FROM: BRUCE HOUGHTON 27/552/844/TOR Phone (416) 448-5701 Tie 778-5701 Subject: Gold Thickness Requirements for Tabs Jedic spec for Gold Tab SIMMS is minimum of 30 micro inches of hard plated gold over minimum (I think - I am not at work) 70 micro inches in nickel. There are companies using electoless nickel/immersion gold (5 micro inches) on SIMMS. THe don't meet spec. Life expectancy / reliability is unknown. WIth the proce of SIMMS, I personally want parts that meet spec. These SIMMS plug into Gold plated connectors. There is also a tin/lead spec for SIMMS that are plugged into connectors with tin/lead plating. That spec calls for 200 microinches of tin/lead over 70 microinches of nickel, as a physical and intermetalic growth barrier. Again, there are companies that are applying solder over bare copper. Gold tab cards and tin/lead SIMMs should not be mixed in their connectors. If Gold tab SIMMS are plugged into tin/lead connectors, a high resistance intermetalic layer will grow between the gold and tin/lead and cause noise problems and failures. The same is true with tin/lead tab SIMMS in Gold connectors. Again, some companies and computer stores are mixing parts. Bruce Houghton Staff Engineer, Celestica, Inc. Internet: [log in to unmask] *** Forwarding note from SMTP2 --IINUS1 08/31/95 04:29 ***