Product Overview
Raychem SMD250 PolySwitch Resettable PPTC Fuse - 2.5 A Hold, 15 V DC
Condition
New old stock, unused surplus. The photos show a representative unit from our stock. Same or next business day shipping from our Idaho warehouse. Honest pricing, no nonsense. Online since 1999. We are here for our customers, with a no-hassle satisfaction guarantee.
Product Overview
This is a surface mount PolySwitch resettable fuse: a polymer element that runs low-resistance at normal current, goes high-resistance when an overcurrent or high ambient heats it past its transition point, and resets itself once power is removed and it cools. The PolySwitch line began at Raychem, passed to Tyco Electronics, and is published today by Littelfuse. Our stock sits in cut black carrier tape with a clear cover, and the bodies photographed here are gold-colored, marked with the crossed PolySwitch logo followed by 250 on the first line and KZ9F on the second.
Key Features
- Hold current IH: 2.50 A at 25 degC, per Littelfuse's published SMD series data
- Trip current IT: 5.00 A at 25 degC, per Littelfuse's published SMD series data
- Maximum voltage VMAX: 15 V DC
- Maximum fault current IMAX: 40 A
- Resistance: 0.035 ohm minimum initial, 0.085 ohm maximum post-trip
- Operating range: -40 degC to +85 degC
- Body marking on the photographed units: crossed PolySwitch logo, 250, lot code KZ9F
- Package: surface mount chip; the case size is not marked on the part. Littelfuse builds SMD250 in both the 2920 and 3425 cases, and the 1.9 W dissipation figure applies to the 3425
- Verify against Littelfuse's published PolySwitch SMD series data before designing in.
Applications
- Overcurrent protection on 5 V and 12 V rails in board-level power supplies
- USB and peripheral port protection where a blown fuse would mean a service call
- Motor, solenoid and small-load branch protection on control boards
- Repair and drop-in replacement of a tripped or missing SMD250 on existing hardware
Frequently Asked Questions
How many should I order? Order the count your build needs. We have 9 on the shelf here and they sell each, cut from tape rather than supplied on a full reel, so a job needing a dozen will outrun this listing. Shipping is $8 flat rate and free on orders over $28, so small parts like this ship smartest as part of a larger order.
Which SMD250 case size is this, 2920 or 3425? We cannot confirm it from the part. Littelfuse builds SMD250 in both cases, and neither the marking on these bodies nor the tape tells you which. The 1.9 W dissipation and 25 second time-to-trip belong to the 3425 case; the only figures established for the unit in your hand are the package-neutral ones above. If footprint matters, measure before you commit: 3425 runs about 8.0 to 9.4 mm long, 2920 about 6.7 to 8.0 mm.
A fuse you never have to replace is a strange thing to keep nine of, which is exactly why the ones that do get used are usually the ones nobody stocked.
