• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 47 subscribers
  • Views 1216 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.

PCB for high speed amplifier

witat rangtain
Prodigy 60 points

Other Parts Discussed in Thread: DEM-OPA-SO-1A

Hello TI engineers

     I saw PCB for high speed amplifier DEM-OPA-SO-1A like a picture and I have 2 questions about this design.

1. Why top side has no ground plane?

2. Why ground plane at bottom side blank area IC ?

Best regards

Witat

  • 0
    TI__Genius 13935 points

    Hello Witat,

    I can't answer for the missing ground plane on the top layer, but the cut out from under the amplifier is to reduce parasitic capacitance on the I/O pins.  The inverting input and the output pins are both sensitive to parasitic capacitance.  This is explained on page 5 of the datasheet. 

    This looks like an older design.  We don't use many through hole SMA connectors anymore.  Edge mounted connectors provide a better impedance match. 

    Loren