SBASAL2 November   2025 ADC32RF72

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
    8. 5.8 Timing Requirements
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Inputs
        1. 7.3.1.1 Input Bandwidth
        2. 7.3.1.2 Background Calibration
      2. 7.3.2 ADC Channel Selection and Power Down Modes
      3. 7.3.3 Sampling Clock Input
      4. 7.3.4 SYSREF
        1. 7.3.4.1 SYSREF Monitor
      5. 7.3.5 Digital Signal Processor (DSP) Features
        1. 7.3.5.1 DSP Input Mux
        2. 7.3.5.2 Fractional Delay
        3. 7.3.5.3 Programmable FIR Filter for Equalization
        4. 7.3.5.4 DSP Output Mux
        5. 7.3.5.5 Digital Down Converter (DDC)
          1. 7.3.5.5.1 Decimation Filter Input
          2. 7.3.5.5.2 Decimation Modes
          3. 7.3.5.5.3 Decimation Filter Response
          4. 7.3.5.5.4 Numerically Controlled Oscillator (NCO)
            1. 7.3.5.5.4.1 NCO Update
            2. 7.3.5.5.4.2 NCO RESET
      6. 7.3.6 Digital Output Interface
        1. 7.3.6.1 JESD204B/C Interface
          1. 7.3.6.1.1 JESD204B Initial Lane Alignment (ILA)
          2. 7.3.6.1.2 SYNC Signal
          3. 7.3.6.1.3 JESD204B/C Frame Assembly
          4. 7.3.6.1.4 JESD204B/C Frame Assembly in Bypass Mode
          5. 7.3.6.1.5 JESD204B/C Frame Assembly With Real Decimation
          6. 7.3.6.1.6 JESD204B,C Frame Assembly With Complex Decimation
        2. 7.3.6.2 JESD Output Reference Clock
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Operating Mode Comparison
    5. 7.5 Programming
      1. 7.5.1 GPIO Control
      2. 7.5.2 SPI Register Write
      3. 7.5.3 SPI Register Read
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application: Spectrum Analyzer
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Input Signal Path: Wideband Receiver
        2. 8.2.1.2 Clocking
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Sampling Clock Requirements
      3. 8.2.3 Application Performance Plots
    3. 8.3 Typical Application: Time Domain Digitizer
      1. 8.3.1 Design Requirements
        1. 8.3.1.1 Input Signal Path: Time Domain Digitizer
      2. 8.3.2 Application Performance Plots
    4. 8.4 Initialization Set Up
    5. 8.5 Power Supply Recommendations
    6. 8.6 Layout
      1. 8.6.1 Layout Guidelines
      2. 8.6.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
      2. 9.1.2 Third-Party Products Disclaimer
    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
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.3.1.1 Input Signal Path: Time Domain Digitizer

Most time-domain digitizers are required to be DC-coupled to monitor DC or low-frequency signals. This requirement forces the design to use DC-coupled, fully differential amplifiers to convert from single-ended signaling at the front panel to differential signaling at the ADC. This design uses a differential amplifier. The LMH5401 amplifier has an 8GHz, gain-bandwidth product that is sufficient to support a 1GHz bandwidth digitizer. The LMH5401 has a gain of 8dB and a noise figure of 11dB.

An antialiasing, low-pass filter is positioned at the input of the ADC to limit the bandwidth of the input signal into the ADC. This amplifier also band-limits the front-end noise to prevent aliased noise from degrading the signal-to-noise ratio of the overall system. Design this filter for the maximum input signal bandwidth specified by the oscilloscope. The input bandwidth can then be reconfigured through the use of digital filters in the FPGA or ASIC to limit the oscilloscope input bandwidth to a bandwidth less than the maximum.

Table 8-2 lists a number of recommended amplifiers frequency ranges.

Table 8-2 Recommended single ended to differential amplifiers
PART NUMBERBANDWIDTHPOWER CONSUMPTION
THS45091.9GHz125mW
LMH54018GHz185mW
TRF13057GHz495mW