MIC5305 Datasheet, PDF (10/12 Pages) Micrel Semiconductor – 150mA UCap Ultra-Low Dropout LDO Regulator

MIC5305
Table 1 shows junction-to-ambient thermal resistance for the
MIC5305 in the 2mm × 2mm MLF™-6 package.
Package
θ_JA Recommended
θ_JC
Minimum Footprint
2 × 2 MLF™-6
93°C/W
2°C/W
Table 1. SOT-23-5 Thermal Resistance
Substituting P_D for P_D(max) and solving for the ambient
operating temperature will give the maximum operating con-
ditions for the regulator circuit. The junction-to-ambient ther-
mal resistance for the minimum footprint is 93°C/W, from
Table 1. The maximum power dissipation must not be ex-
ceeded for proper operation.
For example, when operating the MIC5305-2.9BML at an
input voltage of 5.0V and 150mA load with a minimum
footprint layout, the maximum ambient operating tempera-
ture T_A can be determined as follows:
0.32W = ^{125°C − TA}
93°C/W
Micrel
T_A = 95.2°C
Therefore, a 2.9V application at 150mA of output current can
accept an ambient operating temperature of 95.2°C in a 2mm
x 2mm MLF™-6 package. For a full discussion of heat sinking
and thermal effects on voltage regulators, refer to the “Regu-
lator 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
August 2004
10
M9999-081704