SBOSAA3A July   2024  – November 2024 TRF1108

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
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 AC-Coupled Configuration
      2. 6.3.2 DC-Coupled Configuration
    4. 6.4 Device Functional Modes
      1. 6.4.1 Power-Down Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Thermal Considerations
    2. 7.2 Typical Application
      1. 7.2.1 RF DAC Buffer Amplifier
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
    3. 7.3 Power Supply Recommendations
      1. 7.3.1 Single-Supply Operation
      2. 7.3.2 Dual-Supply Operation
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.2.1.2 Detailed Design Procedure

Select an RF DAC such as the DAC39RF10 for this application because this DAC supports sampling at 10.24GSPS and the required RF signal frequency range of 4GHz. The DAC39RF10 outputs a signal level of –0.2dBm at 1GHz when operating at –1dBFS in the DES2X, 20.5mA current mode. The TRF1108 has a gain of 15.4dB and OP1dB of 12dBm at 1GHz; therefore, add approximately 9dB pad at the output of the DAC to get 6.2dBm output power. The pad loss can be reduced to 3dB if the DAC is run at –7dBFS in the 20.5mA current mode, or –1dBFS in the 10mA current mode. A 5GHz low-pass filter can optionally be added to reject the DAC images in the second Nyquist zone. From the TRF1108 specifications, the device meets the design requirement of output return loss. Table 7-2 shows the component values for attenuator and low-pass filter for the design.

Table 7-2 Component Values for Attenuator and Low-Pass Filter for the DAC39RF10 Interface
SECTION DESIGNATOR TYPE VALUE
Pad R1 Resistor 22Ω
Pad R2 Resistor 94Ω
Pad R3 Resistor 22Ω
Low-pass filter C1 Capacitor 0.5pF
Low-pass filter C2 Capacitor 0.8pF
Low-pass filter C3 Capacitor 0.5pF
Low-pass filter L1 Inductor 2nH
Low-pass filter L2 Inductor 2nH