MIC5528 Datasheet, PDF (9/14 Pages) Micrel Semiconductor – High-Performance 500mA LDO

Micrel, Inc.
Substituting P_D for P_D(max) and solving for the ambient
operating temperature will give the maximum operating
conditions for the regulator circuit. The junction-to-
ambient thermal resistance for the minimum footprint is
173°C/W.
The maximum power dissipation must not be exceeded
for proper operation.
For example, when operating the MIC5528-3.3YMX at an
input voltage of 3.6V and a 500mA load with a minimum
footprint layout, the maximum ambient operating
temperature T_A can be determined as in Equation 4:
0.15W = (125°C − T_A )/(173°C / W )
T_A = 99°C
Eq. 4
Therefore, the maximum ambient operating temperature
allowed in a thermally enhanced 1.2mm × 1.2mm XTDFN
package is 99°C. 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
MIC5528
May 5, 2014
9
Revision 1.1