HSMP-3820 Datasheet, PDF (7/10 Pages) AVAGO TECHNOLOGIES LIMITED – Surface Mount RF PIN Switch and Limiter Diodes Tape and Reel Options Available

SMT Assembly
Reliable assembly of surface mount components is a
complex process that involves many material, process,
and equipment factors, including: method of heating
(e.g., IR or vapor phase reflow, wave soldering, etc.) circuit
board material, conductor thickness and pattern, type of
solder alloy, and the thermal conductivity and thermal
mass of components. Components with a low mass, such
as the SOT-323/-23 package, will reach solder reflow
temperatures faster than those with a greater mass.
Avago’s diodes have been qualified to the time-
temperature profile shown in Figure 21. This profile is
representative of an IR reflow type of surface mount
assembly process.
After ramping up from room temperature, the circuit
board with components attached to it (held in place with
solder paste) passes through one or more preheat zones.
The preheat zones increase the temperature of the
board and components to prevent thermal shock and
begin evaporating solvents from the solder paste. The
reflow zone briefly elevates the temperature sufficiently
to produce a reflow of the solder.
The rates of change of temperature for the ramp-up and
cool-down zones are chosen to be low enough to not
cause deformation of the board or damage to components
due to thermal shock. The maximum temperature in the
reflow zone (T_MAX) should not exceed 260°C.
These parameters are typical for a surface mount
assembly process for Avago diodes. As a general
guideline, the circuit board and components should be
exposed only to the minimum temperatures and times
necessary to achieve a uniform reflow of solder.
Tp
T_L
Ts _max
Ramp-up
tp
t_L
Critical Zone
T _L to Tp
Ts _min
ts
Preheat
Ramp-down
25
t 25° C to Peak
Time
Figure 21. Surface Mount Assembly Profile.
Lead-Free Reflow Profile Recommendation (IPC/JEDEC J-STD-020C)
Reflow Parameter
Average ramp-up rate (Liquidus Temperature (T to Peak)
S(max)
Preheat
Temperature Min (T )
S(min)
Temperature Max (T )
S(max)
Time (min to max) (t_S)
Ts(max) to TL Ramp-up Rate
Time maintained above:
Temperature (T )
L
Time (t )
L
Peak Temperature (T )
P
Time within 5 °C of actual Peak temperature (t )
P
Ramp-down Rate
Time 25 °C to Peak Temperature
Lead-Free Assembly
3°C/ second max
150°C
200°C
60-180 seconds
3°C/second max
217°C
60-150 seconds
260 +0/-5°C
20-40 seconds
6°C/second max
8 minutes max
Note 1: All temperatures refer to topside of the package, measured on the package body surface
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