0437008.WR.

**Surface Mount Fuses** 

Ceramic Fuse > 437 Series 

## 437 Series – 1206 Fast-Acting Fuse 

## ~~**RoHS Pb** |_ JQHF cSAkis @.~~ 

## ~~**Description** Po~~ 

This 100% Lead-free, RoHS compliant and Halogen-free fuse series has been designed specifically to provide over current protection to circuits might encounter high working ambient temperatures (up to 150ºC). 

The general design ensures excellent temperature stability and performance reliability. 

In addition to this, the high I²t values typical of the Littelfuse Ceramic Fuse family ensure high inrush current withstand capability. 

## ~~**Features** Po~~ 

- Operating Temperature • Suitable for both leaded from -55ºC to +150ºC and lead-free reflow / wave soldering 

- • 100% Lead-free, HalogenFree and RoHS compliant • UL Recognized to UL/ CSA/NMX 248-1 and UL/ CSA/NMX 248-14 

## ~~**Agency Approvals** Lo~~ 

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|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|Agency|Agency File Number|Ampere Range|
|CSA/NMX 248-1 and UL/|
|E10480|0.250A - 8A|
|cWAd|us|CSA/NMX 248-14|
|29862|0.250A - 8A|
|Applications|
|g,|Po|
|• LCD Displays|• Scanners|
|• Servers|• Data Modems|
|• Printers|
|Electrical Characteristics for Series|
|Lo|
|% of Ampere Rating|Ampere Rating|Opening Time at 25ºC|Additional Information|
|100%|250mA - 8A|4 hours, Minimum|
|250%|750mA - 8A|5 seconds, Maximum|
|350%|250mA -500mA|5 seconds, Maximum|
|350%|750mA - 8A|1 second, Maximum|
|a|Datasheet|Resources|Samples|a|
|Electrical Specifcations by Item|
|Lo|
|Ampere|Max.|Nominal|Nominal|Nominal Voltage|Nominal Power|||Agency Approvals|
|Rating|CodeAmp|Voltage|Interrupting Rating|[1]|Resistance|Melting I|[2]|t|Drop At Rated|Dissipation At Rated|
|(A)|Rating (V)|(Ohms)|[2]|(A|[2]|Sec.)|[3]|Current (V)|[4]|Current (W)|
|0.25|.250|125|2.29|0.003|0.78|0.195|x|x|
|50 A @ 125 V AC/DC|
|0.375|.375|125|a|1.33|0.01|0.6|0.225|||x|x|
|0.5|.500|63|0.908|0.018|0.52|0.26|x|x|
|0.75|.750|63|——|0.665|0.064|0.45|0.338|||x|x|
|1.0|001.|63|0.42|0.1|0.41|0.41|x|x|
|1.25|1.25|63|50 A @ 63 V AC/DC|——|0.318|0.256|0.4|0.5|||x|x|
|1.5|01.5|63|0.209|0.324|0.39|0.585|x|x|
|1.75|1.75|63|——|0.071|0.075|0.27|0.473|||x|x|
|2.0|002.|63|0.058|0.225|0.2|0.4|x|x|
|2.5|02.5|45|——|0.043|0.441|0.15|0.375|||x|x|
|3.0|003.|45|0.033|0.506|0.14|0.42|x|x|
|3.5|03.5|45|50A @ 45V AC/63V DC|a|0.027|0.777|0.13|0.455|||x|x|
|4.0|004.|45|0.022|1.024|0.13|0.52|x|x|
|5.0|005.|45|0.0159|2.3|0.13|0.65|x|x|
|7.0|007.|32|0.01|5.02|0.13|0.91|x|x|
|50 A @ 32 V AC/35 V DC|
|8.0|a|008.|32|———|0.008|7.23|0.13|1.04|||x|x|
|——|||

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**Notes:** 

**1.** AC Interrupting Rating tested at rated voltage with unity power factor. DC Interrupting Rating tested at rated voltage with time constant < 0.8 msec. 

**2.** Nominal Resistance measured with < 10% rated current. 

**3.** Contact Littelfuse if application transient surges are less than 1 ms. 

**4.** Nominal Voltage Drop measured at rated current after temperature has stabilized. 

- Devices designed to carry rated current for 4 hours minimum. It is recommended that devices be operated continuously at no more than 80% rated current. See “Temperature Re-rating Curve”for additional re-rating information. Devices designed to be mounted with marking code facing up. 

© 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/19/20 

**Surface Mount Fuses** Ceramic Fuse > 437 Series 

## ~~**Temperature Re-rating Curve**~~ 

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140<br>120<br>100<br>80<br>60<br>40<br>-65     -45      -25       -5        15       35       55       75       95      115     135    155<br>TEMPERATURE (°C)<br>PERCENT OF RATING<br>**----- End of picture text -----**<br>


## **Note:** 

**1.** Re-rating depicted in this curve is in addition to the standard re-rating of 20% for continuous operation. **Example:** 

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For continuous operation at 75 degrees celsius, the fuse should be rerated as follows:<br>I = (0.80)(0.85)IRAT = (0.68)IRAT<br>Soldering Parameters<br>Reflow Condition Pb – free assembly<br>- Temperature Min (Ts(min)) 150°C<br>Pre Heat - Temperature Max (Ts(max)) 200°C<br>- Time (Min to Max) (ts) 60 – 180 seconds<br>Average Ramp-up Rate (Liquidus Temp (TL) to peak) 3°C/second max.<br>TS(max) to TL - Ramp-up Rate 5°C/second max.<br>Reflow - Temperature (TL) (Liquidus) 217°C<br>- Temperature (tL) 60 – 150 seconds<br>Peak Temperature (TP) 260 [+0/-5]  °C<br>Time within 5°C of actual peak Temperature (tp) 10 – 30 seconds<br>Ramp-down Rate 6°C/second max.<br>Time 25°C to peak Temperature (TP) 8 minutes max.<br>Do not exceed 260°C<br>=<br>Wave Soldering 260°C, 10 seconds max.<br>**----- End of picture text -----**<br>


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Average Time Current Curves<br>**----- End of picture text -----**<br>


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10<br>1<br>0.1<br>0.01<br>0.001<br>0.1 1 10 100<br>CURRENT IN AMPERES<br>.250A .375A .500A .750A 1A 1.25A  1.5A 1.75A 2A 2.5A 3A3.5A 4A 5A 7A 8A<br>TIME IN SECONDS<br>**----- End of picture text -----**<br>


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t P<br>T P<br>Critical Zone<br>Ramp-up TL to TP<br>T S(max) T L t L<br>Ramp-down<br>Preheat<br>T S(min)<br>t S<br>25<br>time to peak temperature Time<br>(t 25ºC to peak)<br>Temperature<br>**----- End of picture text -----**<br>


© 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/19/20 

**Surface Mount Fuses** 

Ceramic Fuse > 437 Series 

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## ~~**Product Characteristics**~~ 

|**Materials**|**Body:**Advanced Ceramic<br>**Terminations:**Ag / Ni / Sn (100% Lead-free)<br>**Element Cover Coating:**Ceramic/Lead-free Glass|
|---|---|
|**Moisture Sensitivity**<br>**Level**|IPC/JEDEC J-STD-020, Level 1|
|**Solderability**|IPC/EIC/JEDEC J-STD-002, Condition B|
|**Humidity Test**|MIL-STD-202, Method 103, Condition D|
|**Resistance to Solder**<br>**Heat**|MIL-STD-202, Method 210, Condition B|
|**Moisture Resistance**|MIL-STD-202, Method 106|



|**Thermal Shock**|MIL-STD-202, Method 107, Condition B|
|---|---|
|**Mechanical Shock**|MIL-STD-202, Method 213, Condition A|
|**Vibration**|MIL-STD-202, Method 201|
|**Vibration, High Frequency**|MIL-STD-202, Method 204, Condition D|
|**Dissolution of Metallization**|IPC/EIC/JEDEC J-STD-002, Condition D|
|**Terminal Strength**|IEC 60127-4|



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Dimensions<br>3.200 ± 0.1778<br>[0.126 ± 0.007]<br>1.63 +0.10 / -0.2<br>[0.064 +0.004 / -0.008]<br>N<br>3.200 ± 0.1778<br>[0.126 ± 0.007]<br>1.000<br>[0.039]<br>1.63 +0.10 / -0.2<br>[0.064 +0.004 / -0.008]<br>H<br>0.835 ± 0.15<br>[0.0329 ± 0.006]<br>0.520 ± 0.200<br>[0.020 ± 0.008]<br>1.000 1.500<br>[0.039] [0.059]<br>1.800<br>[0.071]<br>**----- End of picture text -----**<br>


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Part Marking System<br>Amp Code Marking Code Amp Code Marking Code<br>0.25 D 2.0 N<br>0.375 E 2.5 O<br>0.5 F 3.0 P<br>0.75 G 3.5 R<br>1.0 H 4.0 S<br>1.25 J 5.0 T<br>1.5 K 7.0 W<br>1.75 L 8.0 X<br>**----- End of picture text -----**<br>


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Part Numbering System<br>**----- End of picture text -----**<br>


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0437    008.   W    R<br>Series<br>Packaging Code<br>AMP Code R = Reel Pack<br>Quantity Code<br>W = 3000 pcs<br>Packaging<br>Packaging Option SpPackaging ecification Quantity [Quantity & Packaging ] Code<br>8mm Tape  EIA-481, IEC 60286-3 3000 WR<br>& Reel<br>**----- End of picture text -----**<br>


**Disclaimer Notice -** Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation.  Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation.  Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation.  The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and test each product selected for their own applications.  Littelfuse products are not designed for, and may not be used in, all applications. Read complete Disclaimer Notice at www.littelfuse.com/disclaimer-electronics. 

© 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/19/20