5A L.D.O. VOLTAGE REGULATOR (Adjustable & Fixed)
THERMAL CONSIDERATIONS
LM1084
The LM1084 series have internal power and thermal limiting circuitry designed to protect the device under
overload cinditions. However maximum junction temperature ratings should not be exceeded under continous
normal load conditions.
Careful consideration must be given to all sourses of thermal resistance from junction to ambient, including
junction-to- ase, case-to-heat sink interface and heat sink resistance itself. To ensure safe operating
temperatures and reflect more accurately the device temperature, new thermal resistance specifications have
been developed. Unlike order reguators with a single junction-to-case thermal resistance speccification, the
data section for these new regulators provides a separate thermal resistance and maximum juntion temperature
for both the Control Section and the Power Transistor. Calculations for both temperatures under certain
conditions of ambient temperature and heat sink resistance and to ensure that both thermal limits are met.
Junction-to-case thermal resistance is specified from the IC junction to the bottom of the case directly below
the die. This is the lowest resistance path for the heat flow. In order to ensure the best possible thermal flow
from this area of the package to the heat sink proper mounting is required. Thermal compound at the case-
to-heat sink interface is recommended. A thermarlly conductive spacer can be used, if the case of the device
must be electrically isolated, but its added contribution to thermal resistance has to be considered.
HTC
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HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
