SBOS996C May   2020  – May 2021 LMH9235

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
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Matching to a 100 Ω AFE
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Shifting the Operating Band
        1. 8.2.2.1 Design Requirements and Procedure
        2. 8.2.2.2 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1 Layout Guidelines

When designing with an RF amplifier operating in the frequency range 3.3 GHz to 3.8 GHz with relatively high gain, certain board layout precautions must be taken to ensure stability and optimum performance. TI recommends that the LMH9235 board be multi-layered to improve thermal performance, grounding, and power-supply decoupling. Figure 10-1 shows a good layout example. In this figure, only the top signal layer is shown.

  • Excellent electrical connection from the thermal pad to the board ground is essential. Use the recommended footprint, solder the pad to the board, and do not include a solder mask under the pad.
  • Connect the pad ground to the device terminal ground on the top board layer.
  • Ensure that ground planes on the top and any internal layers are well stitched with vias.
  • Design the input and output RF traces for appropriate impedance. TI recommends grounded coplanar waveguide (GCPW) type transmission lines for the RF traces. Use a PCB trace width calculator tool to design the transmission lines.
  • Avoid routing clocks and digital control lines near RF signal lines.
  • Do not route RF or DC signal lines over noisy power planes.
  • Place supply decoupling caps close to the device.
  • The differential output traces must be symmetrical in order to achieve the best differential balance and linearity performance.

See the LMH9235 Evaluation Module user's guide for more details on board layout and design.