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Littelfuse Inc. 0603L003/36YR-A — Circuit Protection

Littelfuse 0603L003/36YR-A PTC Resettable Fuse, 30mA Hold

MPN0603L003/36YR-A
Active

Littelfuse POLY-FUSE® 0603L series, polymeric PTC resettable fuse, 0603 (1608 Metric) concave package, 30 mA hold current, 36 V max, 1 s trip time, surface mount.

$2.1900Ref. price · indicative, final on quote
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

0603L003/36YR-A specifications
ParameterValue
TypePolymeric
SeriesPOLY-FUSE®, 0603L
MountingSurface Mount
Voltage - max36V
Current - max40 A
Current - trip90 mA
Current - hold (Ih)30 mA
Operating temperature-40°C ~ 85°C
Size (Dimension)0.063\" L x 0.031\" W (1.60mm x 0.80mm)
Approval agencycURus, TUV
PackageTape & Reel (TR) Cut Tape (CT)
Time to trip1 s
Case0603 (1608 Metric), Concave
Thickness0.039\" (1.00mm)
Resistance - initial (Ri)6 Ohms
Resistance - post trip (R1)50 Ohms

Product details

Active production, 30 mA hold — a fit check for 36V rails

The 0603L003/36YR-A: Its 30 mA hold current (Ih) at 36 V max means it passes normal circuit current up to that point without tripping; once the fault current reaches 90 mA (It), the PTC heats and transitions to a high-resistance state in typically 1 second, protecting downstream components.

0603 footprint, concave termination — board-fit note

Initial series resistance is 6 Ohms minimum, rising to 50 Ohms maximum after a trip event — the post-trip resistance adds a voltage drop that keeps the PTC latched until power is cycled, so the circuit sees a clean open-circuit condition during fault.

Approvals and temperature range

Carries cURus and TUV agency approvals — accepted in North American and European equipment without additional component-level review for the safety agency file.

Frequently asked questions

What does the 30 mA hold current mean for my circuit?

The 30 mA hold current (Ih) is the maximum steady-state current the PTC passes without tripping at 25°C. Above that, once the fault current reaches 90 mA (It), the device trips in typically 1 second. At elevated temperatures the hold current derates, so a 30 mA circuit at 85°C may see the PTC trip on normal current — check the derating curve in the datasheet for your ambient.