SBAS563E December   2011  – December 2022 ADS1113-Q1 , ADS1114-Q1 , ADS1115-Q1

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
    1.     Device Comparison Table
  5. Pin Configuration and Functions
  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
  7. Parameter Measurement Information
    1. 7.1 Noise Performance
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Multiplexer
      2. 8.3.2 Analog Inputs
      3. 8.3.3 Full-Scale Range (FSR) and LSB Size
      4. 8.3.4 Voltage Reference
      5. 8.3.5 Oscillator
      6. 8.3.6 Output Data Rate and Conversion Time
      7. 8.3.7 Digital Comparator (ADS1114-Q1 and ADS1115-Q1 Only)
      8. 8.3.8 Conversion Ready Pin (ADS1114-Q1 and ADS1115-Q1 Only)
      9. 8.3.9 SMbus Alert Response
    4. 8.4 Device Functional Modes
      1. 8.4.1 Reset and Power-Up
      2. 8.4.2 Operating Modes
        1. 8.4.2.1 Single-Shot Mode
        2. 8.4.2.2 Continuous-Conversion Mode
      3. 8.4.3 Duty Cycling For Low Power
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
        1. 8.5.1.1 I2C Address Selection
        2. 8.5.1.2 I2C General Call
        3. 8.5.1.3 I2C Speed Modes
      2. 8.5.2 Target Mode Operations
        1. 8.5.2.1 Receive Mode
        2. 8.5.2.2 Transmit Mode
      3. 8.5.3 Writing To and Reading From the Registers
      4. 8.5.4 Data Format
    6. 8.6 Register Map
      1. 8.6.1 Address Pointer Register (address = N/A) [reset = N/A]
      2. 8.6.2 Conversion Register (P[1:0] = 00b) [reset = 0000h]
      3. 8.6.3 Config Register (P[1:0] = 01b) [reset = 8583h]
      4. 8.6.4 Lo_thresh (P[1:0] = 10b) [reset = 8000h] and Hi_thresh (P[1:0] = 11b) [reset = 7FFFh] Registers
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Basic Connections
      2. 9.1.2 Single-Ended Inputs
      3. 9.1.3 Input Protection
      4. 9.1.4 Unused Inputs and Outputs
      5. 9.1.5 Analog Input Filtering
      6. 9.1.6 Connecting Multiple Devices
      7. 9.1.7 Quick-Start Guide
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Shunt Resistor Considerations
        2. 9.2.2.2 Operational Amplifier Considerations
        3. 9.2.2.3 ADC Input Common-Mode Considerations
        4. 9.2.2.4 Resistor (R1, R2, R3, R4) Considerations
        5. 9.2.2.5 Noise and Input Impedance Considerations
        6. 9.2.2.6 First-Order RC Filter Considerations
        7. 9.2.2.7 Circuit Implementation
        8. 9.2.2.8 Results Summary
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Power-Supply Sequencing
      2. 9.3.2 Power-Supply Decoupling
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

Layout Guidelines

Employ best design practices when laying out a printed-circuit board (PCB) for both analog and digital components. For optimal performance, separate the analog components [such as ADCs, amplifiers, references, digital-to-analog converters (DACs), and analog MUXs] from digital components [such as microcontrollers, complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), radio frequency (RF) transceivers, universal serial bus (USB) transceivers, and switching regulators]. An example of good component placement is shown in Figure 9-10. Although Figure 9-10 provides a good example of component placement, the best placement for each application is unique to the geometries, components, and PCB fabrication capabilities employed. That is, there is no single layout that is perfect for every design and careful consideration must always be used when designing with any analog component.

GUID-8E1E43C1-3602-4EF2-AD70-46B3BF8B0575-low.gifFigure 9-10 System Component Placement

The following outlines some basic recommendations for the layout of the ADS111x-Q1 to get the best possible performance of the ADC. A good design can be ruined with a bad circuit layout.

  • Separate analog and digital signals. To start, partition the board into analog and digital sections where the layout permits. Route digital lines away from analog lines. This architecture prevents digital noise from coupling back into analog signals.
  • Fill void areas on signal layers with ground fill.
  • Provide good ground return paths. Signal return currents flow on the path of least impedance. If the ground plane is cut or has other traces that block the current from flowing right next to the signal trace, the current must find another path to return to the source and complete the circuit. If the current is forced into a larger path, longer route increases the chance that the signal radiates. Sensitive signals are more susceptible to EMI interference.
  • Use bypass capacitors on supplies to reduce high-frequency noise. Do not place vias between bypass capacitors and the active device. Placing the bypass capacitors on the same layer as close to the active device yields the best results.
  • Consider the resistance and inductance of the routing. Often, traces for the inputs have resistances that react with the input bias current and cause an added error voltage. Reduce the loop area enclosed by the source signal and the return current in order to reduce the inductance in the path. Reduce the inductance to reduce the EMI pickup, and reduce the high frequency impedance observed by the device.
  • Differential inputs must be matched for both the inputs going to the measurement source.
  • Analog inputs with differential connections must have a capacitor placed differentially across the inputs. Best input combinations for differential measurements use adjacent analog input lines such as AIN0, AIN1 and AIN2, AIN3. The differential capacitors must be of high quality. The best ceramic chip capacitors are C0G (NPO), which have stable properties and low-noise characteristics.