Datasheet
POWER DISSIPATION AND THERMAL
P =
DMax
T T
Max
-
A
q
JA
θ
JA
= 58.4°C/W for 8-Pin MSOP w/PowerPad (DGN)
θ
JA
= 98°C/W for 8-Pin SOIC High Test PCB (D)
θ
JA
= 158°C/W for 8-Pin MSOP w/PowerPad w/o Solder
Results are With No Air Flow and PCB Size = 3”x3”
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
-40 -20 0 20 40 60 80 100
P
D
- Maximum Power Dissipation - W
T
A
- Free-Air Temperature - °C
θ
JA
= 98°C/W
θ
JA
= 158°C/W
T
J
= 125°C
θ
JA
= 58.4°C/W
THS3201
www.ti.com
............................................................................................................................................................. SLOS416C – JUNE 2003 – REVISED JUNE 2009
being pulled away from the thermal pad area For systems where heat dissipation is more critical,
during the reflow process. the THS3201 is offered in an 8-pin MSOP with
PowerPAD and also available in the SOIC-8
7. Apply solder paste to the exposed thermal pad
PowerPAD package, offering even better thermal
area and all of the IC terminals.
performance. The thermal coefficients for the
8. With these preparatory steps in place, the IC is
PowerPAD packages are substantially improved over
simply placed in position and run through the
the traditional SOIC. Maximum power dissipation
solder reflow operation as any standard
levels are depicted in the graph for the available
surface-mount component. This results in a part
packages. The data for the PowerPAD packages
that is properly installed.
assume a board layout that follows the PowerPAD
layout guidelines referenced above and detailed in
the PowerPAD application note number SLMA002 .
CONSIDERATIONS
The following graph also illustrates the effect of not
soldering the PowerPAD to a PCB. The thermal
To maintain maximum output capabilities, the
impedance increases substantially which may cause
THS3201 does not incorporate automatic thermal
serious heat and performance issues. Be sure to
shutoff protection. The designer must take care to
always solder the PowerPAD to the PCB for optimum
ensure that the design does not violate the absolute
performance.
maximum junction temperature of the device. Failure
may result if the absolute maximum junction
temperature of +150 ° C is exceeded. For best
performance, design for a maximum junction
temperature of +125 ° C. Between +125 ° C and
+150 ° C, damage does not occur, but the
performance of the amplifier begins to degrade.
The thermal characteristics of the device are dictated
by the package and the PCB. Maximum power
dissipation for a given package can be calculated
using the following formula.
Where:
• P
DMax
is the maximum power dissipation in the
amplifier (W)
• T
Max
is the absolute maximum junction
temperature ( ° C)
Figure 64. Maximum Power Dissipation
• T
A
is the ambient temperature ( ° C)
vs Ambient Temperature
• θ
JA
= θ
JC
+ θ
CA
• θ
JC
is the thermal coefficient from the silicon
When determining whether or not the device satisfies
junctions to the case ( ° C/W)
the maximum power dissipation requirement, it is
• θ
CA
is the thermal coefficient from the case to the
important to not only consider quiescent power
ambient air ( ° C/W)
dissipation, but also dynamic power dissipation. Often
times, this is difficult to quantify because the signal
pattern is inconsistent, but an estimate of the RMS
power dissipation can provide visibility into a possible
problem.
Copyright © 2003 – 2009, Texas Instruments Incorporated Submit Documentation Feedback 21
Product Folder Link(s): THS3201