Verdin Carrier Board Design Guide
Preliminary
– Subject to Change
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4
Mechanical and Thermal Consideration
4.1
Module Connector and Stacking Height
The Verdin module uses the SODIMM DDR4 memory module edge connector. This connector has
260 pins with a 0.5mm pitch. Suitable connectors are available from different manufacturers in
various board-to-board stacking heights. Manufacturers such as Amphenol or TE Connectivity use
the term stacking height for the overall height of the connector. This is not the actual distance
between the module and the carrier board like with board to board connectors. Amphenol and TE
Connectivity provide four different connector heights from 4mm to 9.2mm.
The following table compares the different options. The connector height is the total height of the
connector that can also be found in the name of the connector. The board-to-board distance is the
nominal space between the carrier board and the module. Please note that in worst case
situations, this distance can be smaller. The column “Component Height Carrier Board” indicates
the recommended maximum height of components underneath the module. Close to the SODIMM
connector, there is an area which allows for higher components such as decoupling capacitors or
series resistors to be placed. The maximum height in this area is listed in the column “Component
Height Carrier Board (next to connector)”.
Connector
Height
Board-to-
board distance
Component Height
Carrier Board
Component Height
Carrier Board
(next to connector)
Remarks
4 mm
1.52 mm
Connector not suitable for Verdin modules due to
the too small board-to-board distance
5.2 mm
2.62 mm
0 mm
0.8 mm
Recommended stacking height for Verdin modules
8 mm
5.42 mm
2.8 mm
3.6 mm
9.2 mm
6.62 mm
4 mm
4.8 mm
Table 39: SODIMM Connector Stacking Height
There are also reverse angle connectors available. These connectors are not recommended for
modules that require a cooling solution. Toradex recommends using the TE Connectivity 2309409-
2 which has a connector height of 5.2mm that provides a board-to-board distance of 2.62mm.
The Verdin module does not follow the JEDEC specifications which allow only a maximum of 1.2
mm for components on the top and bottom side of the module. The components on the top side of
the Verdin module are limited to 3.0 mm height while the absolute maximum height for
components placed on the bottom side is limited to 2.0 mm, except for an area next to the edge
connector in which the module components are limited to 1.2 mm height. This allows for an extra
0.8 mm for decoupling capacitors and series resistors on the carrier board.
