THS4021_16 Datasheet, PDF (16/29 Pages) Texas Instruments – 350-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS

THS4021
THS4022
SLOS265C – SEPTEMBER 1999 – REVISED JULY 2007
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7. Apply solder paste to the exposed thermal pad area and all of the IC terminals.
8. With these preparatory steps in place, the THS402xDGN 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.
The actual thermal performance achieved with the THS402xDGN in its PowerPAD package depends on the
application. In the example above, if the size of the internal ground plane is approximately 3 inches × 3 inches
(7.62 cm × 7.62 cm), then the expected thermal coefficient, θ_JA, is about 58.4°C/W. For comparison, the
non-PowerPAD version of the THS402x IC (SOIC) is shown. For a given θ_JA, the maximum power dissipation is
shown in Figure 39 and is calculated by the following formula:
ǒ Ǔ PD +
TMAX–TA
q_JA
where:
P_D = Maximum power dissipation of THS402x IC (watts)
T_MAX = Absolute maximum junction temperature (150°C)
T_A = Free-ambient air temperature (°C)
θ_JA = θ_JC + θ_CA
θ_JC = Thermal coefficient from junction to case
θ_CA = Thermal coefficient from case to ambient air (°C/W)
MAXIMUM POWER DISSIPATION
vs
FREE-AIR TEMPERATURE
3.5
DGN Package
θ_JA = 58.4°C/W
T_J = 150°C
3.0
2 oz. Trace And Copper Pad
With Solder
2.5
SOIC Package
High-K Test PCB
2.0 θ_JA = 98°C/W
DGN Package
θ_JA = 158°C/W
2 oz. Trace And
Copper Pad
Without Solder
1.5
1.0
0.5 ^{SOIC Package}
Low-K Test PCB
θ_JA = 167°C/W
0.0
−40 −20 0 20 40 60 80 100
T_A − Free-Air Temperature − °C
G029
NOTE: Results are with no air flow and PCB size = 3 in. × 3 in. (7.62 cm × 7.62 cm).
Figure 39. Maximum Power Dissipation vs Free-Air Temperature
More-complete details of the thermal pad installation process and thermal management techniques can be found
in the PowerPAD Thermally Enhanced Package application report (SLMA002).
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