Littelfuse 0219.125M Equivalent & Substitute Parts

Part Overview

The Littelfuse 0219.125M is a 125 mA, 250 V AC/DC slow-blow glass cartridge fuse in a 5mm x 20mm form factor. This part is classified as obsolete, requiring identification of active equivalent alternatives for new designs and ongoing applications. Substitute parts maintain the same electrical ratings, physical dimensions, and functional characteristics while offering improved availability and compliance status.

Key Parameters

Parameter	Value
Current Rating	125 mA
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

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (125 mA), voltage rating (250 V AC), response time (slow blow), physical dimensions (5mm x 20mm), fuse type (cartridge glass), and operating temperature range (-55°C to 125°C). All listed substitute parts meet these core electrical and mechanical requirements.

Substitute parts are grouped into two categories based on breaking capacity at rated voltage:

Category A: 35A Breaking Capacity — Series 218 and 239 parts (0218.125HXP, 0218.125MX8810P, 0218.125MXBP, 0218.125MXP, 0218.125TXP, 0218.125VXP, 0239.125MXP)

Category B: 150A Breaking Capacity — Series 219XA parts (0219.125MXABP, 0219.125MXAP, 0219.125TXAP)

The original 0219.125M has 150A breaking capacity; Category B substitutes maintain this specification. Category A substitutes provide equivalent electrical function with reduced breaking capacity suitable for applications not requiring 150A specification.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating	Voltage (AC)	Response Time	Package	Breaking Capacity @ Rated Voltage	Melting I²t	DC Cold Resistance (Ω)	Product Status	RoHS Status
0219.125M	Littelfuse Inc.	219	125 mA	250 V	Slow Blow	5mm x 20mm	150 A	0.15	4.41	Obsolete	Non-compliant
0218.125HXP	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0218.125MX8810P	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0218.125MXBP	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0218.125MXP	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0218.125TXP	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0218.125VXP	Littelfuse Inc.	218	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.1465	4.2	Active	ROHS3 Compliant
0219.125MXABP	Littelfuse Inc.	219XA	125 mA	250 V	Slow Blow	5mm x 20mm	150 A	0.13	4.2	Active	ROHS3 Compliant
0219.125MXAP	Littelfuse Inc.	219XA	125 mA	250 V	Slow Blow	5mm x 20mm	150 A	0.13	4.2	Active	ROHS3 Compliant
0219.125TXAP	Littelfuse Inc.	219XA	125 mA	250 V	Slow Blow	5mm x 20mm	150 A	0.13	4.2	Active	ROHS3 Compliant
0239.125MXP	Littelfuse Inc.	239	125 mA	250 V	Slow Blow	5mm x 20mm	35 A	0.085	11.6	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: 0219.125MXAP

The 0219.125MXAP is the preferred direct substitute for the obsolete 0219.125M. Both parts maintain 150A breaking capacity, identical electrical ratings, and equivalent thermal characteristics. The 0219.125MXAP is active in production, ROHS3 compliant, and carries broader approval agency certifications (CCC, CE, CSA, SEMKO, UL, VDE). Inventory availability is substantial at 3,538 units.

Alternative Recommendation: 0219.125MXABP or 0219.125TXAP

These Series 219XA alternatives provide identical 150A breaking capacity and electrical specifications. Both are active products with full RoHS3 compliance. Selection between these three 150A options depends on packaging requirements and internal design specifications.

Secondary Recommendation: 0218.125MXP

For applications where 35A breaking capacity is acceptable, the 0218.125MXP offers the highest inventory availability (19,944 units) and active production status. This part maintains all core electrical parameters and operates within the same temperature range. Melting I²t is slightly lower (0.1465 vs. 0.15), and DC cold resistance is reduced (4.2 vs. 4.41 Ohms), representing minor thermal performance differences suitable for most general-purpose applications.

Not Recommended: 0239.125MXP

While electrically equivalent, this part exhibits significantly higher DC cold resistance (11.6 Ohms vs. 4.41 Ohms) and lower melting I²t (0.085), indicating different thermal response characteristics. Selection should be limited to applications specifically designed for Series 239 performance profiles.

Frequently Asked Questions (FAQ)

Q: Can I use a 35A breaking capacity fuse as a substitute for the original 150A breaking capacity part?

A: Breaking capacity determines the maximum fault current the fuse can safely interrupt. If your application circuit design requires 150A breaking capacity for safety compliance, use only 150A-rated substitutes (0219.125MXAP, 0219.125MXABP, or 0219.125TXAP). For applications with lower fault current levels, 35A-rated alternatives are electrically compatible.

Q: What is the difference between Series 218, 219, 219XA, and 239?

A: These series designations reflect different product lines within Littelfuse's cartridge fuse portfolio. All listed parts share identical electrical ratings (125 mA, 250 V AC, slow blow) and physical dimensions (5mm x 20mm). Series differences relate to breaking capacity, thermal characteristics (melting I²t), and approval agency certifications. Series 219XA represents the active replacement for the obsolete Series 219.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts listed are ROHS3 compliant. The original 0219.125M is RoHS non-compliant, making the transition to compliant alternatives necessary for new designs and regulatory requirements.

Q: Does DC cold resistance affect fuse performance?

A: DC cold resistance influences voltage drop across the fuse during normal operation and affects thermal response characteristics. The original part (4.41 Ohms) and most substitutes (4.2 Ohms) are closely matched. The 0239.125MXP exhibits significantly higher resistance (11.6 Ohms), resulting in different thermal behavior and should only be selected for applications specifically designed for this characteristic.

Q: What approval agencies are relevant for my application?

A: Approval requirements depend on your end-use market and regional regulations. The 0219.125MXAP carries certifications from CCC, CE, CSA, SEMKO, UL, and VDE, covering major global markets. Verify that your application's required certifications are present on the selected substitute part.

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