Trust me when I say that the technology would have worked just as well in the metric system ;-) and the calculations and conversions would have been much easier. (It was, in fact, a Soviet rocket designed using the metric system that put the first man made device on the moon.) Who knows NASA might have even got there sooner if everything was designed in metric and Shepard might have been able to complete an 18 crater round instead of just hitting a couple of golf balls. ;-) Joe In a message dated 10/17/2009 6:24:21 A.M. Pacific Daylight Time, [log in to unmask] writes: The USA played golf on the Moon 40 years ago using that old arcane and archaic system...Metric system countries that have played golf on the Moon? Oh yeah...none :) -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Joe Fjelstad Sent: Friday, October 16, 2009 4:41 PM To: [log in to unmask] Subject: Re: [TN] No Soldermask between Fine pitch QFN and QFP Hello Amol Since all electronic components are now designed, registered and fabricated using the metric system, would not it be easier to ask for a 0.5mm pitch device with lands of 0.25mm by 0.7mm? This is one of the windmills I continue to joust and I am constantly curious why we in the US continue to be so wedded to such an arcane and archaic measurement system as that which we inherited/adopted from our English forefathers. Consider the following from the web: The metric system originated in France in the 1790's, a few years after Jefferson's proposals. (note: Jefferson proposed to metric English system for the US in the 1780 time frame where there were to 10 inches to the foot, 10 feet to a decade, 100 feet to a rood, 1000 feet to the furlong and 10,000 feet to the mile) During the mid-nineteenth century, as expanding trade demanded a consistent set of measurements, use of the metric system spread through continental Europe. As they imported goods from Europe or exported goods to Europe, Americans became increasingly aware of the metric system. In 1866, Congress legalized its use in an act reading: It shall be lawful throughout the United States of America to employ the weights and measures of the metric system; and no contract or dealing, or pleading in any court, shall be deemed invalid or liable to objection because the weights or measures expressed or referred to therein are weights or measures of the metric system. As a result, the U. S. has been "metric" since 1866, but only in the sense that Americans have been free since that time to use the metric system as much as they like. Although there has always been popular resistance to changing the traditional measures, the metric system has actually enjoyed strong support from American business leaders and scientists since the late nineteenth century. In 1875, the U.S. was one of the original signers of the Treaty of the Meter." and I might add that we continue to move towards complete metrication of our national measurement systems "inch by inch"... ;-) Joe In a message dated 10/16/2009 10:55:25 A.M. Pacific Daylight Time, [log in to unmask] writes: I am looking at a 19.7 mil pitch QFN device with a center pad and peripheral pads at 9.8x27.5 mils, and a 176 pin fine pitch QFP with 11.8x63 mil pads with HASL finish and without any soldermask in between the peripheral pads!...has anybody seen this type of a board design before? Any stencil design suggestions? I have a couple of pictures I have requested Steve to post for me regarding the parts ( I am awaiting Steve's reply) Thanks, Amol WARNING: Export Control This document may contain technical data within the definition of the International Traffic in Arms Regulations (ITAR), and subject to the Export Control Laws of the U.S. Government. Transfer of such data by any means to a foreign person, whether in the United States or abroad, without proper export authorization or other approval from the U.S. Department of State is prohibited. CONFIDENTIALITY NOTICE: This e-mail, and any attachments, is for the sole use of the intended recipient(s) and may contain information that is confidential and protected from disclosure under the law. Any unauthorized review, use, disclosure, or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail, and delete/destroy all copies of the original message and attachments. Thank you. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------