THS6032_14 Datasheet, PDF (15/35 Pages) Texas Instruments – LOW-POWER ADSL CENTRAL-OFFICE LINE DRIVER

THS6032
www.ti.com....................................................................................................................................................... SLOS233F – APRIL 1999 – REVISED AUGUST 2009
The THS6032 is also available in the MicroStar Junior GQE package. Just like the DWP and VFP packages, the
GQE package utilizes the PowerPAD functionality to improve thermal performance. The GQE package is part of
the new ball-grid array (BGA) family developed by Texas Instruments (TI). This package allows for even
higher-density layouts with virtually no loss in thermal performance. Its construction is similar to the DWP and
VFP construction [see Figure 39 (a) and (b)], but uses the terminal balls to transfer the heat away from the die.
(TOP VIEW)
(Side VIEW)
Die
(a)
(b)
NOTE: Shaded areas are part of the thermally-conductive path.
Figure 39. Views of Thermally-Enhanced GQE Package
The PowerPAD packages allows for both assembly and thermal management in one manufacturing operation.
During the surface-mount solder operation (when the leads or balls are being soldered), the thermal areas can
also be soldered to a copper area underneath the package. Through the use of thermal paths within this copper
area, heat can be conducted away from the package into either a ground plane or other heat dissipating device.
This is discussed in more detail in the PCB design considerations section of this document.
The PowerPAD package represents a breakthrough in combining the small area and ease of assembly of
surface mount with the, heretofore, awkward mechanical methods of heat sinking.
Because of its power dissipation, proper thermal management of the THS6032 is required. There are several
ways to properly heat sink all three PowerPAD packages. There are several TI application notes on how to best
accomplish the thermal mounting scheme required for each package. For the DWP and VFP packages, refer to
the Texas Instruments Technical Brief, PowerPAD Thermally-Enhanced Package (SLMA002). There is also a
more compact technical paper entitled PowerPad Made Easy (SLMA004). For the GQE – MicroStar Junior
package, refer to the MicroStar BGA Packaging Reference Guide (SSYZ015A) and the compact version entitled
MicroStar Junior Made Easy (SSYA009). This literature is available on TI's web site at http://www.ti.com.
The actual thermal performance achieved with the THS6032 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, θ_JA, is about 21.5°C/W for the DWP package, 37.8°C/W for the GQE
package, and 30°C/W for the VFP package. Although the maximum recommended junction temperature (T_J) is
listed as +150°C, performance at this elevated temperature will suffer. To ensure optimal performance, the
junction temperature should be kept below +125°C. Above this temperature, distortion will tend to increase.
Figure 40 shows the recommended power dissipation with a junction temperature of +125°C. Also shown is what
happens if no solder is used to solder the PowerPAD to the PCB. The θ_JA increases dramatically with a vast
reduction in power dissipation. For a given θ_JA and a maximum junction temperature, the power dissipation is
calculated by the following formula:
ǒ Ǔ PD +
TMAX–TA
q_JA
(1)
Where:
P_D = Power dissipation of THS6032 (watts)
T_MAX = Maximum junction temperature allowed in the design (+125°C recommended)
T_A = Free-ambient air temperature (°C)
θ_JA = θ_JC + θ_CA
θ_JC = Thermal coefficient from junction to case (DWP = 0.37°C/W, GQE = 4.56°C/W, VFP = 1.2°C/W)
θ_CA = Thermal coefficient from case to ambient
Copyright © 1999–2009, Texas Instruments Incorporated
Product Folder Link(s): THS6032
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