LM2735XMFSLASHNOPB datasheet(39/59 Pages) TI

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VIN

PGND

AGND

VIN

PCB

PGND

COUT

CIN

LM2735, LM2735-Q1

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SNVS485G – JUNE 2007 – REVISED AUGUST 2015

Layout Examples (continued)

The layout guidelines described for the LM2735 Boost-Converter are applicable to the SEPIC Converter.

Figure 45 shows a proper PCB layout for a SEPIC Converter.

Figure 45. SEPIC PCB Layout

10.3 Thermal Considerations

When designing for thermal performance, one must consider many variables:

•

Ambient Temperature: The surrounding maximum air temperature is fairly explanatory. As the temperature

increases, the junction temperature will increase. This may not be linear though. As the surrounding air

temperature increases, resistances of semiconductors, wires and traces increase. This will decrease the

efficiency of the application, and more power will be converted into heat, and will increase the silicon junction

temperatures further.

•

Forced Airflow: Forced air can drastically reduce the device junction temperature. Air flow reduces the hot

spots within a design. Warm airflow is often much better than a lower ambient temperature with no airflow.

•

External Components: Choose components that are efficient, and you can reduce the mutual heating

between devices.

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LM2735XMF/NOPB 数据表(PDF) 39 Page - Texas Instruments