LMZM23600

Layout Guidelines (continued)

As an example, consider a typical application of 24-V input 5-V output with 0.5 A of output current and estimate the required heat-sinking area. For this example consider a maximum ambient temperature TA_MAX of 95°C and no air flow or additional heat sinking besides the PCB layers. Calculate the maximum allowed package thermal resistance for this design specification.

From Typical Characteristics, it can be seen that the power dissipation for 24-V input, 5-V output, and 0.5A load is 0.4 W. Based on Equation 7, for this power dissipation level and 95°C maximum ambient temperature, the maximum package thermal resistance must be less than 75°C/W. To achieve this thermal resistance with a 2- layer board, the approximate area of the board copper should be at least 5 cm2.

11.2 Layout Examples

Figure 82. Layout Example With Fixed Output Version

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LMZM23600

Layout Examples (continued)

Figure 83. Layout Example With Adjustable Output Version

Product Folder Links: LMZM23600