Is there a pin-compatible replacement for 0603L004YR?

While several parts share the 0603 package, no candidates match the critical 40mA hold current. Therefore, no pin-for-pin functional equivalent has been confirmed.

What risks should I check before replacing 0603L004YR?

The main risk is the hold current (Ihold). Using a part with a higher hold current will reduce protection and could lead to downstream component damage in an overcurrent event. Always verify the new trip characteristics are safe for your application.

0603L004YR Alternatives, Datasheet & Cross Reference | Littelfuse

Reviewing alternatives for the Littelfuse 0603L004YR, a 40mA/24V resettable PTC fuse. Key challenges include finding a match for the low hold current in the same 0603 package.

AI replacement insight

Electrical riskhigh

Using a part with a higher hold current (e.g., 100mA vs 40mA) will not provide the same level of overcurrent protection.

Package risklow

The 0603 package is standard, and candidates with matching footprints are available.

Can it be replaced directly?

No direct pin-to-pin replacement was found. Available alternatives have significantly higher hold currents, requiring careful circuit analysis.

Best replacement path

Search for PTC fuses in a 0603 package with a hold current between 40mA and 60mA and a voltage rating of 24V or higher.

Main risk

The primary risk is using a replacement with a higher hold current, which will not protect the circuit at the intended 40mA level.

Recommended alternatives

A functional alternative in a 0603 package with higher voltage rating, but a 100mA hold current that requires engineering review.

View details

Alternative comparison matrix

Feature / factor	0603L004YR	SMD0603-010C-33V	SMD0603-020-24V	Compatibility / risk
Package	0603	0603	0603	0603 — Package size matches.; SMD0603-020-24V: Package size matches.
Voltage	24.0V	33.0V	24.0V	33.0V / 24.0V — Higher voltage rating provides more margin.; SMD0603-020-24V: Maximum voltage rating matches.
Current	0.04A	0.1A	0.2A	0.1A / 0.2A — Hold current is 2.5x higher, altering protection level.; SMD0603-020-24V: Hold current is 5x higher, altering protection level.
Lifecycle	-	Active	-	Active — Candidate is listed as Active.
Power	0.5W	-	0.5W	0.5W — Power dissipation matches.

Application & sourcing insights

Questions & answers

No direct drop-in was found. Candidates like BNstar's SMD0603-010C-33V are functionally similar but have a higher 100mA hold current, which requires design validation.