Littelfuse 021801.6TXP Glass Cartridge Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 021801.6TXP is a 1.6 A, 250 V AC/DC slow-blow glass cartridge fuse in 5mm × 20mm form factor. This fuse is designed for circuit protection in applications requiring slow-blow response characteristics and is actively manufactured. Equivalent and substitute parts are identified based on matching electrical ratings, mechanical dimensions, and functional performance parameters to ensure direct interchangeability or functional equivalence in circuit protection applications.

Key Parameters

Parameter	Specification
Current Rating	1.6 A
Voltage Rating (AC)	250 V
Response Time	Slow Blow
Package / Case	5mm × 20mm
Fuse Type	Cartridge, Glass
Mounting Type	Requires Holder
Breaking Capacity @ Rated Voltage	35 A
Operating Temperature Range	-55°C to 125°C
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the 021801.6TXP are grouped into three categories based on allowed electrical and mechanical parameters:

Category 1: Direct Series Equivalents (Littelfuse Series 218) Parts 021801.6HXP and 021801.6MXP share identical current rating, voltage rating, response time, package dimensions, and melting I²t value (23.35). These parts are mechanically and electrically interchangeable with the main part.

Category 2: Parametric Equivalents (Littelfuse Series 213, 219XA, 239, 618) Parts 021301.6MXP, 021301.6TXP, 021901.6MXABP, 021901.6MXAP, 023901.6HXP, 023901.6MXP, and 061801.6MXP match the core electrical parameters: 1.6 A current rating, 250 V AC voltage rating, slow-blow response, and 5mm × 20mm package. These parts differ in breaking capacity, melting I²t, approval agencies, or DC cold resistance but remain functionally equivalent for standard circuit protection applications.

Category 3: Cross-Manufacturer Equivalent (SCHURTER 0034.3119) The SCHURTER FST 5×20 series part 0034.3119 provides functional equivalence with matching current, voltage, response time, and package specifications, enabling cross-manufacturer substitution.

Parameter Comparison

Part Number	Manufacturer	Series	Current Rating (A)	Voltage Rating (V AC)	Response Time	Package	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ω)	Inventory (Pcs)
021801.6TXP	Littelfuse	218	1.6	250	Slow Blow	5×20mm	35	23.35	0.0336	704
021301.6MXP	Littelfuse	213	1.6	250	Slow Blow	5×20mm	35	44.2	0.0551	1001
021301.6TXP	Littelfuse	213	1.6	250	Slow Blow	5×20mm	35	44.2	0.0551	904
021801.6HXP	Littelfuse	218	1.6	250	Slow Blow	5×20mm	35	23.35	0.0336	1213
021801.6MXP	Littelfuse	218	1.6	250	Slow Blow	5×20mm	35	23.35	0.0336	2622
021901.6MXABP	Littelfuse	219XA	1.6	250	Slow Blow	5×20mm	150	44.2	0.0551	2757
021901.6MXAP	Littelfuse	219XA	1.6	250	Slow Blow	5×20mm	150	44.2	0.0551	2200
023901.6HXP	Littelfuse	239	1.6	250	Slow Blow	5×20mm	100	30.43	0.1205	2100
023901.6MXP	Littelfuse	239	1.6	250	Slow Blow	5×20mm	100	30.43	0.1205	5626
061801.6MXP	Littelfuse	618	1.6	250	Slow Blow	5×20mm	35	23.35	0.0336	10400
0034.3119	SCHURTER	FST 5×20	1.6	250	Slow Blow	5×20mm	35	10.5	—	8955

Engineering Selection Recommendations

Series 218 Direct Equivalents (021801.6HXP, 021801.6MXP) These parts are direct replacements for the 021801.6TXP with identical electrical performance and melting characteristics. Both are actively manufactured and ROHS3 compliant. Selection between these parts depends on availability and approval agency requirements. Part 021801.6MXP offers the highest inventory (2622 pcs).

Series 213 Alternatives (021301.6MXP, 021301.6TXP) These parts provide functional equivalence with higher melting I²t (44.2 vs. 23.35), resulting in slower thermal response. Both include PSE approval certification not present in the main part. These are suitable for applications where extended thermal tolerance is acceptable.

Series 219XA High Breaking Capacity (021901.6MXABP, 021901.6MXAP) These parts feature 150 A breaking capacity compared to 35 A in the main part, with higher melting I²t (44.2). Selection is appropriate for circuits requiring enhanced fault current handling. Both are actively manufactured with strong inventory levels.

Series 239 Medium Breaking Capacity (023901.6HXP, 023901.6MXP) These parts provide 100 A breaking capacity with intermediate melting I²t (30.43). Approval agencies differ from the main part (CE, CSA, KC, PSE, UL). Part 023901.6MXP has the highest inventory among Series 239 options (5626 pcs).

Series 618 (061801.6MXP) This Littelfuse part matches the main part's electrical and thermal characteristics with 35 A breaking capacity and 23.35 melting I²t. It offers the largest available inventory (10400 pcs) and is suitable for direct substitution.

Cross-Manufacturer Option (SCHURTER 0034.3119) The SCHURTER FST 5×20 series provides cross-manufacturer equivalence with matching current, voltage, and package specifications. Lower melting I²t (10.5) indicates faster thermal response. This part is suitable for applications where cross-manufacturer sourcing is required.

Frequently Asked Questions (FAQ)

Q: Can I use 021801.6HXP as a direct replacement for 021801.6TXP? A: Yes. Both parts are Littelfuse Series 218 with identical current rating (1.6 A), voltage rating (250 V AC), response time (slow blow), package (5×20mm), and melting I²t (23.35). They are mechanically and electrically interchangeable.

Q: What is the difference between Series 218 and Series 213 fuses? A: Series 213 parts have higher melting I²t (44.2 vs. 23.35), resulting in slower thermal response to overcurrent conditions. Both series share identical electrical ratings and package dimensions. Series 213 includes PSE approval certification.

Q: Why do some substitute parts have different breaking capacities? A: Breaking capacity indicates the maximum fault current the fuse can safely interrupt. Series 219XA parts (150 A) and Series 239 parts (100 A) provide enhanced fault current handling compared to Series 218 and 618 parts (35 A). Selection depends on circuit fault current requirements.

Q: Can I substitute the SCHURTER 0034.3119 for the Littelfuse 021801.6TXP? A: Yes, for applications requiring cross-manufacturer sourcing. Both parts match in current rating (1.6 A), voltage rating (250 V AC), response time (slow blow), and package (5×20mm). The SCHURTER part has lower melting I²t (10.5), indicating faster thermal response.

Q: What does melting I²t indicate? A: Melting I²t is a thermal characteristic that determines how quickly a fuse responds to overcurrent. Lower values indicate faster response; higher values indicate slower response. The main part (021801.6TXP) has melting I²t of 23.35, classified as slow blow.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All listed substitute parts are ROHS3 compliant, meeting environmental and material restriction requirements.

Q: Which substitute part has the best inventory availability? A: Part 061801.6MXP (Littelfuse Series 618) has the highest inventory at 10400 pcs, followed by 023901.6MXP (Series 239) at 5626 pcs.

Q: Do all substitute parts require a fuse holder? A: Yes. All listed parts are cartridge-type fuses requiring a holder for installation. The 5×20mm package dimension is standard across all parts.

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