THS3201-EP_14 Datasheet, PDF (23/34 Pages) Texas Instruments – 1.8-GHz LOW-DISTORTION CURRENT-FEEDBACK AMPLIFIER

THS3201-EP
www.ti.com ..................................................................................................................................................... SGLS283B – APRIL 2005 – REVISED JANUARY 2009
being pulled away from the thermal-pad area
during the reflow process.
7. Apply solder paste to the exposed thermal-pad
area and all of the IC terminals.
8. With these preparatory steps in place, the IC is
simply placed in position and run through the
solder reflow operation as any standard
surface-mount component. This results in a part
that is properly installed.
Power Dissipation and Thermal
Considerations
To maintain maximum output capabilities, the
THS3201 does not incorporate automatic thermal
shutoff protection. The designer must take care to
ensure that the design does not violate the absolute
maximum junction temperature of the device. Failure
may result if the absolute maximum junction
temperature of 150°C is exceeded. For the 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 PC board. Maximum power
dissipation for a given package can be calculated
using the following formula.
P _Dmax
+
T_max *
q
T_A
JA
where:
P_Dmax is the maximum power dissipation in the
amplifier (W).
T_max is the absolute maximum junction
temperature (°C).
T_A is the ambient temperature (°C).
θ_JA = θ_JC + θ_CA
θ_JC is the thermal coefficient from the silicon
junctions to the case (°C/W).
θ_CA is the thermal coefficient from the case to
ambient air (°C/W).
For systems where heat dissipation is more critical,
the THS3201 is offered in an 8-pin MSOP with
PowerPAD and the THS3201 is available in the
SOIC-8 PowerPAD package offering even better
thermal performance. The thermal coefficient for the
PowerPAD packages are substantially improved over
the traditional SOIC. Maximum power dissipation
levels are listed in the Dissipation Ratings table.. The
data for the PowerPAD packages assume a board
layout that follows the PowerPAD layout guidelines
referenced above and detailed in the PowerPAD
application report SLMA002. Figure 65 also shows
the effect of not soldering the PowerPAD to a PCB.
The thermal impedance increases substantially,
which may cause serious heat and performance
issues. Be sure to always solder the PowerPAD to
the PCB for optimum performance.
4.0
T_J = 125°C
3.5
3.0
θ_JA = 58.4°C/W
2.5
θ_JA = 98°C/W
2.0
1.5
1.0
0.5
θ_JA = 158°C/W
0.0
-40 -20 0 20 40 60 80 100
T_A - Free-Air Temperature - °C
Results are With No Air Flow and PCB Size = 3”x3”
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
Figure 65. Maximum Power Dissipation vs
Ambient Temperature
When determining whether or not the device satisfies
the maximum power-dissipation requirement, it is
important to not only consider quiescent power
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.
Design Tools
Evaluation Fixture, Spice Models, and
Applications Support
TI is committed to providing its customers with the
highest quality of applications support. To support this
goal, an evaluation board has been developed for the
THS3201 operational amplifier. The board is easy to
use, allowing for straightforward evaluation of the
device. The evaluation board can be ordered through
the TI web site, www.ti.com, or through your local TI
sales representative. The schematic diagram, board
layers, and bill of materials of the evaluation boards
are in Figure 66 through Figure 70.
Copyright © 2005–2009, Texas Instruments Incorporated
Product Folder Link(s): THS3201-EP
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