THS6062_16 Datasheet, PDF (25/36 Pages) Texas Instruments – LOW-NOISE ADSL DUAL DIFFERENTIAL RECEIVER

THS6062
www.ti.com
SLOS228D – JANUARY 1999 – REVISED OCTOBER 2007
installed.
The actual thermal performance achieved with the THS6062DGN 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,
then the expected thermal coefficient, θ_JA, is about 58.4°C/W. For comparison, the non-PowerPAD version of the
THS6062 IC (SOIC) is shown. For a given θ_JA, the maximum power dissipation is shown in Figure 49 and is
calculated by the following formula:
ǒ Ǔ PD +
TMAX–TA
q_JA
(5)
Where:
P_D = Maximum power dissipation of THS6062 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
2 oz. Trace And Copper Pad
With Solder
2.5
SOIC Package
High-K Test PCB
2 ^θJA ^{= 98°C/W}
DGN Package
θ_JA = 158°C/W
2 oz. Trace And
Copper Pad
Without Solder
1.5
1
0.5 ^{SOIC Package}
Low-K Test PCB
θ_JA = 167°C/W
0
−40 −20 0 20 40 60 80 100
T_A − Free-Air Temperature − °C
NOTE: Results are with no air flow and PCB size = 3"× 3"
Figure 49. Maximum Power Dissipation vs Free-Air Temperature
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.
The next thing that should be considered is the package constraints. The two sources of heat within an amplifier
are quiescent power and output power. The designer should never forget about the quiescent heat generated
within the device, especially a multi-amplifier device. Because these devices have linear output stages (Class
A-B), most of the heat dissipation is at low output voltages with high output currents. Figure 50 and Figure 51
show this effect, along with the quiescent heat, with an ambient air temperature of 50°C. When using V_CC = 5 V
or ±5 V, there is generally not a heat problem, even with SOIC packages. But, when using V_CC = ±15 V, the
SOIC package is severely limited in the amount of heat it can dissipate. The other key factor when looking at
these graphs is how the devices are mounted on the PCB. The PowerPAD devices are extremely useful for heat
Copyright © 1999–2007, Texas Instruments Incorporated
Product Folder Link(s): THS6062
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