SBAS886A October   2020  – May 2022 ADC3641 , ADC3642 , ADC3643

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 ADC3641
    8. 6.8  Electrical Characteristics - AC Specifications ADC3642
    9. 6.9  Electrical Characteristics - AC Specifications ADC3643
    10. 6.10 Timing Requirements
    11. 6.11 Typical Characteristics - ADC3641
    12. 6.12 Typical Characteristics - ADC3642
    13. 6.13 Typical Characteristics - ADC3643
  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 DDC MUX
        2. 8.3.4.2 Digital Filter Operation
          1. 8.3.4.2.1 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
      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 Maps
      1. 8.6.1 Detailed Register Description
  9. 9 Application and Implementation
    1. 9.1 Typical Application
      1. 9.1.1 Design Requirements
      2. 9.1.2 Detailed Design Procedure
        1. 9.1.2.1 Input Signal Path
        2. 9.1.2.2 Sampling Clock
        3. 9.1.2.3 Voltage Reference
      3. 9.1.3 Application Curves
    2. 9.2 Initialization Set Up
      1. 9.2.1 Register Initialization During Operation
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3.2 External voltage reference (VREF)

For highest accuracy and lowest temperature drift, the VREF input can be directly connected to an external 1.6 V reference. A 10 μF and a 0.1 μF ceramic bypass capacitor (CVREF) connected between the VREF and REFGND pins and placed as close to the pins as possible is recommended. The load current from the external reference is about 1 mA.
Note: The internal reference is also used for other functions inside the device; therefore, the reference amplifier should only be powered down in power down state but not during normal operation.

Figure 8-18 External 1.6V reference