MICROSMD075-2 Equivalent & Substitute Parts

Part Overview

The MICROSMD075-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse Inc., rated for 6V maximum voltage with 750 mA hold current. This component is classified as Obsolete, which necessitates identification of active equivalent parts for new designs and ongoing production requirements. The part is housed in a 1210 (3225 Metric) surface mount package with concave geometry and meets CSA, TUV, and UL approval standards.

Key Parameters

Parameter	Value
Voltage - Max	6V
Current - Hold (Ih) (Max)	750 mA
Current - Trip (It)	1.5 A
Current - Max	40 A
Time to Trip	100 ms
Resistance - Initial (Ri) (Min)	110 mOhms
Resistance - Post Trip (R1) (Max)	400 mOhms
Mounting Type	Surface Mount
Package / Case	1210 (3225 Metric), Concave
Size / Dimension	0.127" L x 0.102" W (3.22mm x 2.58mm)
Thickness (Max)	0.024" (0.62mm)
Approval Agency	CSA, TUV, UL
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level (MSL)	2A (4 Weeks)

Substitute Part Grouping Explanation

Substitution of the MICROSMD075-2 is determined by strict equivalence across the following critical parameters:

Voltage rating: 6V maximum
Hold current (Ih): 750 mA maximum
Trip current (It): 1.5 A
Package type: 1210 (3225 Metric), Concave surface mount
Physical dimensions: 0.127" L x 0.102" W (3.22mm x 2.58mm)
Approval certifications: CSA, TUV, UL compliance

Two active substitute parts meet these criteria: MICROSMD075F-2 (Littelfuse Inc.) and MF-USMF075-2 (Bourns Inc.). Both maintain identical electrical performance specifications and package geometry, enabling direct functional replacement in circuit applications.

Parameter Comparison

Parameter	MICROSMD075-2	MICROSMD075F-2	MF-USMF075-2
Manufacturer	Littelfuse Inc.	Littelfuse Inc.	Bourns Inc.
Product Status	Obsolete	Active	Active
Voltage - Max	6V	6V	6V
Current - Hold (Ih) (Max)	750 mA	750 mA	750 mA
Current - Trip (It)	1.5 A	1.5 A	1.5 A
Current - Max	40 A	40 A	40 A
Time to Trip	100 ms	100 ms	100 ms
Resistance - Initial (Ri) (Min)	110 mOhms	110 mOhms	70 mOhms
Resistance - Post Trip (R1) (Max)	400 mOhms	400 mOhms	450 mOhms
Operating Temperature	Not specified	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave	1210 (3225 Metric), Concave
Size / Dimension	0.127" L x 0.102" W (3.22mm x 2.58mm)	0.127" L x 0.102" W (3.22mm x 2.58mm)	0.127" L x 0.102" W (3.22mm x 2.58mm)
Thickness (Max)	0.024" (0.62mm)	0.024" (0.62mm)	0.033" (0.85mm)
Approval Agency	CSA, TUV, UL	CSA, TUV, UL	cURus, TUV
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	2A (4 Weeks)	2A (4 Weeks)	1 (Unlimited)

Engineering Selection Recommendations

MICROSMD075F-2 is the primary substitute for MICROSMD075-2. Both parts are manufactured by Littelfuse Inc. within the PolySwitch microSMD series. MICROSMD075F-2 is Active status with ROHS3 compliance, addressing the obsolescence of the original part while maintaining identical electrical and mechanical specifications. This part is available in Cut Tape and Digi-Reel packaging with 25,200 units in stock.

MF-USMF075-2 (Bourns Inc., Multifuse series) serves as an alternative substitute. This part maintains all critical electrical parameters and package dimensions. Notable differences include lower initial resistance (70 mOhms vs. 110 mOhms), slightly higher post-trip resistance (450 mOhms vs. 400 mOhms), increased thickness (0.033" vs. 0.024"), and superior moisture sensitivity rating (MSL 1 vs. 2A). MF-USMF075-2 carries AEC-Q200 automotive qualification and is available in Tape & Reel packaging with 84,100 units in stock.

Selection between these substitutes depends on design requirements: MICROSMD075F-2 for direct Littelfuse continuity, or MF-USMF075-2 for automotive-qualified applications with enhanced moisture protection.

Frequently Asked Questions (FAQ)

Q: Can MICROSMD075F-2 directly replace MICROSMD075-2 in existing designs?

A: Yes. MICROSMD075F-2 maintains identical voltage rating (6V), hold current (750 mA), trip current (1.5 A), package geometry (1210 Concave), and physical dimensions (0.127" L x 0.102" W). Both parts meet CSA, TUV, and UL certifications. The primary difference is product status: MICROSMD075F-2 is Active while MICROSMD075-2 is Obsolete.

Q: What are the key differences between MICROSMD075F-2 and MF-USMF075-2?

A: Both parts share identical voltage, hold current, trip current, and package type. Differences include: initial resistance (110 mOhms vs. 70 mOhms), post-trip resistance (400 mOhms vs. 450 mOhms), thickness (0.024" vs. 0.033"), moisture sensitivity (2A vs. 1), and certifications (CSA/TUV/UL vs. cURus/TUV). MF-USMF075-2 includes AEC-Q200 automotive qualification.

Q: Does the thickness difference between MICROSMD075F-2 (0.024") and MF-USMF075-2 (0.033") affect PCB layout?

A: The 0.009" thickness difference may impact board clearance in space-constrained designs. MICROSMD075F-2 maintains the original thickness specification of 0.024", making it the preferred choice for designs with existing height constraints. MF-USMF075-2 requires verification of available vertical clearance.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both MICROSMD075F-2 and MF-USMF075-2 are ROHS3 compliant, addressing the RoHS non-compliance status of the original MICROSMD075-2.

Q: Which substitute part has better moisture protection?

A: MF-USMF075-2 carries MSL 1 (Unlimited moisture sensitivity level), compared to MSL 2A (4 Weeks) for both MICROSMD075-2 and MICROSMD075F-2. This provides superior moisture protection for applications requiring extended storage or high-humidity environments.

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