Hello Stacy,
JEDEC Standard MO-161 issue E (9/2000) has the answers you are looking for.
This standard is available for free at
http://www.jedec.org/download/default.cfm Here is a summary of the heights
for all 168-pin DIMM variations listed in the standard. These are
applicable to both first and second generation types, all keying styles and
both 4.0mm and 9.0mm thick modules.
Variation Height, mm +/-0.13 Height, in. +/-0.005
--------- ------------------ --------------------
AA, AB 25.40 1.000
BA, BB 31.75 1.250
CA, CB 38.10 1.500
CC, CD 43.18 1.700
The standards committee either liked asymmetry or wanted to drive us
compulsive types crazy. Kudos to them. Since the widths are all the same,
you should be able to standardize your subpanels to four variations, at
most. The overall PCB thickness is 1.27+/-0.1mm (0.050"+/-0.004") for all
of them. Hope this helps.
Regards,
Seth Goodman
Goodman Associates, LLC
tel 608.833.9933
fax 608.833.9966
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of My Nguyen
> Sent: Wednesday, January 02, 2002 4:59 PM
> To: [log in to unmask]
> Subject: Re: [TN] Panel Layout Standardization - PCB height increment
>
>
> Hinner,
>
> Typically, a regular DIMM/SIMM module is about 0.020
> to 0.0500 THICK and 1.000" to 1.500" HEIGHT.
>
> I was asking to find out if there is any common
> standard for the Height (not thickness) increment.
> i.e 0.125. Because from my personal experience,
> Layout Engineers from different company or different
> school (even finally they work for the same company)
> may layout a similar PCB at two different height, i.e
> A regular 168 PIN DIMM 5.25 x 1.200 for one and 5.25 x
> 1.250 for another.
>
> If it happens, manufacturing will be caught by
> surprise. They would not have tool and fixture for
> the suprised board. It would take us up to 4 weeks to
> order a pricise tool for depanelization fixture for
> our machines.
>
> A standard increment in PCB height will help
> manufacturing to be fully prepare for current and
> future products. I.e. tool and fixture for 1.000,
> 1.125, 1.250, 1.375, 1.500, etc set.
>
> Please let us know if you have any expert advise or
> opinion.
>
> Thanks,
>
> Stacy
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