PRIXP425BB Intel, PRIXP425BB Datasheet - Page 58

• Manufacturer Part Number: PRIXP425BB
• Description: IC NETWRK PROCESSR 266MHZ 492BGA
• Manufacturer: Intel

Specifications of PRIXP425BB

• Processor Type: Network
• Features: XScale Core
• Speed: 266MHz
• Voltage: 1.3V
• Mounting Type: Surface Mount
• Package / Case: 492-BGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 869046

Figure 21.
5.5
Intel
Hardware Design Guidelines
58
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
Component Placement on a PCB
Stack Up Selection
Stack-up selection directly affects the trace geometry which, in turn, affects the
characteristic impedance requirement for the printed-circuit board. Additionally, the
“clean,” noise-free-planes design and placement is significantly important as
components run at higher speeds requiring more power. Considerations include:
• Place noisy parts (clock, processor, video, etc.) at least 1.5 – 3 inches away from
• Do not place noisy components close to internal/external cables
• Place high-current components near the power sources.
• Do not share the same physical components (buffers, inverters, etc.) between
• Place clock drivers and receivers such that clock trace length is minimized.
• Place clock generation circuits near a ground stitch location. Place a localized
• Install clock circuits directly on the printed circuit board; not on sockets.
• Clock crystals should lie FLAT against the board to provide better coupling of
• Low-speed, printed-circuit-board construction — for example two-layer boards:
the edge of the printed circuit board.
high-speed and low-speed signals. Use separate parts.
ground plane around the clock circuits and connect the localized plane to system
ground plane.
electromagnetic fields to the board.
— they will pick up the noise and radiate
— Be aware of the peak in-rush surge current into the device pins. This surge
— Advantages:
— Disadvantages:
• Inexpensive
• Manufactured by virtually all printed-circuit-board vendors
• Poor routing density
• Uncontrolled signal trace impedance
current may inject high-frequency switching noise into power planes of the
printed circuit board.
PCB
Analog Circuit
Intel
®
IXP42X product line and IXC1100 control plane processors—General PCB Guide
Medium Frequency
High Frequency
Low Frequency
Components
Document Number: 252817-008US
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December 2007
B2264-01