MF-LSMF300X-2 Equivalent & Substitute Parts

Part Overview

The MF-LSMF300X-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 a 3A hold current and is housed in a 2920 (7351 Metric) package. The product is active and widely used in circuit protection applications requiring automatic reset functionality. Substitute parts are identified when equivalent electrical and mechanical parameters align within the allowed specifications for this product category, enabling component interchangeability in compatible applications.

Key Parameters

Parameter	Value
Voltage - Max	6V
Current - Hold (Ih) (Max)	3 A
Current - Trip (It)	5 A
Current - Max	40 A
Time to Trip	20 s
Resistance - Initial (Ri) (Min)	15 mOhms
Resistance - Post Trip (R1) (Max)	48 mOhms
Operating Temperature	-40°C ~ 85°C
Package / Case	2920 (7351 Metric), Concave
Size / Dimension	0.290" L x 0.202" W (7.36mm x 5.12mm)
Thickness (Max)	0.033" (0.85mm)
Mounting Type	Surface Mount
Type	Polymeric
RoHS Status	ROHS3 Compliant
Approval Agency	cURus, TUV

Substitute Part Grouping Explanation

Substitution eligibility for the MF-LSMF300X-2 is determined by the following critical parameters:

Mechanical Compatibility: Package type (2920 Concave), mounting type (Surface Mount), and physical dimensions (0.290" L x 0.202" W) must match to ensure PCB footprint compatibility.

Electrical Compatibility: Current hold rating (Ih) of 3A and time to trip of 20 seconds establish the functional protection profile. Post-trip resistance (R1 Max of 48 mOhms) ensures consistent performance characteristics.

Environmental & Compliance: Operating temperature range (-40°C ~ 85°C), RoHS3 compliance, and regulatory approvals (cURus, TUV) must be maintained.

The substitute part 0ZCF0300AF2C from Bel Fuse Inc. shares identical mechanical packaging, matching current hold specifications, and equivalent time-to-trip performance. Both components maintain the same operating temperature range and post-trip resistance maximum. Regulatory approvals and RoHS compliance are equivalent across both parts.

Parameter Comparison

Parameter	MF-LSMF300X-2 (Bourns)	0ZCF0300AF2C (Bel Fuse)
Voltage - Max	6V	15V
Current - Hold (Ih) (Max)	3 A	3 A
Current - Trip (It)	5 A	5.2 A
Current - Max	40 A	100 A
Time to Trip	20 s	20 s
Resistance - Initial (Ri) (Min)	15 mOhms	10 mOhms
Resistance - Post Trip (R1) (Max)	48 mOhms	48 mOhms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	2920 (7351 Metric), Concave	2920 (7351 Metric), Concave
Size / Dimension	0.290" L x 0.202" W (7.36mm x 5.12mm)	0.290" L x 0.202" W (7.36mm x 5.12mm)
Thickness (Max)	0.033" (0.85mm)	0.045" (1.15mm)
Mounting Type	Surface Mount	Surface Mount
Type	Polymeric	Polymeric
RoHS Status	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	cURus, TUV	AEC-Q200, cURus, TUV
Moisture Sensitivity Level (MSL)	1 (Unlimited)	2A (4 Weeks)

Engineering Selection Recommendations

Both the MF-LSMF300X-2 and 0ZCF0300AF2C are active products with ROHS3 compliance and regulatory approvals from cURus and TUV. The 0ZCF0300AF2C carries additional AEC-Q200 automotive qualification.

The primary distinction is voltage rating: the MF-LSMF300X-2 is rated for 6V maximum, while the 0ZCF0300AF2C is rated for 15V maximum. In applications operating at or below 6V, both components provide equivalent protection with matching hold current (3A) and trip time (20 seconds). The 0ZCF0300AF2C offers higher voltage headroom and greater maximum current capacity (100A vs. 40A), making it suitable for higher-voltage or higher-current applications.

Thickness differs between parts: 0.033" (0.85mm) for the MF-LSMF300X-2 versus 0.045" (1.15mm) for the 0ZCF0300AF2C. PCB assembly clearance must be verified for the thicker substitute. Moisture sensitivity level is higher for the 0ZCF0300AF2C (MSL 2A, 4 weeks) compared to the MF-LSMF300X-2 (MSL 1, unlimited), affecting storage and handling requirements.

Frequently Asked Questions (FAQ)

Q: Can the 0ZCF0300AF2C directly replace the MF-LSMF300X-2 in a 6V circuit?

A: Yes, in circuits operating at 6V or below. Both components share identical current hold ratings (3A), trip time (20 seconds), and post-trip resistance (48 mOhms maximum). The higher voltage rating of the 0ZCF0300AF2C does not prevent operation in lower-voltage applications.

Q: What is the impact of the thickness difference between these parts?

A: The MF-LSMF300X-2 has a maximum thickness of 0.033" (0.85mm), while the 0ZCF0300AF2C measures 0.045" (1.15mm). PCB layout and component clearance must accommodate the thicker substitute. Verify available board space before substitution.

Q: Are both parts suitable for automotive applications?

A: The 0ZCF0300AF2C carries AEC-Q200 automotive qualification. The MF-LSMF300X-2 does not list this certification. For automotive applications, the 0ZCF0300AF2C is the specified choice.

Q: How do moisture sensitivity levels affect component handling?

A: The MF-LSMF300X-2 (MSL 1) has unlimited shelf life under standard conditions. The 0ZCF0300AF2C (MSL 2A) requires controlled storage with a 4-week floor life after bag opening. Storage and handling procedures must reflect the higher moisture sensitivity of the substitute.

Q: Are the package footprints identical?

A: Yes. Both components use the 2920 (7351 Metric) Concave package with identical length (0.290") and width (0.202") dimensions. PCB footprints are compatible. Thickness variation must be the only layout consideration.

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