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| -rw-r--r-- | mechanical-specifications.typ | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/mechanical-specifications.typ b/mechanical-specifications.typ index 767f795..ebb8864 100644 --- a/mechanical-specifications.typ +++ b/mechanical-specifications.typ @@ -399,6 +399,44 @@ All PCBs shall pass the following tests before assembly: #include "tables/pcb-electrical-testing-requirements.typ" +==== Component packaging and repairability +<component-packaging-and-repairability> + +SAME mandates through hole components at the time of +circuit design. All components in the Bill of Material +(BOM) must then be readily available and in production: +BOMs must not include surface-mount, new old stock or +end of life components. + +We acknowledge that some components might become +unavailable later on. In that case, builders should try +to find a suitable through-hole replacement. If none is +available, we authorize the use of surface mount +components, provided that they are soldered on a +daughter board, to maintain SAME repairability goals. + +/ DIP first policy: All integrated circuits (ICs) + should use Dual In-Line (DIP) packages to maximize + field repairability and manual assembly using + through-hole soldering techniques, + +/ DIP sockets: When ICs are socketed, designs must use + machine, turned-pin gold-plated sockets. Stamped + or leaf-spring sockets are prohibited in Industrial + and Metrologic tiers due to long term contact + resistance drift. + +/ SMD adapter daughterboards: When an SMD component is + used as replacement of a now unavailable + through-hole IC, it should ne mounted on a + standardized adapter daughterboard: SOIC-to-DIP, + MSOP-to-DIP, etc. + +/ Clearance envelope: The combined height of the DIP + socket, daughterboard, and eventual SMD component + must not exceed the $qty(30, "mm")$ component + keep-out clearance from the PCB surface. + === Panels <panels> ==== Geometry <panels-geometry> |