Datasheet

9
The reow prole is a straight-line representation of a nominal temperature prole for a convective reow solder
process. The temperature prole is divided into four process zones, each with dierent DT/Dtime temperature change
rates or duration. The DT/Dtime rates or duration are detailed in the above table. The temperatures are measured at
the component to printed circuit board connections.
Process zone P1, the PC board and APDS-9005 pins are heated to a temperature of 150°C to activate the ux in the
solder paste. The temperature ramp up rate, R1, is limited to 3°C per second to allow for even heating of both the PC
board and APDS-9005 pins.
Process zone P2 should be of sucient time duration (100 to 180 seconds) to dry the solder paste. The temperature is
raised to a level just below the liquidus point of the solder, usually 200°C (392°F).
Process zone P3 is the solder reow zone. In zone P3, the temperature is quickly raised above the liquidus point of
solder to 255°C (491°F) for optimum results. The dwell time above the liquidus point of solder should be between 20
and 40 seconds. It usually takes about 20 seconds to assure proper coalescing of the solder balls into liquid solder and
the formation of good solder connections. Beyond a dwell time of 40 seconds, the intermetallic growth within the
solder connections becomes excessive, resulting in the formation of weak and unreliable connections. The tempera-
ture is then rapidly reduced to a point below the solidus temperature of the solder, usually 200°C (392°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 6°C per second maximum. This limitation is necessary to allow the PC board and APDS-
9005 pins to change dimensions evenly, putting minimal stresses on the APDS-9005.
It is recommended to perform reow soldering no more than twice.
Recommended Reow Prole
50
100 150 200 250 300
t-TIME
(SECONDS)
25
80
120
150
180
200
230
255
0
T - TEMPERATURE (˚C)
R1
R2
R3
R4
R5
217
MAX 260˚C
60 sec to 90 sec
Above 217˚C
P1
HEAT
UP
P2
SOLDER PASTE DRY
P3
SOLDER
REFLOW
P4
COOL DOWN
Process Zone Symbol DT
Maximum DT/Dtime
or Duration
Heat Up P1, R1 25°C to 150°C 3°C/s
Solder Paste Dry P2, R2 150°C to 200°C 100s to 180s
Solder Reow P3, R3 200°C to 255°C 3°C/s
P3, R4 255°C to 200°C -6°C/s
Cool Down P4, R5 200°C to 25°C -6°C/s
Time maintained above 217°C > 217°C 60s to 90s
Peak Temperature 260°C
Time within 5°C of actual Peak Temperature > 255°C 20s to 40s
Time 25°C to Peak Temperature 25°C to 260°C 8mins