briefly elevates the temperature
sufficiently to produce a reflow
of the solder.
The recommended lead-free
reflow profile is shown in Fig-
ure 22.
Electronic devices may be
subjected to ESD damage in any
of the following areas:
• Storage & handling
• Inspection
• Assembly & testing
• In-circuit use
The rates of change of tempera-
ture for the ramp-up and cool-
down zones are chosen to be low
enough to not cause deformation
of board or damage to compo-
nents due to thermal shock. The
maximum temperature in the
reflow zone (Tmax) should not
exceed 235°C for leaded solder.
Electrostatic Sensitivity
FETs and RFICs are electrostatic
discharge (ESD) sensitive de-
vices. Agilent devices are manu-
factured using a very robust and
The ATF-541M4 is an ESD Class 1
reliable PHEMT process, however, device. Therefore, proper ESD
precautions are recommended
when handling, inspecting,
jected to high-energy electrostatic testing, and assembling these
permanent damage may occur to
these devices if they are sub-
discharges. Electrostatic charges
as high as several thousand volts
(which readily accumulate on the Any user-accessible points in
devices to avoid damage.
These parameters are typical for
a surface mount assembly
process for the ATF-541M4. As a
general guideline, the circuit
board and components should
only be exposed to the minimum
temperatures and times the
necessary to achieve a uniform
reflow of solder.
human body and on test equip-
ment) can discharge without
detection and may result in
failure or degradation in perfor-
mance and reliability.
wireless equipment (e.g. antenna
or battery terminals) provide an
opportunity for ESD damage.
For circuit applications in which
the ATF-541M4 is used as an
input or output stage with close
coupling to an external antenna,
the device should be protected
from high voltage spikes due to
human contact with the antenna.
A good practice, illustrated in
Figure 23, is to place a shunt
inductor or RF choke at the
antenna connection to protect
the receiver and transmitter
circuits. It is often advantageous
to integrate the RF choke into the
design of the diplexer or T/R
switch control circuitry.
250
200
TMAX
150
Reflow
Zone
100
Preheat
Zone
Cool Down
Zone
50
0
0
60
120
180
240
300
TIME (seconds)
Figure 21. Leaded Solder Reflow Profile.
350
300
Peak Temperature
Min. 240°C
Max. 255°C
250
221
Figure 23. In-circuit ESD Protection.
Reflow Time
Min. 60s
Max. 90s
200
150
100
Preheat 130–170°C
Min. 60s
Max. 150s
50
0
0
30
60
90
120 150
180 210
240
270
300
330 360
TIME (seconds)
Figure 22. Lead-free Solder Reflow Profile.
11
HP [ HEWLETT-PACKARD ]
