BC352239A Datasheet, PDF (110/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Solder Profiles
12 Solder Profiles
The soldering profile depends on various parameters necessitating a set up for each application. The data here is
given only for guidance on solder re-flow. There are four zones:
1. Preheat Zone - This zone raises the temperature at a controlled rate, typically 1-2.5°C/s.
2. Equilibrium Zone - This zone brings the board to a uniform temperature and also activates the flux.
The duration in this zone (typically 2-3 minutes) will need to be adjusted to optimise the out gassing of
the flux.
3. Reflow Zone - The peak temperature should be high enough to achieve good wetting but not so high as
to cause component discoloration or damage. Excessive soldering time can lead to intermetallic growth
which can result in a brittle joint.
4. Cooling Zone - The cooling rate should be fast, to keep the solder grains small which will give a longer
lasting joint. Typical rates will be 2-5°C/s.
12.1 Solder Re-flow Profile for Devices with Lead-Free Solder Balls
Composition of the solder ball: Sn 95.5%, Ag 4.0%, Cu 0.5%
Lead Free Reflow Solder Profile 2
300
250
200
150
100
50
0
0
50
100
150
200
250
300
350
400
450
500
Time (s)
Figure 13.12.1: Typical Lead-Free Re-flow Solder Profile
Key features of the profile:
! Initial Ramp = 1-2.5°C/sec to 175°C±25°C equilibrium
! Equilibrium time = 60 to 180 seconds
! Ramp to Maximum temperature (250°C) = 3°C/sec max.
! Time above liquidus temperature (217°C): 45-90 seconds
! Device absolute maximum reflow temperature: 260°C
Devices will withstand the specified profile. Lead-free devices will withstand up to 5 reflows to a maximum
temperature of 260°C.
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
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