LM2735YMYEVAL National Semiconductor, LM2735YMYEVAL Datasheet - Page 21
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LM2735YMYEVAL
Manufacturer Part Number
LM2735YMYEVAL
Description
BOARD EVAL LM2735 520KHZ 8MSOP
Manufacturer
National Semiconductor
Specifications of LM2735YMYEVAL
Main Purpose
DC/DC, Step Up
Outputs And Type
1, Non-Isolated
Voltage - Output
12V
Current - Output
500mA
Voltage - Input
3 ~ 5.5V
Regulator Topology
Boost
Frequency - Switching
520kHz
Board Type
Fully Populated
Utilized Ic / Part
LM2735
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
-
Steady State Analysis with Loss
Elements
Using inductor volt-second balance & capacitor charge bal-
ance, the following equations are derived:
Therefore:
One can see that all variables are known except for the duty
cycle (D). A quadratic equation is needed to solve for D. A
less accurate method of determining the duty cycle is to as-
sume efficiency, and calculate the duty cycle.
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SEPIC Converter PCB Layout
The layout guidelines described for the LM2735 Boost-Con-
verter are applicable to the SEPIC Converter. Below is a
proper PCB layout for a SEPIC Converter.
Efficiencies for Typical SEPIC Application
FIGURE 17. SEPIC PCB Layout
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