LP2998MA/NOPB National Semiconductor, LP2998MA/NOPB Datasheet - Page 14

• Manufacturer Part Number: LP2998MA/NOPB
• Description: IC REG TERM VOLT DDRI/II 8-SOIC
• Manufacturer: National Semiconductor

Specifications of LP2998MA/NOPB

• Applications: Converter, DDR, DDR2, DDR3
• Voltage - Input: 2.2 ~ 5.5 V
• Number Of Outputs: 1
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Primary Input Voltage: 2.5V
• No. Of Outputs: 1
• No. Of Pins: 8
• Output Current: 1.5A
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 1 - Unlimited
• Input Voltage Primary Max: 5.5V
• Rohs Compliant: Yes
• For Use With: LP2998EVAL - BOARD EVALUATION FOR LP2998
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Other names: LP2998MA

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LEVEL SHIFTING
If standards other than SSTL-2 are required, such as SSTL-3,
it may be necessary to use a different scaling factor than 0.5
times V
are available to scale the output to any voltage required. One
method is to level shift the output by using feedback resistors
Conversely, the R2 resistor can be placed between V
and V
ence voltage of VDDQ/2. The equation relating to VTT and
the resistors can be used as shown:
HSTL APPLICATIONS
The LP2998 can be easily adapted for HSTL applications by
connecting V
DDQ
DDQ
to shift the V
for regulating the output voltage. Several options
DDQ
to the 1.5V rail. This will produce a V
TT
output lower than the internal refer-
FIGURE 9. Decreasing VTT by Level Shifting
FIGURE 8. Increasing VTT by Level Shifting
FIGURE 10. HSTL Application
TT
SENSE
and
14
from V
8
level shift V
2. To calculate the exact voltage at V
can be used.
V
sistors. AVIN and PVIN should be connected to a 2.5V rail for
optimal performance.
REF
and
voltage of approximately 0.75V for the termination re-
TT
Figure
to the V
TT
9.
above the internal reference voltage of VDDQ/
Figure 8
SENSE
V
V
TT
TT
30026916
= VDDQ/2 (1 + R1/R2)
= VDDQ/2 (1 - R1/R2)
30026915
pin. This has been illustrated in
shows how to use two resistors to
30026917
TT
the following equation
Figure