LM2735XSDEVAL National Semiconductor, LM2735XSDEVAL Datasheet - Page 15

• Manufacturer Part Number: LM2735XSDEVAL
• Description: BOARD EVAL LM2735 1.6MHZ 6LLP
• Manufacturer: National Semiconductor

Specifications of LM2735XSDEVAL

• 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: 1.6MHz
• Board Type: Fully Populated
• Utilized Ic / Part: LM2735
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

The datasheet values for these symbols are given so that one
might compare the thermal performance of one package
against another. In order to achieve a comparison between
packages, all other variables must be held constant in the
comparison (PCB size, copper weight, thermal vias, power
dissipation, V
on the package performance, but it would be a mistake to use
these values to calculate the actual junction temperature in
your application.
We will talk more about calculating the variables of this equa-
tion later, and how to eventually calculate a proper junction
temperature with relative certainty. For now we need to define
the process of calculating the junction temperature and clarify
some common misconceptions.
IN
, V
OUT
, Load Current etc). This does shed light
15
R
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•
•
•
•
It would be wrong to assume that the top case temperature is
the proper temperature when calculating
of a package, not just the top side. This document will refer to
a thermal impedance called
impedance associated with just the top case temperature.
This will allow one to calculate the junction temperature with
a thermal sensor connected to the top case.
θJA
Input Voltage, Output Voltage, Output Current, RDSon.
Ambient temperature & air flow.
Internal & External components power dissipation.
Package thermal limitations.
PCB variables (copper weight, thermal via’s, layers
component placement).
value represents the thermal impedance of all six sides
[Variables]:
.
represents a thermal
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value. The