Micrel, Inc.
capacitor of at least 1µF is needed directly between the
input and regulator ground. Refer to “Application
Note 9”
for further details and examples on thermal design and
heat sink specifications.
The maximum power allowed can be calculated using
the thermal resistance (θ
JA
) of the D-Pak adhering to the
following criteria for the PCB design: 2 oz. copper and
100mm
2
copper area for the MIC47150. Given a
maximum ambient temperature (T
A
=75°C), and without
the use of a heat sink, the maximum power allowed that
would not exceed the
temperature (125°C) is
IC’s
MIC47150
maximum
junction
P
D(MAX)
= (T
J(MAX)
– T
A
)/θ
JA
= (125°C – 75°C)/(56°C/W)
= 0.893W
Minimum Load Current
The MIC47150, unlike most other high current
regulators, does not require a minimum load to maintain
output voltage regulation.
October 2009
8
M9999-102309-A
MICREL [ MICREL SEMICONDUCTOR ]
