[SI-LIST] AW: FR4 Permittivity
- From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
- To: "cyril.chastang@xxxxxxxxxxxxxxx" <cyril.chastang@xxxxxxxxxxxxxxx>, "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Thu, 21 Feb 2013 13:16:01 +0000
This isn't good data.
First of all, they only tested only once (you can tell that there is no
variation in their Test results).
Second, they don't specify the test Method they used, and there are official
test methods giving totally wrong results (the old 1MHz plate capacitor method
@ 1MHz used to be quite inaccurate).
Third, the Data is measured at 1MHz, thus these values are useless for speeds
exceeding 100MHz
I recommend to go by the Datasheet (Isola is usually very good at dk/df
testing), or test it on your own, but 2.173 is physically impossible for glass
reinforced resin as the glass altready has a much higher dk.
BR
Gert
----------------------------------------
Absender ist HARTING Electronics GmbH, Marienwerderstraße 3, D-32339 Espelkamp;
Registergericht: Amtsgericht Bad Oeynhausen; Register-Nr.: HRB 8808;
Vertretungsberechtige Geschäftsführer: Dipl.-Kfm. Edgar-Peter Düning,
Dipl.-Ing. Torsten Ratzmann
-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im
Auftrag von CHASTANG Cyril
Gesendet: Donnerstag, 21. Februar 2013 13:49
An: si-list@xxxxxxxxxxxxx
Betreff: [SI-LIST] FR4 Permittivity
Apparently, the screenshot is invisible in my previous email. I have the
following data:
Grade: PLC-FR-370HR H/H(RTF)
Thickness: 0.004 in
Customer: SanminaSIN
Test Property | Unit | Condition
| Sampling | Test Results
| Specs
Dissipation factor | - | IPC-4101*A C-40/23/50 @1MHz
| 1/month | Ave: 0.007 [0.007 - 0.007] | 0.035
Diectric constant | - | IPC-4101*A C-40/23/50 @1MHz
| 1/month | Ave: 2.173 [2.173 - 2.173] | 0-5.4
Thank you.
Best regards,
Cyril
________________________________________________________
Hi,
I have recently received a PCB (dielectric= Isola PLC-FR-370HR) and its
certificate of compliance (extract below). The value of the material
permittivity given below is quite surprising (2.173) to be FR4. Is it the
effective permittivity for a microstrip? Is there a mistake in the certificate?
Have you ever seen a FR4 permittivity like that ?
Thank you for your help.
Cyril
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