MIC5301 Datasheet, PDF (9/11 Pages) Micrel Semiconductor – Single, 150mA μCap ULDO™

Micrel, Inc.
To determine the maximum ambient operating
temperature of the package, use the junction-to-
ambient thermal resistance of the device and the
following basic equation:
⎛ ^TJ(MAX) ^{- T}A
⎝ ^{PD(MAX) =}
JA
T_J(max) = 125°C, the maximum junction temperature of
the die θ_JA thermal resistance = 100°C/W.
The table below shows junction-to-ambient thermal
resistance for the MIC5301 in the 6-pin 1.6mm x
1.6mm MLF^® package.
Package
6-Pin 1.6x1.6 MLF^®
θ_JA Recommended
Minimum Footprint
100°C/W
Thermal Resistance
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 100°C/W.
MIC5301
The maximum power dissipation must not be
exceeded for proper operation.
For example, when operating the MIC5301-2.8YML at
an input voltage of 5V and 150mA load with a
minimum footprint layout, the maximum ambient
operating temperature T_A can be determined as
follows:
0.33W = (125°C – T_A)/(100°C/W)
T_A=92°C
Therefore, a 2.8V application with 150mA of output
current can accept an ambient operating temperature
of 92°C in a 1.6mm x 1.6mm MLF^® 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
November 2006
9
M9999-111506