Electrical Requirements
4.1Electrical Resistance
Figure 4-1and Figure 4-2show the proposed methodology for measuring the final electrical resistance. The methodology requires measuring interposer flush-mounted directly to the motherboard fixtures, so that the pin shoulder is flush with the motherboard, to get the averaged jumper resistance, Rjumper. The Rjumper should come from a good statistical average of 30 package fixtures flush mounted to a motherboard fixture. The same measurements are then made with a package fixture mounted on a supplier’s socket, and both are mounted on a motherboard
fixture; this provides the RTotal. The resistance requirement, RReq, can be calculated for each chain as will be explained later.
Figure 4-1. Methodology for Measuring Total Electrical Resistance
Interposer | Socket Contact | Shorting Bar |
|
| | | | |
| | | | |
Interposer Shoulder
Interposer Pin
Figure 4-2. Methodology for Measuring Electrical Resistance of the Jumper
Interposer | Shorting Bar |
| Interposer Shoulder |
+V | -V |
+I | -I |
|
| Motherboard |
Figure 4-3shows the resistance test fixtures separately and superimposed. The upper figure is the package. The next figure is the baseboard. There are 48 daisy chain configurations on resistance test board. The bottom figure is the two parts superimposed. Table 4-3shows these configurations with the number of pins per each chain and netlist.
20 | mPGA604 Socket Design Guidelines |
