Hi Raghavendra or should I call you Rao,
A plea from a former lamination guy.
Please keep the realities of the manufacturing process in mind. The
impedance coupons I remember didn't have alot of copper - hence an area of
reduced pressure. To make matters worse the artwork department would place
the coupon in the panel border area. This are might not be representative
of the board area. The result, a coupon that might pass impedance testing
when the boards wouldn't or a coupon that would fail when the boards were
fine. If the lamination cycle was borderline for the design we'd get resin
voids in the coupons.
It's been a while since I got my hands dirty (in pcb fab at least) so if
I've got something wrong speak up.
Hans
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
AC-130 Systems Engineer (Hardware)
Warner Robins Air Logistics Center (WR-ALC)
226 Cochran Street
Robins AFB, GA 31098-1622
Tele: (478) 926 - 5847 [DSN Prefix: 468]
Fax: (478) 926 - 4911
mailto:[log in to unmask]
-----Original Message-----
From: Brian Butler [mailto:[log in to unmask]]
Sent: Tuesday, March 18, 2003 9:40 PM
To: [log in to unmask]
Subject: Re: [TN] Test coupon for Impedance Control Board.
Raghavendra,
The IPC publishes a standard IPC 2141 document which discusses HIgh
Frequency design issues including controlled impedance coupon design. The
document is available from IPC at www.ipc.org. (This document is currently
under revision).
Sincerely,
Brian Butler
Introbotics Corporation
At 05:43 PM 3/18/03 +0530, you wrote:
>Hello everybody,
>
>I am in the process of design of Test Coupon for the fabrication of
>Impedance Control Board. Kindly help me by sending inputs regarding the
>points to be considered for design of test coupon for Impedance Control
>Board.
>
>Is any one is having detailed drawing or Gerber of test coupon?
>
>Raghavendra Rao
>[log in to unmask]
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