 9.4.7.2 Read Data by Command
        3. 9.4.7.3 Data-Byte Sequence
          1. 9.4.7.3.1 Status Byte
          2. 9.4.7.3.2 Data Byte Format
          3. 9.4.7.3.3 Checksum Byte (CRC/CHK)
            1. 9.4.7.3.3.1 Checksum Mode (CRC[1:0] = 01h)
          4. 9.4.7.3.4 CRC Mode (CRC[1:0] = 10h)
      8. 9.4.8  ADC Clock Modes
        1. 9.4.8.1 Internal Oscillator
        2. 9.4.8.2 External Clock
        3. 9.4.8.3 Crystal Oscillator
      9. 9.4.9  Calibration
        1. 9.4.9.1 Offset and Full-Scale Calibration
          1. 9.4.9.1.1 Offset Calibration Registers
          2. 9.4.9.1.2 Full-Scale Calibration Registers
        2. 9.4.9.2 ADC1 Offset Self-Calibration (SFOCAL1)
        3. 9.4.9.3 ADC1 Offset System Calibration (SYOCAL1)
        4. 9.4.9.4 ADC2 Offset Self-Calibration ADC2 (SFOCAL2)
        5. 9.4.9.5 ADC2 Offset System Calibration ADC2 (SYOCAL2)
        6. 9.4.9.6 ADC1 Full-Scale System Calibration (SYGCAL1)
        7. 9.4.9.7 ADC2 Full-Scale System Calibration ADC2 (SYGCAL2)
        8. 9.4.9.8 Calibration Command Procedure
        9. 9.4.9.9 User Calibration Procedure
      10. 9.4.10 Reset
        1. 9.4.10.1 Power-On Reset (POR)
        2. 9.4.10.2 RESET/PWDN Pin
        3. 9.4.10.3 Reset by Command
      11. 9.4.11 Power-Down Mode
      12. 9.4.12 Chop Mode
    5. 9.5 Programming
      1. 9.5.1 NOP Command
      2. 9.5.2 RESET Command
      3. 9.5.3 START1, STOP1, START2, STOP2 Commands
      4. 9.5.4 RDATA1, RDATA2 Commands
      5. 9.5.5 SYOCAL1, SYGCAL1, SFOCAL1, SYOCAL2, SYGCAL2, SFOCAL2 Commands
      6. 9.5.6 RREG Command
      7. 9.5.7 WREG Command
    6. 9.6 Register Maps
      1. 9.6.1  Device Identification Register (address = 00h) [reset = x]
      2. 9.6.2  Power Register (address = 01h) [reset = 11h]
      3. 9.6.3  Interface Register (address = 02h) [reset = 05h]
      4. 9.6.4  Mode0 Register (address = 03h) [reset = 00h]
      5. 9.6.5  Mode1 Register (address = 04h) [reset = 80h]
      6. 9.6.6  Mode2 Register (address = 05h) [reset = 04h]
      7. 9.6.7  Input Multiplexer Register (address = 06h) [reset = 01h]
      8. 9.6.8  Offset Calibration Registers (address = 07h, 08h, 09h) [reset = 00h, 00h, 00h]
      9. 9.6.9  Full-Scale Calibration Registers (address = 0Ah, 0Bh, 0Ch) [reset = 40h, 00h, 00h]
      10. 9.6.10 IDACMUX Register (address = 0Dh) [reset = BBh]
      11. 9.6.11 IDACMAG Register (address = 0Eh) [reset = 00h]
      12. 9.6.12 REFMUX Register (address = 0Fh) [reset = 00h]
      13. 9.6.13 TDACP Control Register (address = 10h) [reset = 00h]
      14. 9.6.14 TDACN Control Register (address = 11h) [reset = 00h]
      15. 9.6.15 GPIO Connection Register (address = 12h) [reset = 00h]
      16. 9.6.16 GPIO Direction Register (address = 13h) [reset = 00h]
      17. 9.6.17 GPIO Data Register (address = 14h) [reset = 00h]
      18. 9.6.18 ADC2 Configuration Register (address = 15h) [reset = 00h]
      19. 9.6.19 ADC2 Input Multiplexer Register (address = 16h) [reset = 01h]
      20. 9.6.20 ADC2 Offset Calibration Registers (address = 17h, 18h) [reset = 00h, 00h]
      21. 9.6.21 ADC2 Full-Scale Calibration Registers (address = 19h, 1Ah) [reset = 00h, 40h]
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Isolated (or Floated) Inputs
      2. 10.1.2 Single-Ended Measurements
      3. 10.1.3 Differential Measurements
      4. 10.1.4 Input Range
      5. 10.1.5 Input Filtering
        1. 10.1.5.1 Aliasing
      6. 10.1.6 Input Overload
      7. 10.1.7 Unused Inputs and Outputs
      8. 10.1.8 Voltage Reference
      9. 10.1.9 Serial Interface Connections
    2. 10.2 Typical Application
      1. 10.2.1 3-Wire RTD Measurement with Lead-Wire Compensation
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curve
    3. 10.3 What To Do and What Not To Do
    4. 10.4 Initialization Setup
  11. 11Power Supply Recommendations
    1. 11.1 Power-Supply Decoupling
    2. 11.2 Analog Power-Supply Clamp
    3. 11.3 Power-Supply Sequencing
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Receiving Notification of Documentation Updates
    2. 13.2 Support Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary

Package Options

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

9.3.15.2 ADC2 PGA

ADC2 features a low-drift, low-noise CMOS PGA. The ADC2 PGA is bypassed for gains = 1, 2 and 4. Therefore, for these gains the input signal is connected directly to the buffered modulator input.

The full-scale voltage range of ADC2 is determined by the reference voltage and gain. Table 9-9 shows the ADC2 full-scale voltage range versus gain using reference voltage = 2.5 V. The full-scale voltage range scales with the reference voltage and is increased or decreased by changing the reference voltage.

Table 9-9 ADC2 Full-Scale Voltage Range
GAIN2[2:0] BITS
OF ADC2CFG REGISTER		GAIN (V/V)FULL-SCALE INPUT RANGE
(V)(1)
0001±2.500 V
0012±1.250 V
0104±0.625 V
0118±0.312 V
10016±0.156 V
10132±0.078 V
11064±0.039 V
111128±0.0195 V
(1) VREF = 2.5 V. The full-scale voltage range is proportional to VREF.

As with many amplifiers, do not exceed the PGA absolute input voltage requirement. For gains ≥ 8 (PGA active), the absolute input voltage is limited by the PGA output voltage swing range. The specified minimum and maximum absolute input voltages (VINP2 and VINN2) depend on the PGA gain, the input differential voltage (VIN2), and the tolerance of the analog power supply voltages (VAVDD, VAVSS). If using ADC2 in an overall gain ≥ 8, the absolute positive and negative input voltage must be within the specified range, as shown in Equation 15:

Equation 15. VAVSS + 0.3 + |VIN2| · (Gain – 1) / 2 · < VINP2 and VINN2 < VAVDD – 0.3 – |VIN2| · (Gain – 1) / 2

where

  • VINP2, VINN2 = ADC2 absolute input voltage
  • VIN2 = ADC2 differential input voltage = VINP2 - VINN2
  • Gain = 8, 16, 32, 64 or 128

For gains 1, 2, or 4, the ADC2 absolute input voltage range extends beyond the VAVDD and VAVSS supply voltages, allowing voltage inputs at or below ground. The absolute input voltage range corresponding to gains 1, 2 and 4 is shown in Equation 16:

Equation 16. VAVSS – 0.1 < VINP2 and VINN2 < VAVDD + 0.1