Littelfuse 021906.3M Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 021906.3M is a 6.3 A, 250 V AC/DC slow-blow glass cartridge fuse in 5mm x 20mm form factor, designed for applications requiring holder-mounted protection. This part is classified as obsolete. Due to its obsolete status, equivalent substitute parts from active product lines are necessary to maintain design continuity and ensure ongoing component availability for new production and field replacements.

Key Parameters

Parameter	Value
Current Rating	6.3 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Package / Case	5mm x 20mm
Fuse Type	Cartridge, Glass
Mounting Type	Requires Holder
Operating Temperature Range	-55°C to 125°C
Breaking Capacity @ Rated Voltage	150 A
Melting I²t	204
DC Cold Resistance	0.0075 Ohms

Substitute Part Grouping Explanation

Substitute parts for the 021906.3M are selected based on strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

Current Rating: 6.3 A (exact match required)
Voltage Rating: 250 V AC (exact match required)
Response Time: Slow Blow (exact match required)
Package / Case: 5mm x 20mm (exact match required)
Fuse Type: Cartridge, Glass (exact match required)
Mounting Type: Requires Holder (exact match required)
Operating Temperature Range: -55°C to 125°C (exact match required)

All substitute parts listed meet these core electrical and mechanical parameters. Variations in Breaking Capacity, Melting I²t, DC Cold Resistance, and approval certifications are noted but do not preclude substitution when electrical performance requirements are satisfied.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating (A)	Voltage (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	Product Status	RoHS Status
021906.3M	Littelfuse Inc.	219	6.3	250	Slow Blow	5mm x 20mm	150	204	0.0075	Obsolete	RoHS Non-Compliant
021306.3MXBP	Littelfuse Inc.	213	6.3	250	Slow Blow	5mm x 20mm	63	600	0.0095	Active	ROHS3 Compliant
021306.3MXP	Littelfuse Inc.	213	6.3	250	Slow Blow	5mm x 20mm	63	600	0.0095	Active	ROHS3 Compliant
021306.3TXP	Littelfuse Inc.	213	6.3	250	Slow Blow	5mm x 20mm	63	600	0.0095	Active	ROHS3 Compliant
021806.3HXP	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3MXBP	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3MXF11P	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3MXF34P	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3MXP	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3TXP	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant
021806.3VXP	Littelfuse Inc.	218	6.3	250	Slow Blow	5mm x 20mm	63	198.5	0.0076	Active	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts satisfy the core electrical and mechanical requirements for direct replacement of the 021906.3M. Selection among active alternatives should prioritize:

Product Status: All substitute parts carry Active product status, ensuring long-term availability and supply chain continuity compared to the obsolete 021906.3M.

Regulatory Compliance: Substitute parts from Series 213 and Series 218 are ROHS3 compliant, meeting current environmental and regulatory requirements. The original 021906.3M is RoHS non-compliant and should be phased out in new designs.

Certification Coverage: Series 218 parts (021806.3HXP, 021806.3MXBP, 021806.3MXF11P, 021806.3MXF34P, 021806.3MXP, 021806.3TXP, 021806.3VXP) carry certifications including CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE. Series 213 parts (021306.3MXBP, 021306.3MXP, 021306.3TXP) carry certifications including BSI, CCC, CE, CSA, PSE, SEMKO, UR, and VDE. Selection depends on target market regulatory requirements.

Inventory Availability: Series 218 parts, particularly 021806.3MXP (2,743 pcs), offer the highest stock levels for immediate procurement.

Frequently Asked Questions (FAQ)

Q: Can any of these substitute parts directly replace the 021906.3M without circuit modification?

A: Yes. All listed substitute parts match the 021906.3M in current rating (6.3 A), voltage rating (250 V AC), response time (slow blow), physical package (5mm x 20mm), and operating temperature range (-55°C to 125°C). No circuit modifications are required for electrical compatibility.

Q: What is the difference between Series 213 and Series 218 substitutes?

A: Series 213 parts (021306.3MXBP, 021306.3MXP, 021306.3TXP) have a Melting I²t of 600 and Breaking Capacity of 63 A. Series 218 parts have a Melting I²t of 198.5 and Breaking Capacity of 63 A. Both series meet the electrical requirements for the 021906.3M. Series 218 Melting I²t (198.5) is closer to the original part (204). Selection should be based on specific application thermal characteristics and certification requirements.

Q: Are there packaging differences among the substitute parts?

A: All substitute parts are supplied in bulk packaging. The physical form factor (5mm x 20mm cartridge, glass, requires holder) is identical across all parts. No holder or mounting hardware changes are necessary.

Q: Which substitute part should be selected for new product designs?

A: For new designs, select from active Series 218 parts with ROHS3 compliance and the required certifications for your target market. 021806.3MXP offers the highest inventory availability and comprehensive certification coverage (CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, VDE).

Q: Is the 021906.3M still available for purchase?

A: The 021906.3M is classified as obsolete. While 695 pcs are listed as in stock, this represents remaining inventory only. For ongoing production and field service, transition to an active substitute part to ensure long-term supply security.

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