Is there a pin-compatible replacement for 0451004.MRL?

Candidates from the same product family, such as 0451007.MRL, are likely pin-compatible, but this must be verified by comparing datasheets. The primary difference is the electrical rating.

What risks should I check before replacing 0451004.MRL?

The main risk is the current rating. Using a fuse with a higher rating (e.g., 7A instead of 4A) will not protect the circuit as designed and could lead to damage. Also, verify the package dimensions and land pattern are identical.

0451004.MRL Alternatives, Datasheet & Cross Reference | Littelfuse

Reviewing alternatives for the Littelfuse 0451004.MRL, a 4A 125V very fast-acting SMD fuse. Key considerations for substitutes include matching the current rating, voltage rating, and physical package.

AI replacement insight

Electrical riskhigh

Higher current rating fails to protect the circuit at the designed threshold.

Package risklow

Candidates from the same series likely share the same package and land pattern.

Can it be replaced directly?

No direct, drop-in replacement for the 0451004.MRL has been identified. All potential candidates have different current ratings.

Best replacement path

Select a fuse from the same Littelfuse 451 series with the closest possible current rating, but only if the application can tolerate the change.

Main risk

The primary risk is using a substitute with a higher current rating, which compromises the intended over-current protection.

Recommended alternatives

From the same product series (451) but with a higher current rating. Electrical and pinout verification is required.

View details

Alternative comparison matrix

Feature / factor	0451004.MRL	0451007.MRL	045106.3MRL	0453010.MR	Compatibility / risk
Current	4.0A	7.0A	6.3A	10.0A	7.0A / 6.3A / 10.0A — Candidate has a higher current rating, offering less protection.; 045106.3MRL: Candidate has a higher current rating, offering less protection.; 0453010.MR: Candidate current rating is 2.5x higher, offering significantly less protection.
Voltage	125V	125V	125V	125V	125V — Voltage rating matches.; 045106.3MRL: Voltage rating matches.; 0453010.MR: Voltage rating matches.
Package	SMD	SMD	SMD	SMD	SMD — From same series, package is likely identical. Verify dimensions.; 045106.3MRL: Package type matches, but dimensions must be verified.; 0453010.MR: Package type matches, but dimensions must be verified.
Response Time	Very Fast-Acting	Very Fast-Acting	Very Fast-Acting	Very Fast-Acting	Very Fast-Acting — Response time characteristic matches.; 045106.3MRL: Response time characteristic matches.; 0453010.MR: Response time characteristic matches.
Pinout	null	null	2	2	null / 2 — Pin count data missing for both. Datasheet check required for pin compatibility.; 045106.3MRL: Target pin count is unknown. Pin compatibility requires datasheet review.; 0453010.MR: Target pin count is unknown. Pin compatibility requires datasheet review.

Application & sourcing insights

Questions & answers

There are no direct drop-in replacements found. Alternatives like 0451007.MRL exist within the same Littelfuse 451 series but have higher current ratings, requiring careful engineering review.