MIC5375/6/7/8: High Performance Low Dropout 150mA LDO - Micrel - #9

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Micrel, Inc. MIC5375/6/7/8 January 2009 9 M9999-011309-B Substituting PD for PD(max) and solving for the ambient operating temperature will give the maximum operating conditions for the regulator circuit. The junction-toambient thermal resistance for the minimum footprint is 250°C/W. The maximum power dissipation must not be exceeded for proper operation. For example, when operating the MIC5375-2.8YMT at an input voltage of 3.6V and 150mA load with a minimum footprint layout, the maximum ambient operating temperature TA can be determined as follows: 0.12W = (125°C – TA)/(250°C/W) TA = 95°C Therefore the maximum ambient operating temperature of 95°C is allowed in a 1mm x 1mm TMLF® package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the “Regulator Thermals” section of Micrel’s Designing with Low-Dropout Voltage Regulators handbook. This information can be found on Micrel's website at: http://www.micrel.com/_PDF/other/LDOBk_ds.pdf