Nominal

Nominal

Melting I2T

Agency Approvals

Nominal

Max.

Type SMM

Square Ceramic Surface Mount Medium Blow Fuse

3812 Size

RoHS 6 Compliant

Electrical Specifications

SMM Feb 2012C

Pb

20A

0.0025

0.09

25A

0.0019

0.08

30A

0.0013

0.07

Soldering Guidelines

Reflow Conditions Recommended: 240°C, 30 sec. max.

Nominal

Volt-drop

@100% In

(volt)

420

1000

Nominal

Power

Dissipation

(W)

Melting I2T

@ 10 In

(A2 Sec)

Min.

Agency Approvals

Ampere

Rating

(A)

Catalog

Number

SMM 20

270

Nominal

Cold

Resistance

(ohm)

SMM 25

SMM 30

Max.

Voltage

Rating

(V)

Interrupting Rating

250

250

250

20A - 30A / 250V @100A AC

125V @ 150A AC

72V @ 130A DC

65V @ 300A DC

1.8

2.0

2.1

Y

Y

Y

Y

Y

Y

Reflow Conditions Recommended: 240°C, 30 sec. max.

Pb-Free Process Compatibility:

Test Conditions

NOTES:

When soldered to test boards using IR reflow in accordance with JEDEC J-STD-020 (260°C, 40 sec. max.), SMM samples exhibited DCR change

of +10% to -20% from initial values.

Subsequent tests showed all samples complied with the stated electrical characteristics on this data sheet.

NOT Recommended for Wave solder / Direct immersion / Hand Solder

For all SMM data, as well as UL Component investigation, all tests were conducted with fuse samples soldered on a PCB (1.6mm thick) test board with

The maximum temperature recorded in open air was 100

temperatures in end-use application with regard to thermal index of surrounding materials and components.

(Maximum temperature recorded at 80% of rating (24A) for the SMM30 rating was 69

-Minimum fusing point:

The SMM Series fuses are NOT intended to be operated at currents between 100% and 200% of ampere rating. Prolonged operation at currents in this

Caution:

– UL Condition of Acceptability

- the following information is contained in the UL Component Recognition for SMM Fuse Series:

copper traces measuring 0.1 mm nominal thickness (3 oz.clad), 10mm wide and 100 mm overall length.

The SMM Series fuses are NOT intended to be operated at currents between 100% and 200% of ampere rating. Prolonged operation at currents in this

range may result in overheating of the fuse and/or desoldering of the fuse caps from the PCB pad.

100

110

120

130

140

Temperature Derating Curve

Average Time Current Curve

SMM - TIME CURRENT CHARACTERISTIC CURVE

20A

25A

30A

50

60

70

80

90

100

-75-65-55-45-35-25-15 -5 5 15 25 35 45 55 65 75 85 95105115125135145

100

1000

10000

100000

0.1

1

10

CORPORATE OFFICE

FAR EAST OFFICE

EUROPE OFFICE

EUROPE

Bel Fuse Inc.

Bel Fuse Ltd.

Bel Fuse Europe Ltd.

Bel Stewart GmbH

206 Van Vorst Street

8/F Luk Hop Industrial Building Preston Technology Management Centre

Industriestrasse 20

Jersey City, NJ 07302

8 Luk Hop Street

Marsh Lane, Suite F15

61381 Friedrichsdorf

0.01

10

100

1000

CURRENT IN AMPERES

Jersey City, NJ 07302

8 Luk Hop Street

Marsh Lane, Suite F15

61381 Friedrichsdorf

Tel 201-432-0463

San Po Kong

Preston, Lancashire, PR1 8UQ

Germany

Fax 201-432-9542  

Kowloon, Hong Kong

United Kingdom

Tel 49-6172-9552-0

E-Mail: belfuse@belfuse.com

Tel 852-2328-5515

Tel 44-1772-556601

Fax 49-6172-9552-40  

Website: www. belfuse.com

Fax 852-2352-3706  

Fax 44-1772-888366