Mobile Intel Pentium 4 Processor - M and Intel 845MP/MZ Chipset Platform Design Guide

ManualsBrandsIntel ManualsOtherIntel Pentium 4 Processor supporting HT Technology 3.00E GHz, 1M Cache, 800 MHz FSB

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Mobile Intel

Pentium

4 Processor-M and Intel

845MP/845MZ Chipset Platform

Design Guide 133

9.10.3.2. Power and Ground Connections

Some rules to follow for power and ground connections:

• For best performance place decoupling capacitors on the backside of the PCB directly under the

82562EH with equal distance from both pins of the capacitor to power/ground.

• The analog power supply pins for 82562EH (VCCA, VSSA) should be isolated from the digital

VCC and VSS through the use of ferrite beads. In addition, adequate filtering and decoupling

capacitors should be provided between VCC and VSS, and VCCA, and VSSA power supplies.

9.10.3.3. Guidelines for 82562EH Component Placement

Component placement can affect signal quality, emissions, and temperature of a board design. This

section will provide guidelines for component placement.

Careful component placement can:

• Decrease potential problems directly related to electromagnetic interference (EMI), which could

cause failure to meet FCC specifications.

• Simplify the task of routing traces. To some extent, component orientation will affect the

complexity of trace routing. The overall objective is to minimize turns and crossovers between

traces.

Minimizing the amount of space needed for the HomePNA* LAN interface is important because all other

interface will compete for physical space on a motherboard near the connector edge. As with most

subsystems, the HomePNA* LAN circuits need to be as close as possible to the connector. Thus, it is

imperative that all designs be optimized to fit in a very small space.

9.10.3.4. Crystals and Oscillators

To minimize the effects of EMI, clock sources should not be placed near I/O ports or board edges.

Radiation from these devices may be coupled onto the I/O ports or out of the system chassis. Crystals

should also be kept away from the HomePNA* magnetic module to prevent interference of

communication. The retaining straps of the crystal (if they should exist) should be grounded to prevent

possibility radiation from the crystal case and the crystal should lay flat against the PC board to provide

better coupling of the electromagnetic fields to the board.

For a noise free and stable operation, place the crystal and associated discretes as close as possible to

82562EH, keeping the length as short as possible and do not route any noisy signals in this area.

9.10.3.5. Phoneline HPNA Termination

The transmit/receive differential signal pair is terminated with a pair of 51.1-Ω (1%) resistors. This

parallel termination should be placed close to the 82562EH. The center, common point between the 51.1-

Ω resistors is connected to a voltage divider network. The opposite end of one 806-Ω resistor is tied to

VCCA (3.3 V), and the opposite end of the other 806-

Ω resistor and the cap are connected to ground.

The termination is shown in the following figure.