LP2967 Datasheet, PDF (16/20 Pages) National Semiconductor (TI) – Dual Micropower 150 mA Low-Dropout Regulator in micro SMD Package

Application Hints (Continued)
MAXIMUM POWER DISSAIPATION CAPABILITY
Each output pin the LP2967 can deliver a current of up to
150mA over the full operating junction temperature range.
However, the maximum output current must be derated at
higher ambient temperature to ensure the junction tempera-
ture does not exceed 125˚C. Under all possible conditions,
the junction temperatures must be within the range specified
under operating conditions. The LP2967 is available in
MSOP-8 package and 8-bump micro SMD. The junction to
ambient temperature coefficient (θ_JA) for an MSOP-8 pack-
age is 235˚C/W and the 8-bump micro SMD with minimum
copper area is 220˚C/W. The total power dissipation of the
device is given by:
PD = (V_IN − V_OUT1) I_OUT1 + (V_IN − V_OUT2) I_OUT2
The maximum power dissipation, PDmax, that the device
can tolerate can be calculated by using the formula:
PDmax = (T_JMAX − T_A) / θ_JA
where T_JMAX is the maximum specified junction temperature
(125˚C), and T_A is the maximum ambient temperature.
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