LP3981 datasheet(8/11 Pages) NSC

8 / 11 page

Typical Performance Characteristics Unless otherwise specified, C

IN =COUT = 2.2 µF Ceramic,

CBP = 0.033 µF, VIN =VOUT + 0.5V, TA = 25˚C, Enable pin is tied to VIN. (Continued)

Line Transient Response

IN =VOUT +1VtoVOUT + 1.6V)

Line Transient Response

IN =VOUT +1VtoVOUT + 1.6V)

20020326

20020327

Line Transient Response

IN =VOUT +1VtoVOUT + 1.6V)

Line Transient Response

IN =VOUT +1VtoVOUT + 1.6V)

20020328

20020329

Enable Response (T

ON)

Enable Response (T

ON)

20020330

20020331

Application Hints

POWER DISSIPATION AND DEVICE OPERATION

The permissible power dissipation for any package is a

measure of the capability of the device to pass heat from the

power source, the junctions of the IC, to the ultimate heat

sink, the ambient environment. Thus, the power dissipation

is dependant on the ambient temperature and the thermal

resistance across the various interfaces between the die and

ambient air.

As stated in notes 3 and 5 in the electrical specifications

sections, the allowable power dissipation for the device in a

given package can be calculated using the equation:

With a

JA = 50˚C/W, the device in theLLP package returns

a value of 2.0W with a maximum junction temperature of

LP3981 Fiches technique(PDF) 8 Page - National Semiconductor (TI)