• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 22 subscribers
  • Views 374 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMX2615-SP: optimizing matching circuit to increase output power ( single frequency application)

Michel Gaudreault
Prodigy 10 points
Part Number: LMX2615-SP
Other Parts Discussed in Thread: LMX2615EVM-CVAL

Hello,

The LMX2615-SP wideband Synthesizer operates on a very wide band ( from 40 MHz to 15 GHz).

In my application, I'am operating at one single fixed frequency ( around 5 GHz).

On eval board LMX2615EVM-CVAL, at  5.0 GHz, with default matching circuits (red box), on channel A and B,  the measured output power is around +3.5- to+4.0 dBm.

I would like to optimize the matching circuit  to increase the output power for my fixed operating frequency.application.

Do you have an electrical model for the impedance seen at pins 36 and 37 (red arrow) ?

With such information, with ADS, I could modify the values for L1, C5, C6 and C7 to get more power.

Thanks

  • 0
    TI__Guru** 108410 points

    Hi Michel,

    we don't have the model for impedance matching design. 

    C5, C6 and C7 are AC-short. We were using a wideband capacitor in the EVM to ensure it is a short over a wide range of frequency. You can pick a regular capacitor that appears as a short at 5GHz.

    L1 is a RF-choke. You can pick one with SRF at around 5GHz.

    To increase output power, you can use inductor to replace the 50Ω pull-up resistor. Datasheet section 8.1.4 has some recommendations.