LM20134EVAL National Semiconductor, LM20134EVAL Datasheet - Page 5

• Manufacturer Part Number: LM20134EVAL
• Description: BOARD EVAL 4A POWERWISE LM20134
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM20134EVAL

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.2V
• Current - Output: 4A
• Voltage - Input: 2.95 ~ 5.5V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: LM20134
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Power - Output: -
• Frequency - Switching: -

response can be optimized by reducing the value of C
calculating the value for R
R
Once the value of C
a zero in the control loop to cancel the output filter pole. This
resistor can be sized according to the equation:
For stability purposes the device should be compensated for
the maximum output current expected in the application.
C
A second compensation capacitor C
designs to provide a high frequency pole, useful for cancelling
a possible zero introduced by the ESR of the output capacitor.
For the LM20134 evaluation board, the C
populated, as the low ESR ceramic capacitor used on the
output does not contribute a zero to the control loop before
the crossover frequency. If the ceramic capacitor on the eval-
C1
C2
C1
is known, resistor R
C1
as outlined in the next section.
C2
can be used in some
C1
C2
is used to place
footprint is un-
C1
and
5
uation board is replaced with a different capacitor having
significant ESR, the required value of the capacitor C
be estimated by the equation:
R
The resistors labeled R
from V
the voltage regulator. Nominally, the output of the LM20134
evaluation board is set to 1.2V, giving resistor values of
R
is required, the value of R
equation:
R
FB1
FB1
FB2
= 4.99 kΩ and R
does not need to be changed from its value of 10 kΩ.
and R
OUT
to the feedback pin that is used to set the output of
FB2
FB2
FB1
= 10 kΩ. If a different output voltage
FB1
and R
can be adjusted according to the
FB2
create a voltage divider
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C2
can