SBOS998C June   2021  – March 2022 BUF802

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: Wide Bandwidth Mode
    6. 6.6 Electrical Characteristics: Low Quiescent Current Mode
    7. 6.7 Typical Characteristics
  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 Input and Output Over-Voltage Clamp
      2. 8.3.2 Adjustable Quiescent Current
      3. 8.3.3 ESD Structure
    4. 8.4 Device Functional Modes
      1. 8.4.1 Buffer Mode (BF Mode)
      2. 8.4.2 Composite Loop Mode (CL Mode)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Oscilloscope Front-End Amplifier Design
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Transforming a Wide-Bandwidth, 50 Ω Input Signal Chain to High-Input Impedance
        1. 9.2.2.1 Detailed Design Results
        2. 9.2.2.2 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2.1 Detailed Design Results

TIDA-01022 reference design primarily focuses on a multichannel high-speed analog front-end, which is typically used in end equipment like a digital storage oscilloscope (DSO), wireless communication test equipment (WCTE), and radars. A 50 Ω input data acquisition (DAQ) signal chain like that of TIDA-01022 can be converted into a high-input impedance DAQ system by inserting the BUF802 at the front.

TIDA-01022 orginally features the following:

  • LMH5401 is a high-performance, differential amplifier with an usable bandwidth from DC to 2 GHz. It is used as single to differential conversion amplifier in this signal chain. The device offers excellent linearity performance at a fixed 12-dB gain.
  • LMH6401 is a wideband digitally controlled variable gain, differential in and differential out, amplifier. The noise and distortion performance are optimized to drive ultra-wideband ADCs. The device offers DC to 4.5-GHz bandwidth with a gain range from –6 dB to 26 dB in 1-dB steps. The gain can be controlled using a standard serial peripheral interface (SPI).
  • The ADC12DJ5200RF device is a 12 bit, giga-sample, analog-to-digital converter (ADC) that can directly sample input frequencies from DC to above 10 GHz. ADC12DJ5200RF can be configured as a dual-channel, 5.2 GSPS ADC or single-channel, 10.4 GSPS ADC.

The BUF802 along with offering high-input impedance and low-noise for the front-end amplifier, holds capability of driving matched loads of 50 Ω, making it easy to retrofit with predesigned analog front-end signal chains. Figure 9-7 to Figure 9-9 shows the comparison of native performance of the TI design TIDA-01022 and performance achieved post addition of BUF802 at the front-end. Adding BUF802 at the input of TIDA-01022 translates the original 50 Ω input imepdance TI design to a high-input impedance DAQ signal chain. A simplified schematic of BUF802 + TIDA-01022 is shown in Figure 9-6.