SBAS840C July   2020  – December 2022 ADC3541 , ADC3542 , ADC3543

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 - Power Consumption
    6. 6.6  Electrical Characteristics - DC Specifications
    7. 6.7  Electrical Characteristics - AC Specifications ADC3541
    8. 6.8  Electrical Characteristics - AC Specifications ADC3542
    9. 6.9  Electrical Characteristics - AC Specifications ADC3543
    10. 6.10 Timing Requirements
    11. 6.11 Typical Characteristics: ADC3541
    12. 6.12 Typical Characteristics: ADC3542
    13. 6.13 Typical Characteristics: ADC3543
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Analog Input
        1. 8.3.1.1 Analog Input Bandwidth
        2. 8.3.1.2 Analog Front End Design
          1. 8.3.1.2.1 Sampling Glitch Filter Design
          2. 8.3.1.2.2 Single Ended Input
          3. 8.3.1.2.3 Analog Input Termination and DC Bias
            1. 8.3.1.2.3.1 AC-Coupling
            2. 8.3.1.2.3.2 DC-Coupling
        3. 8.3.1.3 Auto-Zero Feature
      2. 8.3.2 Clock Input
        1. 8.3.2.1 Single Ended vs Differential Clock Input
        2. 8.3.2.2 Signal Acquisition Time Adjust
      3. 8.3.3 Voltage Reference
        1. 8.3.3.1 Internal voltage reference
        2. 8.3.3.2 External voltage reference (VREF)
        3. 8.3.3.3 External voltage reference with internal buffer (REFBUF)
      4. 8.3.4 Digital Down Converter
        1. 8.3.4.1 Digital Filter Operation
        2. 8.3.4.2 FS/4 Mixing with Real Output
        3. 8.3.4.3 Numerically Controlled Oscillator (NCO) and Digital Mixer
        4. 8.3.4.4 Decimation Filter
        5. 8.3.4.5 SYNC
        6. 8.3.4.6 Output Formatting with Decimation
          1. 8.3.4.6.1 Parallel CMOS
          2. 8.3.4.6.2 Serialized CMOS Interface
      5. 8.3.5 Digital Interface
        1. 8.3.5.1 Parallel CMOS Output
        2. 8.3.5.2 Serialized CMOS output
          1. 8.3.5.2.1 SDR Output Clocking
        3. 8.3.5.3 Output Data Format
        4. 8.3.5.4 Output Formatter
        5. 8.3.5.5 Output Bit Mapper
        6. 8.3.5.6 Output Interface/Mode Configuration
          1. 8.3.5.6.1 Configuration Example
      6. 8.3.6 Test Pattern
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal operation
      2. 8.4.2 Power Down Options
    5. 8.5 Programming
      1. 8.5.1 Configuration using PINs only
      2. 8.5.2 Configuration Using the SPI Interface
        1. 8.5.2.1 Register Write
        2. 8.5.2.2 Register Read
    6. 8.6 Register Map
      1. 8.6.1 Detailed Register Description
  9. 9 Application Information Disclaimer
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Input Signal Path
        2. 9.2.2.2 Sampling Clock
        3. 9.2.2.3 Voltage Reference
      3. 9.2.3 Application Curves
    3. 9.3 Initialization Set Up
      1. 9.3.1 Register Initialization During Operation
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.4.1 Digital Filter Operation

The complex decimation operation is illustrated with an example in Figure 8-21. First the input signal (and the negative image) are frequency shifted by the NCO frequency as shown on the left. Next a digital filter is applied (centered around 0 Hz) and the output data rate is decimated - in this example the output data rate FS,OUT = FS/8 with a Nyquist zone of FS/16. During the complex mixing the spectrum (signal and noise) is split into real and complex parts and thus the amplitude is reduced by 6-dB. In order to compensate this loss, there is a 6-dB digital gain option in the decimation filter block that can be enabled via SPI write.

GUID-5CDDB3A3-BFDC-4322-BB11-DE53B0DC23AD-low.gif Figure 8-21 Complex decimation illustration

The real decimation operation is illustrated with an example in Figure 8-22. There is no frequency shift happening and only the real portion of the complex digital filter is exercised. The output data rate is decimated - a decimation of 8 would result in an output data rate FS,OUT = FS/8 with a Nyquist zone of FS/16.

During the real mixing the spectrum (signal and noise) amplitude is reduced by 3-dB. In order to compensate this loss, there is a 3-dB digital gain option in the decimation filter block that can be enabled via SPI write.

GUID-6CC12DEE-97D3-41C6-9398-B2FB424191D9-low.gif Figure 8-22 Real decimation illustration