Intel Pentium 4 Processor 423 Pin Socket (PGA423) Design Guidelines

423 Pin Socket Design Guidelines

Every Rtotal will be applied to equations 1-3, where the Rjumper in the

following equations comes from a statistical average of many measurements.

The resistance requirement, Rreq, can be calculated for each chain with the

measurements as shown in the following equations.

From To

Pin# Pin#

C35 AR5 Rreq = (Rtotal – Rjumper) / 108 pins (equation 1)

AV38 AV4 Rreq = (Rtotal – Rjumper) / 88 pins (equation 2)

B34 AN3 Rreq = (Rtotal – Rjumper) / 178 pins (equation 3)

4.1.1. Determination of Maximum Electrical Resistance:

As in Section 4.1, measure the following pin-to-pin configurations on a good

number of packages flush mounted to motherboard fixtures to get a statistical

average for Rjumper. Measure the same configurations to get Rtotal with the

package fixture mounted on the socket, which is mounted on a motherboard

fixture. All of the following pin pairs will be measured, and the Rreq of

equation 4 must be satisfied for every measured socket.

Pin Pairs.

B2-C3 B38-D38 AV2-AV4 AU35-AU37

C1-D2 A37-C37 AU3-AU5 AW19-AW21

B4-A5 E39-G39 AW39-AU39 U39-W39

B6-C7 AW1-AU1 AW35-AW37 B20-A21

A39-C39 AW3-AW5 AV34-AV36 W1-Y2

Rreq = (Rtotal – Rjumper) / 2 pins (equation 4)

4.1.2. Initial/Final Electrical Resistance:

The electrical resistance is for the socket plus the part of the engaged package

pin inside the socket. The final electrical resistance refers to the resistance

measured after all the environmental testing such as shock and vibration has

been conducted. (See Section 5.)

There are two requirements:

(1) Final electrical resistance, Rreq from equations 1 - 3, shall not exceed

12mΩ.

(2) No single pin, Rreq from equation 4, shall exceed the electrical resistance

of 17mΩ.