Schematic Review Checklist
R
258 Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide
Checklist Items Recommendations Reason/Impact
1.4 V (RAMREF)
decoupling
(300/400 MHz
RDRAM
technology)
1.35 V (RAMREF)
decoupling (533
MHz RDRAM
technology)
This plane must be decoupled in the
following manner:
• Each RIMM connector: Locally – A
value of 0.1
µF is required for local
decoupling.
• RAMREF Generation Circuit: At
resistor divider – The RAMREF
generation circuitry should be placed
near the MCH. A 75
Ω ±2% pull-up
resistor and 300
Ω ±2% pull-down
resistor is required for proper
reference voltage (1.4V) in 300/400
MHz RDRAM* technology systems.
An 84.5
Ω ±2% pull-up resistor and
255
Ω ±2% pull-down resistor is
required for proper reference voltage
(1.35V) in 533 MHz RDRAM*
technology systems.
• MCH: Locally – A value of 0.1 µF is
required for local decoupling and a
100
Ω series resistor is required near
the MCH, but before the voltage
divider circuit.
• Refer to Section 6.1.4.
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