During board-to-board insertion and removal, the installation process should work within the
following recommended strain limits. The following figure shows the recommended locations (E–
W, N–S) for a strain measurement on a carrier card. Diagonal strain should not exceed 500 micro-
strain during mating. Strain rate duration taken to reach maximum 500 micro-strain should not be
less than four seconds. Based on experimental data, the maximum strain of 428 micro-strain
reached in 3.63 seconds duration and was validated through dye and pry, where the sample
passed.
Figure 5: Recommended Locations for Strain Measurement on a Carrier Card
Board to Board Connector Distance Tolerance
Control
The distance between the mating ADM6 connectors on the carrier card must match the distance
between the ADF6 connectors on the SOM. The final connector position is dictated by auto-
placement machine accuracy and PCB pad position tolerance. The way the distance is measured
between connectors is crucial to ensure seamless board-to-board mating, without applying
mechanical stress.
Chapter 3: Mechanical Design Considerations
UG1091 (v1.0) April 20, 2021
Carrier Card Design for Kria SOM
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