LP2998MAE/NOPB National Semiconductor, LP2998MAE/NOPB Datasheet - Page 16

• Manufacturer Part Number: LP2998MAE/NOPB
• Description: IC REG TERM DDR-I/DDR-II 8-SOIC
• Manufacturer: National Semiconductor

Specifications of LP2998MAE/NOPB

• Applications: Converter, DDR, DDR2, DDR3
• Voltage - Input: 2.2 V ~ 5.5 V
• Number Of Outputs: 1
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -

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PCB Layout Considerations
1.
2.
3.
4.
The input capacitor for the power rail should be placed
as close as possible to the PVIN pin.
V
at the point where regulation is required. For
motherboard applications an ideal location would be at
the center of the termination bus.
V
either the DIMM or the Chipset. This provides the most
accurate point for creating the reference voltage.
For improved thermal performance excessive top side
copper should be used to dissipate heat from the
SENSE
DDQ
can be connected remotely to the V
should be connected to the V
TT
termination bus
DDQ
rail input at
16
5.
6.
package. Numerous vias from the ground connection to
the internal ground plane will help. Additionally these can
be located underneath the package if manufacturing
standards permit.
Care should be taken when routing the V
avoid noise pickup from switching I/O signals. A 0.1uF
ceramic capacitor located close to the
used to filter any unwanted high frequency signal. This
can be an issue especially if long
V
ceramic capacitor for improved performance. This
capacitor should be located as close as possible to the
V
REF
REF
should be bypassed with a 0.01 µF or 0.1 µF
pin.
SENSE
SENSE
traces are used.
SENSE
can also be
trace to