6

For most low dropout applications the power dissipation

will be less than 12W.

The power in the device is made up of two components:

the power in the output transistor and the power in the

control circuit.

The power in the control circuit is negligible.

The power in the control circuit is equal to:

The power in the output transistor is equal to:

CS-5205 5A Low Dropout Positive Voltage Regulator

The total power is equal to:

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 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 thermally 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.

This is due to the lower maximum junction temperature

in the control section. At power levels above 12W the

temperature gradient will be greater than 25C and the

maximum ambient temperature will be determined by

the power section. In both cases the jumction temperature

is determined by the total power dissipated in the device.