SBAS751B October   2017  – October 2018 ADS122C04

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      K-Type Thermocouple Measurement
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 I2C Timing Requirements
    7. 6.7 I2C Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Noise Performance
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Multiplexer
      2. 8.3.2  Low-Noise Programmable Gain Stage
        1. 8.3.2.1 PGA Input Voltage Requirements
        2. 8.3.2.2 Bypassing the PGA
      3. 8.3.3  Voltage Reference
      4. 8.3.4  Modulator and Internal Oscillator
      5. 8.3.5  Digital Filter
      6. 8.3.6  Conversion Times
      7. 8.3.7  Excitation Current Sources
      8. 8.3.8  Sensor Detection
      9. 8.3.9  System Monitor
      10. 8.3.10 Temperature Sensor
        1. 8.3.10.1 Converting From Temperature to Digital Codes
          1. 8.3.10.1.1 For Positive Temperatures (For Example, 50°C):
          2. 8.3.10.1.2 For Negative Temperatures (For Example, –25°C):
        2. 8.3.10.2 Converting From Digital Codes to Temperature
      11. 8.3.11 Offset Calibration
      12. 8.3.12 Conversion Data Counter
      13. 8.3.13 Data Integrity Features
    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 RESET Pin
        3. 8.4.1.3 Reset by Command
      2. 8.4.2 Conversion Modes
        1. 8.4.2.1 Single-Shot Conversion Mode
        2. 8.4.2.2 Continuous Conversion Mode
      3. 8.4.3 Operating Modes
        1. 8.4.3.1 Normal Mode
        2. 8.4.3.2 Turbo Mode
        3. 8.4.3.3 Power-Down Mode
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
        1. 8.5.1.1 I2C Address
        2. 8.5.1.2 Serial Clock (SCL) and Serial Data (SDA)
        3. 8.5.1.3 Data Ready (DRDY)
        4. 8.5.1.4 Interface Speed
        5. 8.5.1.5 Data Transfer Protocol
        6. 8.5.1.6 I2C General Call (Software Reset)
        7. 8.5.1.7 Timeout
      2. 8.5.2 Data Format
      3. 8.5.3 Commands
        1. 8.5.3.1 Command Latching
        2. 8.5.3.2 RESET (0000 011x)
        3. 8.5.3.3 START/SYNC (0000 100x)
        4. 8.5.3.4 POWERDOWN (0000 001x)
        5. 8.5.3.5 RDATA (0001 xxxx)
        6. 8.5.3.6 RREG (0010 rrxx)
        7. 8.5.3.7 WREG (0100 rrxx dddd dddd)
      4. 8.5.4 Reading Data and Monitoring for New Conversion Results
      5. 8.5.5 Data Integrity
    6. 8.6 Register Map
      1. 8.6.1 Configuration Registers
      2. 8.6.2 Register Descriptions
        1. 8.6.2.1 Configuration Register 0 (address = 00h) [reset = 00h]
          1. Table 19. Configuration Register 0 Field Descriptions
        2. 8.6.2.2 Configuration Register 1 (address = 01h) [reset = 00h]
          1. Table 20. Configuration Register 1 Field Descriptions
        3. 8.6.2.3 Configuration Register 2 (address = 02h) [reset = 00h]
          1. Table 22. Configuration Register 2 Field Descriptions
        4. 8.6.2.4 Configuration Register 3 (address = 03h) [reset = 00h]
          1. Table 23. Configuration Register 3 Field Descriptions
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Interface Connections
      2. 9.1.2 Connecting Multiple Devices on the Same I2C Bus
      3. 9.1.3 Unused Inputs and Outputs
      4. 9.1.4 Analog Input Filtering
      5. 9.1.5 External Reference and Ratiometric Measurements
      6. 9.1.6 Establishing Proper Limits on the Absolute Input Voltage
      7. 9.1.7 Pseudo Code Example
    2. 9.2 Typical Applications
      1. 9.2.1 K-Type Thermocouple Measurement (–200°C to +1250°C)
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 3-Wire RTD Measurement (–200°C to +850°C)
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Design Variations for 2-Wire and 4-Wire RTD Measurements
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Resistive Bridge Measurement
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
  10. 10Power Supply Recommendations
    1. 10.1 Power-Supply Sequencing
    2. 10.2 Power-Supply Decoupling
  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 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

6.6 I2C Timing Requirements

over operating ambient temperature range and DVDD = 2.3 V to 5.5 V, bus capacitance = 10 pF to 400 pF, and pullup resistor = 1 kΩ (unless otherwise noted)
MIN MAX UNIT
STANDARD-MODE
fSCL SCL clock frequency 0 100 kHz
tHD;STA Hold time, (repeated) START condition.
After this period, the first clock pulse is generated.		 4 µs
tLOW Pulse duration, SCL low 4.7 µs
tHIGH Pulse duration, SCL high 4.0 µs
tSU;STA Setup time, repeated START condition 4.7 µs
tHD;DAT Hold time, data 0 µs
tSU;DAT Setup time, data 250 ns
tr Rise time, SCL, SDA 1000 ns
tf Fall time, SCL, SDA 250 ns
tSU;STO Setup time, STOP condition 4.0 µs
tBUF Bus free time, between STOP and START condition 4.7 µs
tVD;DAT Valid time, data 3.45 µs
tVD;ACK Valid time, acknowledge 3.45 µs
FAST-MODE
fSCL SCL clock frequency 0 400 kHz
tHD;STA Hold time, (repeated) START condition.
After this period, the first clock pulse is generated.		 0.6 µs
tLOW Pulse duration, SCL low 1.3 µs
tHIGH Pulse duration, SCL high 0.6 µs
tSU;STA Setup time, repeated START condition 0.6 µs
tHD;DAT Hold time, data 0 µs
tSU;DAT Setup time, data 100 ns
tr Rise time, SCL, SDA 20 300 ns
tf Fall time, SCL, SDA 20 · (DVDD / 5.5 V) 250 ns
tSU;STO Setup time, STOP condition 0.6 µs
tBUF Bus free time, between STOP and START condition 1.3 µs
tVD;DAT Valid time, data 0.9 µs
tVD;ACK Valid time, acknowledge 0.9 µs
tSP Pulse width of spikes that must be suppressed by the input filter 0 50 ns
FAST-MODE PLUS
fSCL SCL clock frequency 0 1000 kHz
tHD;STA Hold time, (repeated) START condition.
After this period, the first clock pulse is generated.		 0.26 µs
tLOW Pulse duration, SCL low 0.5 µs
tHIGH Pulse duration, SCL high 0.26 µs
tSU;STA Setup time, repeated START condition 0.26 µs
tHD;DAT Hold time, data 0 µs
tSU;DAT Setup time, data 50 ns
tr Rise time, SCL, SDA 120 ns
tf Fall time, SCL, SDA Pullup resistor = 350 Ω 20 · (DVDD / 5.5 V) 120 ns
tSU;STO Setup time, STOP condition 0.26 µs
tBUF Bus free time, between STOP and START condition 0.5 µs
tVD;DAT Valid time, data 0.45 µs
tVD;ACK Valid time, acknowledge 0.45 µs
tSP Pulse duration of spikes that must be suppressed by the input filter 0 50 ns
RESET PIN
tw(RSL) Pulse duration, RESET low 250 ns
td(RSSTA) Delay time, START condition after RESET rising edge(2) 100 ns
DRDY PIN
td(DRSTA) Delay time, START condition after DRDY falling edge 0 ns
TIMEOUT
Timeout(1) Normal mode 14000 tMOD
Turbo mode 28000
(1) See the Timeout section for more information.
tMOD = 1 / fMOD. Modulator frequency fMOD = 256 kHz (normal mode) and 512 kHz (turbo mode).
(2) No delay time is required when using the RESET command as long as all I2C timing requirements for the (repeated) START and STOP conditions are met.