TLD4012 Datasheet, PDF (11/13 Pages) Tripath Technology Inc. – ADSL LINE DRIVER USING TRIPATH DIGITAL POWER PROCESSING (DPP™) TECHNOLOGY

Tripath Technology, Inc. - Technical Information
APPLICATION INFORMATION
Power Dissipation Derating for 5x5mm TQFP with Exposed Die Pad
For operating at ambient temperatures above 25°C the device power dissipation, P_DISS, must be de-rated
based on a 150°C maximum junction temperature T_J (max) as given by the following equation:
P_DISS = (T_J(max) – T_A)/θ_JA
Where θ_JA of the package is determined from the table, and T_A is the ambient temperature.
Airflow
(LFPM)
0
200
500
θ_JA,C/W
(Copper Pad Soldered To PCB)
5x5mm
34.5
29.1
27.2
Values apply when the exposed pad is soldered to a JEDEC standard test board.
Note that P_DISS is the power dissipated on the chip, not P_CONS which is the power consumed from the
supplies.
The TLD4012 incorporates an exposed die pad on the underside of its package. This acts as a heat sink
and should be connected to a copper plane on the printed circuit board for optimum heat dissipation. This
copper plane must be connected to VSS15.
11
TLD4012 – JB/Rev. 2.0a/05.02