This document summarizes the design of a dense memory module (DMM) connector. It includes designs for a 32-connector array atop a motherboard with pin-socket-BGA interconnects below. Stress analysis was performed on contact prototypes to minimize stress concentrations and ensure the tapered beam design uniformly distributes stress along the contact length. The final DMM module design integrated these contacts and interconnects within a 1U chassis to provide a high-density memory solution.

1. Dense Memory Module
Advanced Interconnect Design Project
By
Mike Ryland

2. Custom Edge Card Connector shown
with 82 Beam style contacts

3. Connector - Card Interface

4. Contact to Pad Alignment Challenge

5. Edge Card Connector Concept Design

6. DMM Connector Configuration
32 Connector Array on top of Motherboard

7. DMM Connector Configuration
Top View

8. DMM Connector Configuration
Bottom of Mother board (Pin Array)

9. Pin Socket Interconnect Array
Bottom of mother board

10. Pin-Socket-BGA/LGA Array Interconnects

11. DMM Board Thermal Management

12. 1U Chasis and DMM Module Detail

13. Contact Detail Design

14. Contact Detail Design cont.

15. Contact Detail Design cont.

16. Housing Detail Design

17. Housing Detail Design cont.

18. Housing Detail Design cont.

19. Contact to Housing Tolerance Analysis

20. Contact to Housing Tolerance Analysis cont.

21. Connector Prototype

22. Contact Prototypes

23. Contact Prototypes

24. PERMANENT SET AFTER .015 DEFLECTION

25. MAX RESIDUAL STRESS, K000029902
NORMAL FORCE, BENDING STRESS AND PERMANENT SET

26. MAX STRESS (Uniform Distribution)
 TAPERED BEAM UNIFORMELY
DISTRIBUTES STRESS ALONG THE
LENGTH OF THE CONTACT/BEAM.
 MINIMIZE LOCAL STRESS
CONCENTRATIONS, UTILIZING FULL
LENGTH OF BEAM TO DISTRIBUTE
STRESS.
 NORMAL FORCE 5.3 GRAMS PER
CONTACT
• MAX STRESS/DEFLECTION OCCURS AT STEP 10 OF 26,
1.528 SECONDS INTO THE 4.2 SECOND SIMULATION
USING A PARABOLIC LOADING/UNLOADING CURVE.
• STEPS ARE .042 SECONE INCREMENTS.

27. STRESS DISTRIBUTION (cont).
ANIMATION DEMONSTRATING
ONE COMPLETE CYCLE OF
“LOADING-UNLOADING”
 TAPERED BEAM
UNIFORMELY DISTRIBUTES
STRESS ALONG THE LENGTH
OF THE CONTACT/BEAM.
 MINIMIZE LOCAL STRESS
CONCENTRATIONS,
UTILIZING FULL LENGTH OF
BEAM TO DISTRIBUTE
STRESS.
 NORMAL FORCE 5.3
GRAMS PER CONTACT
• MAX STRESS/DEFLECTION OCCURS AT STEP
10 OF 26, 1.528 SECONDS INTO THE 4.2
SECOND SIMULATION USING A PARABOLIC
LOADING/UNLOADING CURVE.
• STEPS ARE .042 SECONE INCREMENTS.
Animation
Press Play button to see animation

29. MAX FIBRE/SURFACE STRESSES
TENSION (+) AND COMPRRESSIVE (-) STRESSES

30. SETUP AND ASSUMPTIONS
 INPUT CURVE –
LOADING/UNLOADING
CYCLE
 .015 PRESCRIBED
DISPLACEMENT
 NO “FIXED” CONSTRAINTS
WERE USED.
 “ROLLER/SLIDER” AND
REFERENCE GEOMETRY/
SYMMETRY WAS USED TO
MAKE SIMULATIONS AS
REALISTIC AS POSSIBLE.

31. Solder Tab K000029903
STRESS ANALYSIS

32. DEFLECTION

33. Final DMM Module