AP502 TriQuint, AP502 Datasheet - Page 4

• Manufacturer Part Number: AP502
• Description: RF Amplifier 2110-2170MHz 30dB Gain
• Manufacturer: TriQuint
• Type: Power Amplifierr

Specifications of AP502

• Operating Frequency: 2110 MHz to 2170 MHz
• Operating Supply Voltage: 12 V
• Supply Current: 840 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Number Of Channels: 1 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WJ Communications, Inc • Phone 1-800-WJ1-4401 • FAX: [phone] • e-mail: [e-mail] • Web site: www.wj.com, www.TriQuint.com
The MTTF of the AP502 can be calculated by first
determining how much power is being dissipated by the
amplifier module. Because the device’s intended application
is to be a power amplifier pre-driver or final stage output
amplifier, the output RF power of the amplifier will help
lower the overall power dissipation.
amplifier can be biased with different quiescent currents, so
the calculation of the MTTF is custom to each application.
The power dissipation of the device can be calculated with
the following equation:
While the maximum recommended case temperature on the
datasheet is listed at 85 ˚C, it is suggested that customers
maintain an MTTF above 1 million hours.
convert to a derating curve for maximum case temperature vs.
power dissipation as shown in the plot below.
P
90
80
70
60
50
diss
4
= V
V
I
{The RF power is converted to Watts}
Maximum Recommended Case Temperature vs. Power Dissipation
cc
cc
AP502
UMTS-band 4W HBT Amplifier Module
= Operating current
cc
= Operating supply voltage = 12V
5
* I
cc
– (Output RF Power – Input RF Power),
6
to maintain 1 million hours MTTF
Power Dissipation (Watts)
7
8
9
In addition, the
10
MTTF Calculation
This would
11
12
To calculate the MTTF for the module, the junction
temperature needs to be determined.
calculated with the module’s power dissipation, the thermal
resistance value, and the case temperature of operation:
From a numerical standpoint, the MTTF can be calculated
using the Arrhenius equation:
A graphical view of the MTTF can be shown in the plot
below.
1.E+07
1.E+06
1.E+05
T
MTTF = A* e
j
= P
130
T
P
R
T
A = Pre-exponential Factor = 6.087 x 10
Ea = Activation Energy = 1.39 eV
k = Boltzmann’s Constant = 8.617 x 10
T
diss
diss
j
case
j
th
= Junction temperature
= Junction Temperature (ºK) = T
= Thermal resistance = 9 ˚C/W
= Power dissipation (calculated from above)
* R
= Case temperature of module’s heat sink
th
140
Specifications and information are subject to change without notice
(Ea/k/Tj)
+ T
MTTF vs. Junction Temperature
case
Junction Temperature (°C)
150
Product Information
160
This can be easily
j
(ºC) + 273
-5
170
Page 4 of 5 July 2008
-11
eV/ ºK
hours
180