MF-USML175/6-2 Equivalent & Substitute Parts

Part Overview

The MF-USML175/6-2 is a polymeric PTC resettable fuse manufactured by Bourns Inc. in the Multifuse® series. This surface mount component is rated for 6V maximum voltage with 1.75A hold current, packaged in 1210 (3225 Metric) form factor with concave profile. The part is active in production status and widely used in circuit protection applications requiring automatic reset capability. Equivalent and substitute parts are identified when electrical and mechanical parameters align within acceptable tolerances for the application requirements.

Key Parameters

Parameter	Value
Voltage - Max	6V
Current - Hold (Ih) (Max)	1.75 A
Current - Trip (It)	4.6 A
Current - Max	50 A
Time to Trip	800 ms
Resistance - Initial (Ri) (Min)	6 mOhms
Resistance - Post Trip (R1) (Max)	50 mOhms
Operating Temperature	-40°C ~ 85°C
Package / Case	1210 (3225 Metric), Concave
Size / Dimension	0.127" L x 0.101" W (3.22mm x 2.58mm)
Thickness (Max)	0.031" (0.80mm)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Approval Agency	cURus, TUV

Substitute Part Grouping Explanation

Substitute parts for the MF-USML175/6-2 are classified based on alignment with the following critical parameters:

Upgrade Substitute (MF-USML175/12-2): This Bourns part maintains identical electrical performance characteristics (1.75A hold current, 4.6A trip current, 800ms trip time, 6mOhms initial resistance) and mechanical specifications (1210 package, concave profile, identical dimensions). The voltage rating increases from 6V to 12V, providing higher voltage capability while preserving all other functional parameters. This part is suitable for applications where higher voltage tolerance is beneficial without compromising circuit protection performance.

Similar Substitute (PTSLR12106V175): This Eaton Electronics Division part matches the core voltage (6V) and current ratings (1.75A hold, 4.6A trip) with identical package form factor (1210, concave). Variations exist in time to trip (2.5s versus 800ms) and post-trip resistance (40mOhms maximum versus 50mOhms maximum), representing different thermal response characteristics within the polymeric PTC fuse category. Physical thickness differs slightly (0.028" versus 0.031"), remaining within surface mount assembly tolerances.

Parameter Comparison

Parameter	MF-USML175/6-2 (Main)	MF-USML175/12-2 (Upgrade)	PTSLR12106V175 (Similar)
Manufacturer	Bourns Inc.	Bourns Inc.	Eaton - Electronics Division
Voltage - Max	6V	12V	6V
Current - Hold (Ih) (Max)	1.75 A	1.75 A	1.75 A
Current - Trip (It)	4.6 A	4.6 A	4.6 A
Current - Max	50 A	50 A	50 A
Time to Trip	800 ms	800 ms	2.5 s
Resistance - Initial (Ri) (Min)	6 mOhms	6 mOhms	6 mOhms
Resistance - Post Trip (R1) (Max)	50 mOhms	50 mOhms	40 mOhms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave
Size / Dimension	0.127" L x 0.101" W (3.22mm x 2.58mm)	0.127" L x 0.101" W (3.22mm x 2.58mm)	0.127" L x 0.101" W (3.22mm x 2.58mm)
Thickness (Max)	0.031" (0.80mm)	0.031" (0.80mm)	0.028" (0.70mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	cUL, cURus, TUV	cURus, TUV
Product Status	Active	Active	Active

Engineering Selection Recommendations

All three parts maintain active production status and comply with ROHS3 environmental standards. The MF-USML175/6-2 and MF-USML175/12-2 share identical Bourns manufacturing lineage with cURus and TUV certifications, with the 12V variant adding cUL approval. The PTSLR12106V175 from Eaton maintains cURus and TUV certifications with equivalent compliance profile.

Selection between the main part and MF-USML175/12-2 depends on circuit voltage requirements. The 12V-rated upgrade provides enhanced voltage margin in systems operating at or near 6V nominal levels. Selection of PTSLR12106V175 is appropriate when Eaton component qualification is required or when the extended 2.5-second trip time characteristic aligns with application-specific protection timing requirements. All three parts are suitable for 1210 surface mount assembly processes with standard reflow profiles.

Frequently Asked Questions (FAQ)

Q: Can MF-USML175/12-2 replace MF-USML175/6-2 in a 6V circuit?

A: Yes. The MF-USML175/12-2 maintains identical hold current (1.75A), trip current (4.6A), and trip time (800ms) specifications. The higher voltage rating (12V) does not affect performance in 6V applications and provides additional voltage margin.

Q: What is the primary difference between MF-USML175/6-2 and PTSLR12106V175?

A: Both parts share 6V voltage rating, 1.75A hold current, and 4.6A trip current. The PTSLR12106V175 has a longer trip time (2.5s versus 800ms) and slightly lower post-trip resistance (40mOhms versus 50mOhms maximum). Physical thickness is 0.028" versus 0.031", remaining within surface mount assembly tolerances.

Q: Are all three parts compatible with standard 1210 surface mount assembly?

A: Yes. All three parts use 1210 (3225 Metric) concave package format with identical length and width dimensions (0.127" x 0.101"). Thickness variations (0.031" for Bourns parts, 0.028" for Eaton part) are within standard surface mount assembly tolerances.

Q: Which certifications apply to each part?

A: MF-USML175/6-2 carries cURus and TUV approvals. MF-USML175/12-2 carries cUL, cURus, and TUV approvals. PTSLR12106V175 carries cURus and TUV approvals. All parts comply with ROHS3 standards.

Q: Can PTSLR12106V175 be used where faster trip response is required?

A: No. The PTSLR12106V175 has a 2.5-second trip time compared to 800ms for the MF-USML175/6-2. Applications requiring the faster 800ms response must use the Bourns parts.

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