SBASAU8 December   2024 ADC3649

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 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 (ADC3648 - 250 MSPS)
    8. 6.8  Electrical Characteristics - AC Specifications (ADC3649 - 500 MSPS)
    9. 6.9  Timing Requirements
    10. 6.10 Typical Characteristics, ADC3648
    11. 6.11 Typical Characteristics, ADC3649
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Analog Inputs
        1. 8.3.1.1 Nyquist Zone Selection
        2. 8.3.1.2 Analog Front End Design
      2. 8.3.2 Sampling Clock
      3. 8.3.3 Multi-Chip Synchronization
        1. 8.3.3.1 SYSREF Monitor
      4. 8.3.4 Time-Stamp
      5. 8.3.5 Overrange
      6. 8.3.6 External Voltage Reference
      7. 8.3.7 Digital Gain
      8. 8.3.8 Decimation Filter
        1. 8.3.8.1 Uncommon Decimation Ratios
        2. 8.3.8.2 Decimation Filter Response
        3. 8.3.8.3 Decimation Filter Configuration
        4. 8.3.8.4 Numerically Controlled Oscillator (NCO)
      9. 8.3.9 Digital Interface
        1. 8.3.9.1 Parallel LVDS
        2. 8.3.9.2 Serial LVDS (SLVDS) with Decimation
          1. 8.3.9.2.1 SLVDS - Status Bit Insertion
        3. 8.3.9.3 Output Data Format
        4. 8.3.9.4 32-bit Output Resolution
        5. 8.3.9.5 Output Scrambler
        6. 8.3.9.6 Output MUX
        7. 8.3.9.7 Test Pattern
    4. 8.4 Device Functional Modes
      1. 8.4.1 Low Latency Mode
      2. 8.4.2 Digital Channel Averaging
      3. 8.4.3 Power Down Mode
    5. 8.5 Programming
      1. 8.5.1 GPIO Programming
      2. 8.5.2 Register Write
      3. 8.5.3 Register Read
      4. 8.5.4 Device Programming
      5. 8.5.5 Register Map
      6. 8.5.6 Detailed Register Description
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Wideband Spectrum Analyzer
      2. 9.2.2 Design Requirements
        1. 9.2.2.1 Input Signal Path
        2. 9.2.2.2 Clocking
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Sampling Clock
      4. 9.2.4 Application Performance Plots
    3. 9.3 Initialization Set Up
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Third-Party Products Disclaimer
    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
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

9.2.3.1 Sampling Clock

To maximize the SNR performance of the ADC, a low jitter (< 75fs) sampling clock is required. Figure 9-2 shows the estimated SNR performance vs input frequency vs external clock jitter. The internal ADC aperture jitter also has some dependence to the clock amplitude (gets more sensitive with higher input frequency) as shown in Figure 9-3.

When using averaging and/or decimation, the SNR for a single ADC core must be estimated first before adding the SNR improvement from internal averaging and/or decimation.

ADC3649 SNR vs TJitter vs FIN

Figure 9-2 SNR vs TJitter vs FIN
ADC3649 SNR vs Clock Amplitude
FS = 500MSPS FIN = 100MHz AIN = -1dBFS
Figure 9-3 SNR vs Clock Amplitude