hsdl-3202 ETC-unknow, hsdl-3202 Datasheet - Page 12

• Manufacturer Part Number: hsdl-3202
• Description: Irda Data Power Compliant 115.2 Kb/s Infrared Transceiver
• Manufacturer: ETC-unknow

Reflow Profile
The reflow profile is a straight
line representation of a nominal
temperature profile for a convec-
tive reflow solder process. The
temperature profile is divided
into four process zones, each
with different T/ time tempera-
ture change rates. The T/ time
rates are detailed in the above
table. The temperatures are
measured at the component to
printed-circuit board
connections.
In process zone P1, the PC
board and HSDL-3202
castellation I/O pins are heated to
a temperature of 125 C to acti-
vate the flux in the solder paste.
The temperature ramp-up rate,
R1, is limited to 4 C per second
to allow for even heating of both
the PC board and HSDL-3202
castellation I/O pins.
12
Process Zone
Heat Up
Solder Paste Dry P2, R2
Solder Reflow
Cool Down
230
200
183
170
150
125
100
50
25
0
HEAT
R1
UP
P1
Symbol
P1, R1
P3, R3
P3, R4
P4, R5
50
SOLDER PASTE DRY
R2
P2
100
25 C to 125 C
125 C to 170 C
170 C to 230 C (245 C max.) 4 C/s
230 C to 170 C
170 C to 25 C
T
t-TIME (SECONDS)
150
Process zone P2 should be of
sufficient time duration (> 60
seconds) to dry the solder paste.
The temperature is raised to a
level just below the liquidus point
of the solder, usually 170 C
(338 F).
Process zone P3 is the solder
reflow zone. In zone P3, the tem-
perature is quickly raised above
the liquidus point of solder to
230 C (446 F) for optimum re-
sults. The dwell time above the
liquidus point of solder should be
between 15 and 90 seconds. It
usually takes about 15 seconds to
assure proper coalescing of the
solder balls into liquid solder and
the formation of good solder
connections. Beyond a dwell time
of 90 seconds, the intermetallic
growth within the solder connec-
tions becomes excessive, result-
R3
MAX. 245°C
REFLOW
SOLDER
90 sec.
ABOVE
183°C
MAX.
P3
200
R4
DOWN
COOL
P4
R5
Maximum T/ time
4 C/s
0.5 C/s
–4 C/s
–3 C/s
250
300
ing in the formation of weak and
unreliable connections. The tem-
perature is then rapidly reduced
to a point below the solidus
temperature of the solder, usually
170 C (338 F), to allow the
solder within the connections to
freeze solid.
Process zone P4 is the cool
down after solder freeze. The
cool down rate, R5, from the
liquidus point of the solder to
25 C (77 F) should not exceed
–3 C per second maximum. This
limitation is necessary to allow
the PC board and HSDL-3202
castellation I/O pins to change
dimensions evenly, putting mini-
mal stresses on the HSDL-3202
transceiver.