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0437.250WR

Public Made by Adom

by adom

Littelfuse Disposable Fuses, 1206. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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0437.250WR

Littelfuse · Disposable Fuses · 1206

0437.250WR from Littelfuse, in a 1206. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 1 passive Fuse terminal 1 (Ag/Ni/Sn end termination); non-polarized, 250mA fast-acting, rated 125 V AC/DC with 50 A interrupting rating.
2 2 passive Fuse terminal 2 (Ag/Ni/Sn end termination); non-polarized, interchangeable with terminal 1, nominal resistance 2.290 ohms.

Key specifications

Parameter Value
Manufacturer Littelfuse
Package 1206
Category Circuit Protection
Pins 2

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Operating temperature -55 150 ºC 1
Opening time, 100% of ampere rating (250mA-8A) 4 hours 100% of rating, 250mA-8A, at 25ºC 1
Opening time, 350% of ampere rating (250mA-500mA) 5 seconds 350% of rating, 250mA-500mA, at 25ºC 1
Max. voltage rating 125 V Amp code .250 (250mA) row 1
Interrupting rating 50 A @ 125 V AC/DC 1
Continuous operation current 80 % rated current Continuous operation, recommended 1
Nominal resistance 2.29 Ohms Measured with <10% rated current 1
Nominal melting I2t 0.003 A2Sec. 1
Nominal voltage drop at rated current 0.78 V At rated current, after temperature has stabilized 1
Nominal power dissipation at rated current 0.195 W At rated current 1
Reflow preheat temperature min (Ts(min)) Ts(min) 150 ºC Pb-free reflow, pre-heat 2
Reflow preheat temperature max (Ts(max)) Ts(max) 200 ºC Pb-free reflow, pre-heat 2
Reflow preheat time (ts) ts 60 180 seconds Pre-heat, Ts(min) to Ts(max) 2
Reflow time above liquidus (tL) tL 60 150 seconds Reflow, Pb-free 2
Peak temperature (TP) TP 260 ºC Pb-free reflow; printed as 260+0/-5 °C 2
Time within 5°C of actual peak temperature (tp) tp 10 30 seconds Within 5°C of actual peak temperature 2
Average ramp-up rate (TL to peak) 3 °C/second Liquidus (TL) to peak 2
TS(max) to TL ramp-up rate 5 °C/second TS(max) to TL 2
Ramp-down rate 6 °C/second Peak to cooldown 2
Time 25°C to peak temperature 8 minutes 25°C to peak temperature (TP) 2
Maximum soldering temperature 260 ºC Pb-free reflow; 'Do not exceed 260°C' 2
Wave soldering temperature 260 ºC Wave soldering 2
Wave soldering time 10 seconds Wave soldering at 260°C 2

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts tin Terminations: Ag / Ni / Sn (100% Lead-free) Element Cover Coating: Ceramic/Lead-free 3

CAD (KiCad official)

  • Symbol: 0437.250WR
  • Footprint: Fuse:Fuse_1206_3216Metric
  • 3D model: 1206 (KiCad packages3D, STEP)
  • 3D model files: 0437-250wr-etched.step / 0437-250wr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); 0437-250wr.step / 0437-250wr.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Littelfuse datasheet (3 pp, sha256 4118dc56d128f864, retrieved 2026-10-17, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text+vision), consensus claude-opus-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF