[SI-LIST] : BackPlane stackup

John Lin - TAO (LinJohn@mail.dec.com)
Tue, 29 Jul 1997 10:52:34 +0800

Hi,

Can somebody tell me about if it is feasible to have the
stackup configuration, as following, for a backplane design ?

---------------------------------Ground plane
1
35 mils
----------------------------------Signal
2
35 mils
-----------------------------------Ground Plane
3
15 mils
----------------------------------- Signal
4
The total thickness is 93 mils.

Doing so is to match the impedance of microstrip( layer 4) to
Stripline (layer 2) impedance to the value of 88 ohms.

I am afraid that the manufacturing cost will increase greatly
compared to the following.

---------------------------------- Ground
Plane
27 mils
---------------------------------- Signal
33 mils
---------------------------------- Signal
27 mils
----------------------------------- Ground
Plane

The total thickness is 93 mils.

Thanks in advance,

JOHNLIN
CAE Engineer of EDA Department
Digital Equipment Corp. Taiwan Branch
Email: Linjohn@mail.dec.com
TEL: 1-886-3-3900000 ext. 2565