SBOSAE0B April   2023  – September 2023 PGA855

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Gain Control
      2. 8.3.2 Input Protection
      3. 8.3.3 Output Common-Mode Pin
      4. 8.3.4 Using the Fully Differential Output Amplifier to Shape Noise
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Linear Operating Input Range
    2. 9.2 Typical Applications
      1. 9.2.1 ADS127L11 and ADS127L21, 24-Bit, Delta-Sigma ADC Driver Circuit
        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 ADS8900B 20-Bit SAR ADC Driver Circuit
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 PSpice® for TI
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.1.1 Design Requirements

The design requirements for the application driving the ADS127Lx1 ADC are listed in the following table.

Table 9-1 Design Parameters
PARAMETER VALUE
Differential-to-differential conversion VINDIFF to VOUTDIFF
Supply voltages VS± = ±15 V, VLVDD = 5 V, VLVSS = GND, VREF = 4.096 V
Full-scale range of ADC FSR = ± 4.096 V
Data rate of ADC fDATA = 187.5 kSPS
ADC filter configuration (1) High-speed mode, Sinc4 filter, OSR = 64
(2) High-speed mode, Wideband filter, OSR = 64
PGA gain See Table 9-2 and Table 9-3
Signal frequency Tested at fIN = 1 kHz
RC kickback filter(1) RFIL = 47.4 Ω, CDIFF = 560 pF, CCM = 51 pF
(1) Consider a trade-off between THD, frequency response, and drift. The differential current drift into the ADC can interact with the filter resistors and result in higher drift errors. However, lower resistance degrades the phase margin of the PGA855. For low drift applications, keep RFIL < 50 Ω.