SBAS511E july   2010  – july 2023 ADS1013-Q1 , ADS1014-Q1 , ADS1015-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6.   Device Comparison Table
  7. 5 Pin Configuration and Functions
  8. 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: I2C
    7. 6.7 Timing Diagram
    8. 6.8 Typical Characteristics
  9. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Multiplexer
      2. 7.3.2 Analog Inputs
      3. 7.3.3 Full-Scale Range (FSR) and LSB Size
      4. 7.3.4 Voltage Reference
      5. 7.3.5 Oscillator
      6. 7.3.6 Output Data Rate and Conversion Time
      7. 7.3.7 Digital Comparator (ADS1014-Q1 and ADS1015-Q1 Only)
      8. 7.3.8 Conversion Ready Pin (ADS1014-Q1 and ADS1015-Q1 Only)
      9. 7.3.9 SMbus Alert Response
    4. 7.4 Device Functional Modes
      1. 7.4.1 Reset and Power-Up
      2. 7.4.2 Operating Modes
        1. 7.4.2.1 Single-Shot Mode
        2. 7.4.2.2 Continuous-Conversion Mode
      3. 7.4.3 Duty Cycling For Low Power
    5. 7.5 Programming
      1. 7.5.1 I2C Interface
        1. 7.5.1.1 I2C Address Selection
        2. 7.5.1.2 I2C General Call
        3. 7.5.1.3 I2C Speed Modes
      2. 7.5.2 Target Mode Operations
        1. 7.5.2.1 Receive Mode
        2. 7.5.2.2 Transmit Mode
      3. 7.5.3 Writing To and Reading From the Registers
      4. 7.5.4 Data Format
    6. 7.6 Register Map
      1. 7.6.1 Address Pointer Register (address = N/A) [reset = N/A]
      2. 7.6.2 Conversion Register (P[1:0] = 00b) [reset = 0000h]
      3. 7.6.3 Config Register (P[1:0] = 01b) [reset = 8583h]
      4. 7.6.4 Lo_thresh (P[1:0] = 10b) [reset = 8000h] and Hi_thresh (P[1:0] = 11b) [reset = 7FFFh] Registers
  10. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Basic Connections
      2. 8.1.2 Single-Ended Inputs
      3. 8.1.3 Input Protection
      4. 8.1.4 Unused Inputs and Outputs
      5. 8.1.5 Analog Input Filtering
      6. 8.1.6 Connecting Multiple Devices
      7. 8.1.7 Quick-Start Guide
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Shunt Resistor Considerations
        2. 8.2.2.2 Operational Amplifier Considerations
        3. 8.2.2.3 ADC Input Common-Mode Considerations
        4. 8.2.2.4 Resistor (R1, R2, R3, R4) Considerations
        5. 8.2.2.5 Noise and Input Impedance Considerations
        6. 8.2.2.6 First-Order RC Filter Considerations
        7. 8.2.2.7 Circuit Implementation
        8. 8.2.2.8 Results Summary
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power-Supply Sequencing
      2. 8.3.2 Power-Supply Decoupling
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  11. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  12. 10Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.5 Noise and Input Impedance Considerations

If vn_res represents the input-referred rms noise from all the resistors, vn_op represents the input-referred rms noise of the OPA333-Q1, and vn_ADC represents the input-referred rms noise of the ADS1015-Q1, the total input-referred noise of the entire system, vN, can be approximated by Equation 11.

Equation 11. vN2 = vn_res2 + vn_op2 + vn_ADC/ (1 + R2 / R1)2

The ADC noise contribution, vn_ADC, is attenuated by the noninverting gain stage.

If the gain of the noninverting gain stage is high (≥ 5), a good approximation for vn_res2 is given by Equation 12. The noise contribution from resistors R2, R4, R5, and R6 when referred to the input is smaller in comparison to R1 and R3 and can be neglected for approximation purposes.

Equation 12. vn_res2 = 4 · k · T · (R1 + R3) · Δf

where

  • k = Boltzmann constant
  • T = Temperature (in kelvins)
  • Δf = Noise bandwidth

An approximation for the input impedance, RIN, of the application circuit is given by Equation 13. RIN can be modeled as a resistor in parallel with the shunt resistor, and can contribute to additional gain error.

Equation 13. RIN = R3 + R4

From Equation 12 and Equation 13, a trade-off exists between vN and RIN. If R3 increases, vn_res increases, and therefore, the total input-referred rms system noise, vN, increases. If R3 decreases, the input impedance, RIN, drops, and causes additional gain error.