SBOU266B september   2021  – august 2023 TRF1208

 

  1.   1
  2.    TRF1208 Evaluation Module
  3.   Trademarks
  4. 1Description
    1. 1.1 Features
    2. 1.2 General Usage Information
  5. 2EVM Overview
    1. 2.1 Schematic
    2. 2.2 PCB Layers
    3. 2.3 TRF1208 EVM Bill of Material
    4. 2.4 Stack-Up and Material
  6. 3Test Setup Diagrams
    1. 3.1 S-Parameter Test Setup
    2. 3.2 Noise Figure Test Setup
    3. 3.3 Two-Tone OIP3 Test Setup
  7. 4Related Documentation
  8. 5Revision History

1.2 General Usage Information

This section provides general usage information for the TRF1208 EVM. See Figure 1-1 for a general single tone setup diagram as a reference point for the following instructions (some components, such as supply bypass capacitors, are omitted for clarity):

  1. Recommended power up sequence:
    1. Before connecting the power-supply cables to the EVM, set the DC output power supply to +3.3 V.
    2. Set the current limit of the DC output power supply at 250 mA.
    3. Making sure the supply is turned off, connect the power supply cables to the J1 connector of the EVM.
    4. Now turn on the DC power supply of VCC = +3.3 V. The supply current (IQ) drawn from the power supply is approximately 135 mA.
    5. If the supply current is low, then verify that the device is not disabled by the PD pin.
  2. Power-down option:
    1. Connect +1.8 V (logic-1) on PD pin to power-down the chip. Ground the PD pin to enable the chip.
  3. Single tone measurement setup recommendation:
    1. Connect an RF signal generator to input SMA connector, J4.
      When measuring single tone distortion, use an RF band pass filter as shown in Figure 1-1.
    2. The RF signal generator used must support up to 12-GHz signal frequency for testing out the TRF1208 EVM.
    3. The TRF1208 device input is 50-Ω in the pass-band.
      To minimize signal reflections due to impedance mismatch, TI recommends using an attenuator pad of approximately 3-dB to 6-dB between the source and J4 SMA input.
    4. The EVM outputs are fully differential (or 180° out-of-phase) at J5 and J6 SMA connectors.
      The TRF1208 device has low output impedance at dc and low frequencies.
    5. When connecting to a spectrum analyzer, the differential signal out of the EVM must be converted to a single-ended signal using an external passive balun as shown in Figure 1-1.
      Usage of an attenuator pad of approximately 3-dB to 6-dB is recommended at the three terminals of the passive balun to minimize reflections.
    6. Lastly, TI recommends to properly characterize and account for the insertion loss of RF coaxial (coax) cables, attenuator pads, and passive baluns to measure accurate gain and power levels for the device.
  4. Matching considerations:
    1. TRF1208 is a wide-band amplifier and expects 50-Ω input matching over the operating bandwidth up to about 12 GHz. A signal generator or Noise Source that drives this EVM has 50-Ω impedance over a wide band width. But, if this EVM is driven by a narrow-band driver or a source that has non 50-Ω matching, then there can be instability issues with the amplifier. To avoid such issues, additional matching can be required at the input. See the TRF1208 Single Channel, 10 MHz to 8 GHz 1-dB BW, Single Ended to Differential Amplifier data sheet for more information.
    2. As mentioned earlier, the TRF1208 device has low output impedance, and zero-ohm series resistors are used in the EVM. When the EVM outputs are connected to a balun, TI recommends to use attenuator pads to minimize reflections.