P

D +

T

MAX

–T

A

q

JA

Where:

PD

= Maximum power dissipation of THS6012 (watts)

TMAX = Absolute maximum junction temperature (150°C)

TA

= Free-ambient air temperature (

°C)

θJA = θJC + θCA

θJC = Thermal coefficient from junction to case (0.37°C/W)

θCA = Thermal coefficient from case to ambient

0.1025

0.080

0.178

0.026

0.024

0.021

0.0165

0.450

0.476

.039

0.026

0.120

0.085

PowerPAD and via placement

pad area (0.085 x 0.120) with 15

vias (Via diameter = 0.013)

Vias should go through the board connecting the top layer

PowerPad to any and all ground planes. (The larger the ground

plane, the larger the area to distribute the heat.) Solder resist should

be used on the bottom side ground plane in order to prevent wicking

of the solder through the vias during the reflow process.

All Units in Inches

THS6012

SLOS226F – SEPTEMBER 1998 – REVISED JUNE 2012

www.ti.com

reflow operation as any standard surface-mount component. This results in a part that is properly installed.

Figure 45. PowerPAD PCB Etch and Via Pattern

The actual thermal performance achieved with the THS6012 in its PowerPAD package depends on the

application. In the previous example, if the size of the internal ground plane is approximately 3 inches × 3 inches,

then the expected thermal coefficient,

ΘJA, is about 21.5°C/W. For a givenΘ JA, the maximum power dissipation

is shown in Figure 46 and is calculated by the following formula:

More complete details of the PowerPAD installation process and thermal management techniques can be found

in the Texas Instruments Technical Brief, PowerPAD Thermally Enhanced Package. This document can be found

at the TI web site (www.ti.com) by searching on the key word PowerPAD. The document can also be ordered

through your local TI sales office. Refer to literature number SLMA002 when ordering.

24

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