SBASAD1A December   2023  – May 2024 ADC3910D025 , ADC3910D065 , ADC3910D125 , ADC3910S025 , ADC3910S065 , ADC3910S125

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics - Power Consumption
    6. 5.6  Electrical Characteristics - DC Specifications
    7. 5.7  Electrical Characteristics - AC Specifications (25 MSPS)
    8. 5.8  Electrical Characteristics - AC Specifications (65 MSPS)
    9. 5.9  Electrical Characteristics - AC Specifications (125 MSPS)
    10. 5.10 Timing Requirements
    11. 5.11 Output Interface Timing Diagram
    12. 5.12 Typical Characteristics - 25MSPS
    13. 5.13 Typical Characteristics - 65MSPS
    14. 5.14 Typical Characteristics - 125MSPS
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 ADC Features
        1. 6.3.1.1 Low Latency Mode
        2. 6.3.1.2 Full Digital Feature Mode
        3. 6.3.1.3 Interleaving Mode
      2. 6.3.2 Analog Input
        1. 6.3.2.1 Single Ended Input
        2. 6.3.2.2 Differential Input
        3. 6.3.2.3 Analog Input Bandwidth
      3. 6.3.3 Sampling Clock Input
      4. 6.3.4 Voltage Reference
      5. 6.3.5 Over-range (OVR)
      6. 6.3.6 Digital Features
        1. 6.3.6.1 Digital Down Converter
          1. 6.3.6.1.1 Digital Down Converter Data Select
          2. 6.3.6.1.2 Decimation Filter
          3. 6.3.6.1.3 DDC Over-range
          4. 6.3.6.1.4 Output Formatting with Decimation
        2. 6.3.6.2 Digital Comparator
          1. 6.3.6.2.1 Comparator Data Select
          2. 6.3.6.2.2 Comparator High and Low Threshold
          3. 6.3.6.2.3 Comparator Configuration Compare Mode
          4. 6.3.6.2.4 Comparator Event Configuration
        3. 6.3.6.3 Statistics Engine
          1. 6.3.6.3.1 Statistics Engine Data Select
          2. 6.3.6.3.2 Window Configuration
        4. 6.3.6.4 Digital Alerts
      7. 6.3.7 Digital Interface
        1. 6.3.7.1 Parallel CMOS Output
        2. 6.3.7.2 Serialized CMOS Output
      8. 6.3.8 Test Patterns
        1. 6.3.8.1 Bypass Test Pattern
        2. 6.3.8.2 Digital Test Pattern
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Power Down Options
    5. 6.5 Programming
      1. 6.5.1 Configuration using the SPI interface
        1. 6.5.1.1 Register Write
        2. 6.5.1.2 Register Read
    6. 6.6 Register Maps
      1. 6.6.1 Register Descriptions
      2. 6.6.2 Statistics Engine Register Map
      3. 6.6.3 Alerts Register Map
  8. 7 Application Information Disclaimer
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input Signal Path
        2. 7.2.2.2 Sampling Clock
        3. 7.2.2.3 Voltage Reference
      3. 7.2.3 Application Curves
    3. 7.3 Initialization Set Up
      1. 7.3.1 Register Initialization During Operation
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.4 Power Supply Recommendations

The ADC requires two different power-supplies. The AVDD rail provides power for the internal analog and digital circuits and the ADC itself while the IOVDD rail powers the digital interface. Power sequencing is not required.

The AVDD power supply must be low noise to achieve data sheet performance. In applications operating near DC, the 1/f noise contribution of the power supply also needs to be considered. The ADC is designed for very good PSRR which aids with the power supply filter design.

ADC3910D025 ADC3910D065 ADC3910D125 ADC3910S025 ADC3910S065 ADC3910S125 Power supply rejection ratio (PSRR) vs frequency
Figure 7-4 Power supply rejection ratio (PSRR) vs frequency

There are two recommended power-supply architectures:

  1. Step down using high-efficiency switching converters, followed by a second stage of regulation using a low noise LDO to provide switching noise reduction and improved voltage accuracy.
  2. Directly step down the final ADC supply voltage using high-efficiency switching converters. This approach provides the best efficiency, but care must be taken to make sure switching noise is minimized to prevent degraded ADC performance.

TI WEBENCH® Power Designer can be used to select and design the individual power-supply elements needed: see the WEBENCH® Power Designer

Recommended switching regulators for the first stage include the TPS62821, and similar devices.

Recommended low dropout (LDO) linear regulators include the TPS7A4701, TPS7A90, LP5901, and similar devices.

For the switch regulator only approach, the ripple filter must be designed with a notch frequency that aligns with the switching ripple frequency of the DC/DC converter. Note the switching frequency reported from WEBENCH® and design the EMI filter and capacitor combination to have the notch frequency centered as needed. Figure 7-5 and Figure 7-6 illustrate the two approaches.

AVDD and IOVDD supply voltages should not be shared to prevent digital switching noise from coupling into the analog signal chain.

ADC3910D025 ADC3910D065 ADC3910D125 ADC3910S025 ADC3910S065 ADC3910S125 Example: LDO Linear Regulator Approach
Figure 7-5 Example: LDO Linear Regulator Approach
ADC3910D025 ADC3910D065 ADC3910D125 ADC3910S025 ADC3910S065 ADC3910S125 Example: Switcher-Only Approach
Figure 7-6 Example: Switcher-Only Approach