VME Board Sizes; Mechanical Dimension for VME cards

VITA 48 "Ruggedized Enhanced Design Implementation" (REDI) draft standard for 3U and 6Ux160mm commercial off-the-shelf (COTS) modules.
This standard intends to create a unified mechanical standard for 3U and 6U COTS modules using air, conduction or liquid-cooling methods.
The REDI mechanical enhancements are independent of electrical standards such as VITA 46 (VPX) or VITA 41 (VXS).
The first initiative underway combines VITA 46 and VITA 48 to produce a next-generation platform called VPX-REDI.

REDI has increased the maximum allowed pitch (or spacing) between modules to 1" from the IEEE 1101 standard of 0.8".

A greater maximum PWB thickness is also allowed. Whereas IEEE 1101 practice allows for a 0.063" maximum PWB thickness, REDI accounts for up to a 0.120" thickness.

.... The air and conduction-cooling sections of the standard push the ceiling of thermal management to 200W per module.
Use of the liquid-cooling methodologies of VITA 48 is intended to allow upwards of 500W in a single module slot.....

VITA 48 REDI standard:
VITA 48.0 - Mechanical Specifications for Microcomputers Using Ruggedized Enhanced Design Implementation (REDI)
VITA 48.1 - Mechanical Specifications for Microcomputers REDI Air Cooling Applied to VITA 46
VITA 48.2 - Mechanical Specifications for Microcomputers REDI Conduction Cooling Applied to VITA 46
VITA 48.3 - Mechanical Specifications for Microcomputers REDI Liquid Cooling Applied to VITA 46

IEEE 1101.1 Base Document for Mechanics ~ Defines 3U/6U/9U (high) x 100/160/220/280/340/400mm (Long) cards
IEEE 1101.10 Mechanics for VME Boards and Subracks
IEEE 1101.11 Mechanics for Rear Transition Modules

Three card heights are allowed with VME; 3U, 6U, or 9U; a single slot card is 6T wide. Length is either 160mm or 340mm (Norm)
Height is given in 'U' [1U = 43.60mm], Length is given in 'mm', Width is given in 'T' or HP [1HP = 5.08mm [HP: Horizontal Pitch];
Card sizes listed below are one slot or 6T wide
A size CCA dimensions = 3U x 160mm. A 3U Printed Wiring Board [PWB] is 100mm high.
B size CCA dimensions = 6U x 160mm. A 6U Printed Wiring Board [PWB] is 233mm high.
C size CCA dimensions = 6U x 340mm, ... {H x L x W {@ width=6T}
D size CCA dimensions = 9U x 340mm. A 9U Printed Wiring Board [PWB] is 360mm high.
A, B, C, and D are VXI terms. VME normally only references 3U or 6U [dimensions] by a length.

The board thickness for VME cards is 0.063 +/- 0.008 inchs [1.6mm +/- 0.2mm] Thicker or thinner CCAs may not fit in the card guides correctly.
How ever an 0.90 board may work if you mill down the top and bottom [2.5mm] of the card to 0.63 so it fits in the card guides.

A, B, C, and D are VXI terms. VME normally only references 3U or 6U by a length, but the 9U was added a few years ago.
The VMEbus PWB Dimensions [size] or form factor is also called the Euro-card form factor.

Back to the main VMEbus page for additional details including connector types, bus pin outs, and electronic equipment manufacturers and component manufacturers. OEM VME Card Vendors, and products listing is found on the VME Board manufacturers page.

Abstract: Available VME board sizes. What are the VMEbus board formats. Show the different VME Card form factors
Compare the different VMEbus board dimensions. Comparison of VME card lengths and card heights. What is the depth of a VME board.

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