Thermal considerations, Continued), Surface mount information – GE Industrial Solutions EHW007A0B Series (Eighth-Brick) User Manual

Page 10: Pick and place, Nozzle recommendations, Tin lead soldering

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Data Sheet

October 2, 2009

EHW007A0B Series Eighth-Brick Power Modules

36–75Vdc Input; 12.0Vdc Output; 7A Output Current

LINEAGE

POWER

10

Thermal Considerations

(continued)

O

U

TP

UT

CU

RRE

NT

, I

O

(A

)

3

4

5

6

7

8

20

30

40

50

60

70

80

90

0.5 m/s

(100 LFM)

NC

AMBIENT TEMEPERATURE, T

A

(

o

C

)

Figure 18. Output Current Derating for the Module
with Heatplate and 1.0 in. heat sink; Airflow in the
Transverse Direction from Vout(+) to Vout(-); Vin
=48V.

Surface Mount Information

Pick and Place

The EHW007A0B modules use an open frame
construction and are designed for a fully automated
assembly process. The modules are fitted with a
label designed to provide a large surface area for pick
and place operations. The label meets all the
requirements for surface mount processing, as well as
safety standards, and is able to withstand reflow
temperatures of up to 300

o

C. The label also carries

product information such as product code, serial
number and the location of manufacture.

Figure 17. Pick and Place Location.

Nozzle Recommendations

The module weight has been kept to a minimum by
using open frame construction. Even so, these
modules have a relatively large mass when compared
to conventional SMT components. Variables such as
nozzle size, tip style, vacuum pressure and placement
speed should be considered to optimize this process.
The minimum recommended nozzle diameter for
reliable operation is 6mm. The maximum nozzle outer
diameter, which will safely fit within the allowable
component spacing, is 9 mm.
Oblong or oval nozzles up to 11 x 9 mm may also be
used within the space available.

Tin Lead Soldering

The EHW007A0B 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.

RE

F

LO

W

T

E

MP

(

°C)

0

50

100

150

200

250

300

Preheat zo ne
max 4

o

Cs

-1

So ak zo ne
30-240s

Heat zo ne
max 4

o

Cs

-1

Peak Temp 235

o

C

Coo ling
zone
1-4

o

Cs

-1

T

lim

above

205

o

C

REFLOW TIME (S)

Figure 18. Reflow Profile for Tin/Lead (Sn/Pb)
process

MAX

TE

MP S

O

LD

ER

(

°C)

200

205

210

215

220

225

230

235

240

0

10

20

30

40

50

60

Figure 19. Time Limit Curve Above 205

o

C for

Tin/Lead (Sn/Pb) process

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