Surface mount information (continued), Tin lead soldering, Lead free soldering – GE Industrial Solutions EHW015A0A Series (Eighth-Brick) User Manual

Page 11: Pb-free reflow profile, Msl rating, Storage and handling

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Data Sheet

October 2, 2009

EHW015A0A Series Eighth-Brick Power Modules

36–75Vdc Input; 5.0Vdc Output; 15A Output Current

LINEAGE

POWER

11

Surface Mount Information (continued)

The CP is constructed from a solid copper pin with an
integral solder ball attached, which is composed of
tin/lead (Sn/Pb) solder for non-Z codes, or Sn/Ag/Cu

(SAC) solder for –Z codes. The CP connector design is
able to compensate for large amounts of co-planarity
and still ensure a reliable SMT solder joint. Typically,
the eutectic solder melts at 183

o

C (Sn/Pb solder) or

217-218

o

C (SAC solder), wets the land, and

subsequently wicks the device connection. Sufficient
time must be allowed to fuse the plating on the
connection to ensure a reliable solder joint. There are
several types of SMT reflow technologies currently
used in the industry. These surface mount power
modules can be reliably soldered using natural forced
convection, IR (radiant infrared), or a combination of
convection/IR.

Tin Lead Soldering

The EHW015A0A power modules are lead free
modules and can be soldered either in a lead-free
solder process or in a conventional Tin/Lead (Sn/Pb)
process. It is recommended that the customer review
data sheets in order to customize the solder reflow
profile for each application board assembly. The
following instructions must be observed when soldering
these units. Failure to observe these instructions may
result in the failure of or cause damage to the modules,
and can adversely affect long-term reliability.

In a conventional Tin/Lead (Sn/Pb) solder process peak
reflow temperatures are limited to less than 235

o

C.

Typically, the eutectic solder melts at 183

o

C, wets the

land, and subsequently wicks the device connection.
Sufficient time must be allowed to fuse the plating on
the connection to ensure a reliable solder joint. There
are several types of SMT reflow technologies currently
used in the industry. These surface mount power
modules can be reliably soldered using natural forced
convection, IR (radiant infrared), or a combination of
convection/IR. For reliable soldering the solder reflow
profile should be established by accurately measuring
the modules CP connector temperatures.

R

E

FLO

W

TEMP (

°C)

0

50

100

150

200

250

300

Preheat zo ne
max 4

o

Cs

-1

Soak zo ne
30-240s

Heat zone
max 4

o

Cs

-1

Peak Temp 235

o

C

Co oling
zone
1-4

o

Cs

-1

T

lim

above

205

o

C

REFLOW TIME (S)

Figure 25. Reflow Profile for Tin/Lead (Sn/Pb)
process.

M

A

X T

E

M

P

SO

LD

E

R

(

°C)

200

205

210

215

220

225

230

235

240

0

10

20

30

40

50

60

Figure 26. Time Limit Curve Above 205

o

C for

Tin/Lead (Sn/Pb) process

Lead Free Soldering

The –Z version of the EHW015A0A modules are lead-
free (Pb-free) and RoHS compliant and are both
forward and backward compatible in a Pb-free and a
SnPb soldering process. Failure to observe the
instructions below may result in the failure of or cause
damage to the modules and can adversely affect long-
term reliability.

Pb-free Reflow Profile

Power Systems will comply with J-STD-020 Rev. C
(Moisture/Reflow Sensitivity Classification for
Nonhermetic Solid State Surface Mount Devices) for
both Pb-free solder profiles and MSL classification
procedures. This standard provides a recommended
forced-air-convection reflow profile based on the
volume and thickness of the package (table 4-2). The
suggested Pb-free solder paste is Sn/Ag/Cu (SAC).
The recommended linear reflow profile using Sn/Ag/Cu
solder is shown in Figure 27.

MSL Rating

The EHW015A0A modules have a MSL rating of 2.

Storage and Handling

The recommended storage environment and handling
procedures for moisture-sensitive surface mount
packages is detailed in J-STD-033 Rev. A (Handling,
Packing, Shipping and Use of Moisture/Reflow
Sensitive Surface Mount Devices). Moisture barrier
bags (MBB) with desiccant are required for MSL ratings
of 2 or greater. These sealed packages should not be
broken until time of use. Once the original package is

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