Re: [SI-LIST] : HF SCSI connectors

Don Abernathey ([email protected])
Tue, 9 Dec 1997 09:43:04 -0800

On Dec 9, 4:34am, Charles Hill wrote:
> I have noticed mini DB-50 connector SCSI cables for sale and my Adaptec
2940UW board has a 68 pin connector on 0.050 spacing. These are much smaller
> From: [email protected][SMTP:[email protected]]
> with it is that when it comes to connector design, connectors such as SCSI
> an DB-9's aren't designed for Gigabit/sec and higher data rates but people
> are using them anyway. This makes is a problem when designing a cable
> since there is usually a connector at either end. Yes some vendors
> incorperate little closely spaced dimples to provide better contact between
> the header and connector but from some of the testing I've been doing I'm
> finding that the weak link EMI-wise is header-connector interface as
> opposed to the rest of the cable assembly. So the question is has anyone
> found a vendor out there that's doing anything innovative in the way of
> high frequency SCSI or DB-9 connectors.

I have used the AMPlimite .050"-series connectors successfully in
designs in days past. The versions that mount to a PCB (soldertail or
pressfit) have the drawback that they only ground on each end of the
connector. I.e. you can ground the recepticle housing to the PCB, but
only at the ends. The length between grounding points limits the
usefullness above a certain frequency at which you must augment the
grounding mechanically. The connector, backshell, recepticle assembly,
when used with braid over foil cable is very good. I've spent a fair
amount of time at the EMI test site with this stuff and it was always
the least of my worries.

The replacement for DB9's in Fibre Channel (GigaBit Etherhose)
applications is the AMP HSSDC or the Berg MetaGig connectors. Call
AMP's AmpFax line 1-800-522-6752 and get info on PN# 636180-1. They
also have EMI-test data (pdf's) which may or may not be on their web
page now.

Thank you |
Don Abernathey |
(503)690-6234 |
[email protected] |