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Adding additional gain and attenuation adjustment to the transmit path option in TSW30H84

Meenakshi Rawat
Intellectual 570 points
Other Parts Discussed in Thread: TRF3705

Hello,

I want to add additional gain and attenuation adjustment to the transmit path and trying to follow following options suggested in user guide:

For TX Path #1
• Remove C258 and R165
• Install 0Ω to R161, R163, and R293
• Install 0Ω or ferrite bead to FB23
For TX Path #2
• Remove C268 and R166
• Install 0Ω to R162, R164, and R294
• Install 0Ω or ferrite bead to FB21

I could not find C258 and C268 in the board anywhere. Where are these components on board? Is it possible that components are misprint, I am able to see (C158 and C168 at almost identical position in two channels, but I could not be not sure!! Any help is appreciated!

Moreover, Once these options are added, will I get gain performance for whole range of 300 MHz-4 GHz?

Thanks and Regards,

Meenakshi

  • 0
    TI__Guru* 78594 points

    Meenakshi,

    If you follow the schematic of the TSW30H84 board, you will see that C258 and C268 are the series cap directly at the output of the TRF3705 modulator. You can then find that C256/C268 shares the same pad as R163/R164 so you can solder/desolder the components to change the signal path.

    The amp used is MGA-30689. You may refer to the datasheet on the web to see the component values needed to cover the range. It is rated for 40MHz to 3000MHz.

    http://www.avagotech.com/docs/AV02-1876EN

    -Kang

  • 0 in reply to Kang Hsia
    Intellectual 570 points

    Hi Kang,

    Many thanks.

     

    Regards,

    Meenakshi