Actions
Forum Thread Details
  • Replies 2 replies
  • Subscribers 179 subscribers
  • Views 943 views
  • Users 0 members are here
Related

Tapering Transmisson Line in EAGLE CAD

Former Member

hello every one,

I am designing an evaluation board for an IC using EAGLE CAD, whose

information can be viewed on this link

http://www.hittite.com/content/documents/data_sheet/hmc144lc4.pdf. the end

of this document shows the pcb for this IC.

 

I have designed something shown in the attached image(zoomed only to show

ic connections).

Since all the lines are 50 ohm, their width is about 0.45 mm. a close look

shows that the IC pads are smaller then the microstrip line i.e 0.25 mm.

 

Will this huge width affect the neighboring pad which are connected to

ground plan.

From the data sheet they suggests the line tip attaching the IC PAD shall

be tappered.

 

So how can i apply tapering in EAGLE CAD, and what is the theory behing it,

how to select tapering width and how much length to tapered..

--

Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

 

Attachments:
image
Parents

  • I don't know of any "simple" tapering method.

    Run short 0.25mm stub traces away from the IC pads and then connect

    your normal width 0.45 trace to it. This will also minimize any solder

    bridges between pads.  You may be able to just change the width of the

    final trace segment to the pad, since you already have connected the

    wider trace.

    ~Marvin

     

     

    On 7/11/2012 6:40 AM, Usman Ali wrote:

    hello every one,

    I am designing an evaluation board for an IC using EAGLE CAD, whose

    information can be viewed on this link

    http://www.hittite.com/content/documents/data_sheet/hmc144lc4.pdf. the end

    of this document shows the pcb for this IC.

     

    I have designed something shown in the attached image(zoomed only to show

    ic connections).

    Since all the lines are 50 ohm, their width is about 0.45 mm. a close look

    shows that the IC pads are smaller then the microstrip line i.e 0.25 mm.

     

    Will this huge width affect the neighboring pad which are connected to

    ground plan.

    From the data sheet they suggests the line tip attaching the IC PAD shall

    be tappered.

     

    So how can i apply tapering in EAGLE CAD, and what is the theory behing it,

    how to select tapering width and how much length to tapered..

     

     

     

Reply

  • I don't know of any "simple" tapering method.

    Run short 0.25mm stub traces away from the IC pads and then connect

    your normal width 0.45 trace to it. This will also minimize any solder

    bridges between pads.  You may be able to just change the width of the

    final trace segment to the pad, since you already have connected the

    wider trace.

    ~Marvin

     

     

    On 7/11/2012 6:40 AM, Usman Ali wrote:

    hello every one,

    I am designing an evaluation board for an IC using EAGLE CAD, whose

    information can be viewed on this link

    http://www.hittite.com/content/documents/data_sheet/hmc144lc4.pdf. the end

    of this document shows the pcb for this IC.

     

    I have designed something shown in the attached image(zoomed only to show

    ic connections).

    Since all the lines are 50 ohm, their width is about 0.45 mm. a close look

    shows that the IC pads are smaller then the microstrip line i.e 0.25 mm.

     

    Will this huge width affect the neighboring pad which are connected to

    ground plan.

    From the data sheet they suggests the line tip attaching the IC PAD shall

    be tappered.

     

    So how can i apply tapering in EAGLE CAD, and what is the theory behing it,

    how to select tapering width and how much length to tapered..

     

     

     

Children
No Data