RGEF400K-AP Equivalent & Substitute Parts

Part Overview

The RGEF400K-AP is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., part of the PolySwitch® RGEF series. This component provides overcurrent protection in through-hole radial configuration with a 16V maximum voltage rating and 4A hold current specification. The device is actively produced and widely used in circuit protection applications requiring automatic reset functionality after fault conditions are cleared. Substitute parts are identified when identical electrical and mechanical parameters are maintained across the product line, ensuring direct interchangeability without circuit redesign.

Substiute Parts

RGEF400K-AP

Littelfuse Inc.In Stock: 1479RGEF400K-AP Datasheet

Current PartRFQ

RGEF400-AP

LittelfuseIn Stock: 3999RGEF400-AP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RGEF400K-AP is determined by strict equivalence across the following critical parameters:

• Voltage rating (16V maximum)
• Hold current specification (4A maximum)
• Trip current value (6.8A)
• Maximum current capacity (100A)
• Trip time characteristic (1.7s)
• Initial and post-trip resistance values
• Operating temperature range (-40°C to 85°C)
• Through-hole radial mounting configuration
• Physical dimensions and lead spacing
• Regulatory compliance (CSA, TUV, UL certifications)
• RoHS3 compliance status

The RGEF400-AP meets all substitution criteria as a direct equivalent within the PolySwitch® RGEF series, maintaining identical electrical performance and mechanical compatibility with the RGEF400K-AP.

Parameter Comparison

Engineering Selection Recommendations

Both the RGEF400K-AP and RGEF400-AP are active production components from Littelfuse Inc. with identical electrical specifications and mechanical configurations. Selection between these parts is based on availability and packaging format (Cut Tape). Both components carry CSA, TUV, and UL certifications, meeting industrial safety and compliance requirements. ROHS3 compliance is maintained across both variants, ensuring regulatory conformance in restricted substance applications. The RGEF400-AP currently maintains higher inventory availability (3935 Pcs) compared to the RGEF400K-AP (1463 Pcs), which may influence procurement decisions based on lead time requirements.

Frequently Asked Questions (FAQ)

Q: Can RGEF400-AP be used as a direct replacement for RGEF400K-AP?

A: Yes. Both parts are electrically and mechanically identical, with matching voltage ratings (16V), hold current (4A), trip current (6.8A), operating temperature range (-40°C to 85°C), and physical dimensions. Both are through-hole radial configuration with identical lead spacing (5.05mm).

Q: Are there differences in regulatory certifications between these parts?

A: No. Both RGEF400K-AP and RGEF400-AP carry identical certifications from CSA, TUV, and UL, and both comply with ROHS3 requirements.

Q: What determines substitution eligibility for PTC resettable fuses?

A: Substitution requires matching voltage rating, hold current, trip current, maximum current capacity, trip time, initial and post-trip resistance values, operating temperature range, mounting type, physical dimensions, and regulatory compliance status.

Q: Does packaging format affect electrical performance?

A: No. Both parts are supplied in Cut Tape (CT) packaging. Packaging format does not affect electrical characteristics or performance.

Q: Are there any lead time considerations when selecting between these substitutes?

A: The RGEF400-AP has higher current inventory (3935 Pcs) versus RGEF400K-AP (1463 Pcs). Availability may influence procurement timelines based on project requirements.