ATF-521P8 View Datasheet(PDF) - HP => Agilent Technologies
Part Name
Description
MFG CO.
ATF-521P8
HP => Agilent Technologies
'ATF-521P8' PDF : 24 Pages View PDF
mounted on a chassis or metal
casing, and the results are given
below:
ATF Demoboard
PCB 1/8" Chassis
PCB no HeatSink
θb-a
10.4°C/W
32.9°C/W
Table 4. Thermal resistance measurements.
Therefore calculating the tem-
perature of the channel for these
two scenarios gives a good
indication of what type of heat
sinking is needed.
Case 1: Chassis Mounted @ 85°C
Tch = P x (θch-b + θb-a) + Ta
=.9W x (45+10.4)°C/W +85°C
Tch = 135°C
Case 2: No Heatsink @ 85°C
Tch = P x (θch-b + θb-a) + Ta
=.9W x (45+32.9)°C/W + 85°C
Tch = 155°C
In other words, if the board is
mounted to a chassis, the chan-
nel temperature is guaranteed to
be 135°C safely below the 150°C
maximum. But on the other
hand, if no heat sinking is used
and the θb-a is above 27°C/W
(32.9°C/W in this case), then the
power must be derated enough to
lower the temperature below
150°C. This can be better under-
stood with Figure 20 below. Note
power is derated at 13 mW/°C
for the board with no heat sink
and no derating is required for
the chassis mounted board until
an ambient temperature of
100°C.
Pdiss
(W)
0.9W
0
81 100
Mounted on Chassis
(18 mW/°C)
No Heatsink
(13 mW/°C)
150 Tamb (°C)
Figure 20. Derating for ATF- 521P8.
Thus, for reliable operation of
ATF-521P8 and extended MTBF,
it is recommended to use some
form of thermal heatsinking. This
may include any or all of the
following suggestions:
• Maximize vias underneath and
around package;
• Maximize exposed surface
metal;
• Use 1 oz or greater copper clad;
• Minimize board thickness;
• Metal heat sinks or extrusions;
• Fans or forced air;
• Mount PCB to Chassis.
Summary
A high linearity Tx driver
amplifier for WCDMA has been
presented and designed using
Agilent’s ATF-521P8. This
includes RF, DC and good ther-
mal dissipation practices for
reliable lifetime operation. A
summary of the typical perfor-
mance for ATF-521P8 demoboard
at 2140 MHz is as follows:
Demo Board Results at 2140 MHz
Gain
OIP3
ACLR
P1dB
NF
16.5 dB
41.2 dBm
-58 dBc
24.8 dBm
1.55 dB
References
[1] Ward, A. (2001) Agilent
ATF-54143 Low Noise Enhance-
ment Mode Pseudomorphic
HEMT in a Surface Mount
Plastic Package, 2001 [Internet],
Available from:
<http://www.agilent.com/view/rf>
[Accessed 22 August, 2002].
[2] Biasing Circuits and
Considerations for GaAs
MESFET Power Amplifiers, 2001
[Internet], Available from:
<http://www.rf-solutions.com/
pdf/AN-0002_ajp.pdf> [Accessed
22 August, 2002]
20
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