MF-MSMF Series – PTC Resettable Fuses

Specifications are subject to change without notice.

Users should verify actual device performance in their specific applications.

The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

Solder Reflow Recommendations

Temperature of Lead/Pad Junction

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1. Apply solder paste to

• Sn 96.5 / Ag 3.0 / Cu 0.5

Room temperature

test board (8 - 10 mil thick)

Alloy water soluble or no

clean solder paste

(see note 1)

• single sided epoxy glass

(G10) (UL approved)

• PC board approx. 4x4x.06 in.

2. Place test units onto board

6 units/board

3. Ramp up

Convection oven

(see note 2)

2.5 °C ± 0.5 °/sec.

4. Preheat (TS

.

c

e

s

0

3

±

0

9

C

°

0

9

1

o

t

C

°

0

5

1

)

5. Time above liquidus (TL

.

c

e

s

0

9

-

0

6

C

°

0

2

2

)

6. Peak temperature (TP

°

5

-

/

°

0

+

C

°

0

5

2

)

10-20 sec. within

5 °C of peak

.

c

e

s

/

C

°

5

.

0

±

C

°

3

e

r

u

t

a

r

e

p

m

e

t

m

o

o

R

n

w

o

d

p

m

a

R

.

7

(see note 2)

8. Cleaning water clean profile High pressure deionized

72 °F to 160 °F

As required

water 65 PSI max.

(22 °C to 71 °C)

Inspect solder joint to determine if solder joint is

acceptable (i.e. exhibits wetting of joint’s surface).

Use the following criteria (ref. acceptability of printed

board assemblies, IPC-A-610):

A) Acceptable (see Figure 1)

(1) The solder connection wetting angle (solder to

component and solder to PCB termination)

does not exceed 90 °.

(2) Solder balls that do not violate minimum

electrical clearances and are attached

(soldered) to a metal surface.

B) Unacceptable (see Figure 2)

(1) Solder connection wetting angle exceeding

90 °.

(2) Incomplete reflow of solder paste.

(3) Dewetting.

If unacceptable, determine cause and correct prior to

next run.

NOTES:

1. Water soluble solder paste only above 100K.

2. Refer to ref. temperature profile. Temperature at

lead/pad junction with “K” type thermocouple.

3. Units that are board mounted for environmental

testing must see a peak temperature in the reflow

zone, as specified. This is to ensure that all test

units will see “worst case conditions”.

4. Ramp down rate to be measured from 245 °C to

150 °C.

5. Process Description 8 does not apply to open

frame trimmers.

(Derived using 6-zone Convection Oven)

TP

TP

tp

ts

TTO

RAMP-UP

L

TL

t L

T MAX.

S

T MIN.

25

PREHEAT

S

Time

CRITICAL ZONE

RAMP-DOWN

t 25 °C TO PEAK

Notes:

• MF-MSMF models are intended for reflow soldering

(including but not limited to heating plate, hot air, IR,

nitrogen, and vapor phase).

• Wave soldering is permissible only if the device is on the top

of the PCB, opposite the heat source.

• Hand soldering is not recommended for these devices.

• All temperatures refer to the topside of the device,

measured on the device body surface.

• If reflow temperatures exceed the recommended profile,

devices may not meet the published specifications.

• Compatible with Pb and Pb-free solder reflow profiles.

• Excess solder may cause a short circuit.

• Please refer to the Multifuse® Polymer PTC Resettable Fuse

Soldering Recommendations document for more details.

Profile Feature

Pb-Free Assembly

Average Ramp-Up Rate (Tsmax to Tp)

3 °C / second max.

PREHEAT:

Temperature Min. (Tsmin)

Temperature Max. (Tsmax)

Time (Tsmin to Tsmax) (ts)

150 °C

200 °C

60~180 seconds

TIME MAINTAINED ABOVE:

Temperature (TL)

Time (tL)

217 °C

60~150 seconds

Peak Temperature (Tp)

260 °C

Time within 5 °C of Actual Peak Temperature (tp)

20~40 seconds

Ramp-Down Rate

6 °C / second max.

Time 25 °C to Peak Temperature

8 minutes max.

Packaging Dimensions – continued (see next page for dimensions)

B1

N(HUB DIA.)

(MEASURED

AT HUB)

A

T

COVER

TAPE

K0

T1

A0

W2

(MEASURED

AT HUB)

W1

P1

B0

F

D0

P2

P0

E2

E1

W