Littelfuse 061702.5MXP Glass Cartridge Fuse 2.5A 250VAC 5x20mm Equivalent & Substitute Parts

Part Overview

The Littelfuse 061702.5MXP is a fast-blow glass cartridge fuse rated at 2.5A, 250VAC, with a 5mm x 20mm form factor. This component is designed for circuit protection in AC and DC applications requiring rapid response to overcurrent conditions. The part is active in production with 4,100 units in stock. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, response characteristics, and regulatory compliance standards.

Key Parameters

Parameter	Value
Current Rating	2.5 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Fast Blow
Package / Case	5mm x 20mm
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitution eligibility for the 061702.5MXP is determined by the following critical parameters:

Primary Matching Criteria:

Current Rating: 2.5 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Response Time: Fast Blow (exact match required)
Mounting Type: Requires Holder (exact match required)

Secondary Compatibility Factors:

Operating Temperature Range: -55°C to 125°C (must encompass or match)
RoHS Compliance: ROHS3 Compliant (preferred for regulatory alignment)
Product Status: Active (ensures ongoing availability)

All identified substitute parts meet these primary criteria. Variations in Breaking Capacity, Melting I²t, DC Cold Resistance, and approval agency certifications do not preclude substitution when primary electrical and mechanical parameters are identical.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating (A)	Voltage Rating (V AC)	Response Time	Package	Breaking Capacity @ Rated Voltage (A)	Melting I²t	DC Cold Resistance (Ohms)	Operating Temperature	Inventory (Pcs)
061702.5MXP	Littelfuse Inc.	617	2.5	250	Fast Blow	5mm x 20mm	35	9.46	0.0334	-55°C ~ 125°C	4,100
021702.5HXP	Littelfuse Inc.	217	2.5	250	Fast Blow	5mm x 20mm	35	9.46	0.0334	-55°C ~ 125°C	3,507
021702.5MXP	Littelfuse Inc.	217	2.5	250	Fast Blow	5mm x 20mm	35	9.46	0.0334	-55°C ~ 125°C	3,295
023502.5HXP	Littelfuse Inc.	235	2.5	250	Fast Blow	5mm x 20mm	100	5.445	0.0437	-55°C ~ 125°C	8,618
023502.5MXP	Littelfuse Inc.	235	2.5	250	Fast Blow	5mm x 20mm	100	5.445	0.0437	-55°C ~ 125°C	1,690
0034.1520	SCHURTER Inc.	FSF 5x20	2.5	250	Fast Blow	5mm x 20mm	35	9.19	—	-55°C ~ 125°C	15,718
FSD-2.5A	OptiFuse	FSD	2.5	250	Fast Blow	5mm x 20mm	35	13.69	—	-55°C ~ 125°C	3,159

Engineering Selection Recommendations

Littelfuse Series 217 (021702.5HXP, 021702.5MXP): These parts are direct Littelfuse alternatives within the same manufacturer ecosystem. Both maintain identical electrical characteristics and thermal performance to the 061702.5MXP. Series 217 components carry expanded regulatory approvals including BSI, KC, PSE, and SEMKO, providing broader international compliance coverage. Selection between HXP and MXP variants depends on specific application requirements and regional certification needs.

Littelfuse Series 235 (023502.5HXP, 023502.5MXP): These parts meet all primary substitution criteria with enhanced breaking capacity (100A versus 35A). The Series 235 variants exhibit lower melting I²t values (5.445 versus 9.46), indicating faster thermal response. These parts are suitable for applications requiring higher fault current withstand capability. Regulatory approvals include CE, CSA, KC, PSE, and UL. Higher inventory availability (8,618 and 1,690 units) supports supply chain flexibility.

SCHURTER 0034.1520: This cross-manufacturer substitute from SCHURTER Inc. (FSF 5x20 series) provides electrical and mechanical equivalence with 35A breaking capacity and 9.19 melting I²t. The part carries CCC, cURus, PSE/JET, and VDE certifications. Notably, this part has the highest inventory level (15,718 units), supporting extended availability. Selection of this part requires confirmation of SCHURTER holder compatibility in the target application.

OptiFuse FSD-2.5A: This substitute from OptiFuse meets all primary electrical and mechanical requirements with 35A breaking capacity. The FSD series exhibits the highest melting I²t value (13.69), indicating slower thermal response compared to other alternatives. Regulatory approvals include cURus and IEC 60127. This part is suitable for applications where extended thermal response time is acceptable or beneficial.

Frequently Asked Questions (FAQ)

Q: Can I substitute the 061702.5MXP with any of these equivalent parts without circuit redesign?

A: Yes. All listed substitute parts match the critical parameters: 2.5A current rating, 250V AC voltage rating, 5mm x 20mm package, fast-blow response, and cartridge glass fuse type. Physical installation requires a compatible 5x20mm fuse holder. No circuit modifications are necessary.

Q: What is the difference between the Littelfuse Series 617, 217, and 235?

A: All three series share identical electrical ratings (2.5A, 250V) and package dimensions. The primary differences are breaking capacity and melting I²t characteristics. Series 617 and 217 have 35A breaking capacity with 9.46 melting I²t. Series 235 has 100A breaking capacity with 5.445 melting I²t, providing faster thermal response and higher fault current withstand. Series 235 carries UL certification in addition to other approvals.

Q: Are there regulatory compliance differences between these substitutes?

A: Yes. The 061702.5MXP carries CCC, CE, CSA, UR, and VDE approvals. Series 217 parts add BSI, KC, PSE, and SEMKO certifications. Series 235 parts carry CE, CSA, KC, PSE, and UL approvals. SCHURTER 0034.1520 includes CCC, cURus, PSE/JET, and VDE. OptiFuse FSD-2.5A includes cURus and IEC 60127. Selection should align with target market regulatory requirements.

Q: What does melting I²t indicate, and why does it vary among these parts?

A: Melting I²t is a thermal characteristic indicating the energy required to melt the fuse element. Lower values (Series 235 at 5.445) indicate faster thermal response to overcurrent. Higher values (OptiFuse FSD at 13.69) indicate slower response. The 061702.5MXP and Series 217 at 9.46 represent intermediate response. Application requirements determine the appropriate thermal characteristic.

Q: Can I use SCHURTER 0034.1520 or OptiFuse FSD-2.5A in a Littelfuse fuse holder?

A: Physical compatibility depends on holder design. All three manufacturers produce 5mm x 20mm cartridge fuses meeting standard dimensional specifications. However, holder contact geometry and spring tension may vary by manufacturer. Confirm mechanical fit with the specific holder model before substitution.

Q: Which substitute offers the best inventory availability?

A: SCHURTER 0034.1520 has the highest inventory at 15,718 units. Littelfuse Series 235 (023502.5HXP) has 8,618 units. For Littelfuse Series 217, 021702.5HXP has 3,507 units and 021702.5MXP has 3,295 units. OptiFuse FSD-2.5A has 3,159 units.

Q: Are all these parts RoHS3 compliant?

A: Yes. The 061702.5MXP, all Littelfuse substitutes (Series 217 and 235), and OptiFuse FSD-2.5A are ROHS3 compliant. SCHURTER 0034.1520 is also ROHS3 compliant. All parts are REACH unaffected.

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