Littelfuse 021302.5TXP Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 021302.5TXP is a 2.5 A, 250 V AC/DC glass cartridge fuse in 5mm x 20mm package format with slow-blow response characteristics. This fuse is designed for circuit protection in applications requiring holder-mounted cartridge fuses. The part maintains active product status with 834 units in current inventory. Equivalent and substitute parts are identified for applications where specific series variants, availability, or performance characteristics necessitate alternative component selection while maintaining electrical and mechanical compatibility.

Key Parameters

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

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters: current rating (2.5 A), voltage rating (250 V AC), package dimensions (5mm x 20mm), fuse type (cartridge glass), response time (slow blow), and mounting requirement (holder-mounted). All identified substitute parts match these core electrical and mechanical specifications. Variations in breaking capacity, melting I²t, DC cold resistance, and approval agency certifications are documented but do not preclude substitution when application requirements align with the specified parameters. Series designation changes (213, 218, 219XA, 239, FST, SMD-FST, SMD-FTT, TSC) reflect manufacturer product line organization and do not affect functional equivalence within the defined parameter set.

Parameter Comparison

Part Number	Manufacturer	Series	Current (A)	Voltage (V AC)	Package	Response Time	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Inventory (Pcs)
021302.5TXP	Littelfuse Inc.	213	2.5	250	5x20mm	Slow Blow	35	138	0.0305	834
021302.5MXP	Littelfuse Inc.	213	2.5	250	5x20mm	Slow Blow	35	138	0.0305	1732
021802.5HXP	Littelfuse	218	2.5	250	5x20mm	Slow Blow	35	23.25	0.0219	21272
021802.5TXP	Littelfuse Inc.	218	2.5	250	5x20mm	Slow Blow	35	23.25	0.0219	880
021902.5MXAP	Littelfuse	219XA	2.5	250	5x20mm	Slow Blow	150	138	0.0305	1000
023902.5HXP	Littelfuse	239	2.5	250	5x20mm	Slow Blow	100	79.705	0.0583	2200
023902.5MXP	Littelfuse	239	2.5	250	5x20mm	Slow Blow	100	79.705	0.0583	3140
0034.3121	SCHURTER Inc.	FST 5x20	2.5	250	5x20mm	Slow Blow	35	21.9	—	2136
0034.5621.11	SCHURTER Inc.	SMD-FST	2.5	250	5x20mm	Slow Blow	35	21.9	—	1013
0034.5717.11	SCHURTER Inc.	SMD-FTT	2.5	250	5x20mm	Slow Blow	35	258	—	1388
TSC-2.5A	OptiFuse	TSC	2.5	250	5x20mm	Slow Blow	100	24.49	—	2361

Engineering Selection Recommendations

All listed substitute parts satisfy the core electrical and mechanical requirements for direct substitution with the 021302.5TXP. Selection among equivalents should be based on the following criteria:

Littelfuse Series 213 (021302.5TXP, 021302.5MXP): Identical electrical characteristics and breaking capacity. Series 213 parts carry approvals from BSI, CCC, CE, CSA, PSE, SEMKO, UR, and VDE. The 021302.5MXP variant offers higher inventory availability (1732 units).

Littelfuse Series 218 (021802.5HXP, 021802.5TXP): Lower melting I²t (23.25 vs. 138) and reduced DC cold resistance (0.0219 Ω vs. 0.0305 Ω). Series 218 parts carry approvals from CCC, CE, CSA, K-MARK, PSE, SEMKO, UL, and VDE. The 021802.5HXP variant provides significantly higher inventory (21272 units).

Littelfuse Series 219XA (021902.5MXAP): Elevated breaking capacity (150 A vs. 35 A) with identical melting I²t and DC cold resistance to the main part. Carries approvals from CCC, CE, CSA, PSE, SEMKO, UL, and VDE.

Littelfuse Series 239 (023902.5HXP, 023902.5MXP): Intermediate breaking capacity (100 A) with melting I²t of 79.705 and elevated DC cold resistance (0.0583 Ω). Carries approvals from CE, CSA, KC, PSE, and UL. The 023902.5MXP variant offers highest inventory among Series 239 (3140 units).

SCHURTER FST Series (0034.3121, 0034.5621.11, 0034.5717.11): Cross-manufacturer equivalents with 35 A breaking capacity. Series FST and SMD-FST carry approvals from CCC, cURus, PSE/JET, and VDE. Series SMD-FTT (0034.5717.11) features elevated melting I²t (258) and carries cURus approval.

OptiFuse TSC Series (TSC-2.5A): 100 A breaking capacity with melting I²t of 24.49. Carries cULus and UL 248 approvals. HTSUS classification differs (8535.10.0040 vs. 8536.10.0020).

All substitute parts maintain ROHS3 compliance and -55°C to 125°C operating temperature range.

Frequently Asked Questions (FAQ)

Q: Can the 021302.5TXP be directly replaced with any of the listed substitute parts?

A: Yes. All listed parts share identical current rating (2.5 A), voltage rating (250 V AC), package dimensions (5mm x 20mm), fuse type (cartridge glass), response time (slow blow), and mounting requirement (holder-mounted). Physical and electrical compatibility is maintained across all substitutes.

Q: What is the significance of different breaking capacity values among the substitutes?

A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt without rupturing the cartridge. The main part and most substitutes are rated at 35 A breaking capacity. Series 219XA (150 A) and Series 239 (100 A) variants provide higher fault current handling capability. Selection depends on the maximum prospective short-circuit current in the application circuit.

Q: How do melting I²t differences affect substitution?

A: Melting I²t characterizes the thermal energy required to melt the fuse element. Lower values (Series 218 at 23.25, SCHURTER FST at 21.9) indicate faster thermal response. Higher values (Series 213 at 138, SCHURTER SMD-FTT at 258) indicate slower thermal response. The slow-blow designation applies to all parts, but I²t variations reflect design differences within the slow-blow category. Application thermal requirements determine appropriate selection.

Q: Are there approval agency differences that affect substitution?

A: Yes. The main part carries approvals from BSI, CCC, CE, CSA, PSE, SEMKO, UR, and VDE. Substitute parts carry varying approval combinations. Series 218 includes K-MARK and UL approvals. Series 239 includes KC and UL approvals. OptiFuse TSC includes cULus and UL 248 approvals. SCHURTER parts include cURus approvals. Verify that the selected substitute carries all approvals required by the application's regulatory jurisdiction.

Q: What is the difference between Littelfuse and SCHURTER fuses in this category?

A: Both manufacturers produce functionally equivalent 2.5 A, 250 V, 5x20mm glass cartridge fuses with slow-blow response. SCHURTER parts (0034 series) are cross-manufacturer alternatives with comparable electrical characteristics. Selection may be driven by supply chain, approval requirements, or inventory availability rather than functional differences.

Q: Does DC cold resistance variation affect circuit performance?

A: DC cold resistance values range from 0.0219 Ω (Series 218) to 0.0583 Ω (Series 239). These resistances are negligible in typical circuit applications and do not materially affect circuit performance. Selection based on DC cold resistance is not necessary unless the application involves precision low-voltage circuits where minimal voltage drop across the fuse is critical.

Q: Can the OptiFuse TSC-2.5A be used as a direct substitute despite different HTSUS classification?

A: Yes. HTSUS classification is a tariff and trade classification code that does not affect electrical or mechanical compatibility. The TSC-2.5A maintains identical current, voltage, package, and response time specifications. HTSUS differences reflect administrative classification only and do not preclude substitution.

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