Return-Path: Received: (qmail 22897 invoked from network); 23 Jan 2002 15:52:04 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by exhibition.plus.net with SMTP; 23 Jan 2002 15:52:04 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 26115 invoked from network); 23 Jan 2002 15:51:37 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 23 Jan 2002 15:51:37 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16TPdX-0001cI-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 23 Jan 2002 15:48:31 +0000 Received: from bob.dera.gov.uk ([192.5.29.90]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16TPdW-0001cA-00 for rsgb_lf_group@blacksheep.org; Wed, 23 Jan 2002 15:48:30 +0000 Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id PAA01172; Wed, 23 Jan 2002 15:57:36 GMT Received: (qmail 4299 invoked from network); 23 Jan 2002 16:36:17 -0000 Received: from gauntlet.mail.dstl.gov.uk (192.168.9.10) by baton.dstl.gov.uk with SMTP; 23 Jan 2002 16:36:17 -0000 Received: by gauntlet.mail.dstl.gov.uk; id QAA28269; Wed, 23 Jan 2002 16:05:11 GMT Received: from unknown(172.17.128.171) by gauntlet.mail.dstl.gov.uk via smap (3.2) id xma028211; Wed, 23 Jan 02 16:04:38 GMT Received: from FRN-MAIL-R3.dstl.gov.uk (unverified) by mailguard.dstl.gov.uk (Content Technologies SMTPRS 4.1.5) with ESMTP id for ; Wed, 23 Jan 2002 15:53:56 +0000 Received: by frn-mail-r3.dstl.gov.uk with Internet Mail Service (5.5.2650.21) id ; Wed, 23 Jan 2002 15:47:06 -0000 Message-ID: <7D653C9C42F5D411A27C00508BF8803DCB9976@pdw-mail-r1.dstl.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Subject: LF: RE: SMT Devices Date: Wed, 23 Jan 2002 15:47:03 -0000 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: >Are you aware of any possibility to buy online a PCB ready made >for the AD9854 ? It would suffice a layout that brings all the pins >to more manageable pads where to connect the rest of the circuit. >I checked the Analog Devices site, but they have (for an outrageous >price...) only an evaluation board for the 9854, complete with the chip. There was a techniques described a couple of years ago for using these chips dead bug style. Mount the chip upside down on a piece of unetched PCB. Bend the grounding pins down and solder directly to the groundplane. Then get some 0805 chip capacitors and solder one end of these, standing upright, to the groundplane as close to the power supply pins as possible. Then using thin wire - eg a single strand of multistranded wire - connect the appropriate pins direct to the caps; then the signal pins to the rest of the circuit. This can give an RF layout every bit as good as a proper double sided PCB. It looks messy, but so what, it works ! >> In my last job I did a bit of chip and bond microwave circuitry. Now that >> really IS small ! Bonding 25 micron gold wire onto 0.1mm pads on bare >> GaAsFET chips. >I hope you didn't do that with unaided hands... otherwise I will dub >you SuperMan..:-) No, sorry, we had a lab wirebonder. It always needed cleaning before use as there was inevitably some individual that had left it in a dirty state with the covers off. Andy -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.