MLF2012A3R9MT Equivalent & Substitute Parts

Part Overview

The MLF2012A3R9MT is a 3.9 µH shielded multilayer inductor manufactured by TDK Corporation in 0805 (2012 Metric) surface mount package. This component is rated for 30 mA maximum current with 650 mOhm maximum DC resistance and operates across -55°C to 125°C. The part carries a "Not For New Designs" product status, indicating it has been superseded in TDK's current product portfolio. Identifying equivalent substitute parts is necessary for ongoing production support, legacy system maintenance, and design continuity where this inductance value and package specification are required.

Key Parameters

Parameter	Value
Inductance	3.9 µH
Current Rating	30 mA
DC Resistance (Max)	650 mOhm
Package / Case	0805 (2012 Metric)
Shielding	Shielded
Material - Core	Ferrite
Operating Temperature Range	-55°C ~ 125°C
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution eligibility for the MLF2012A3R9MT is determined by strict equivalence across the following critical parameters:

Inductance Value: Must be 3.9 µH (tolerance variations are acceptable within engineering specifications)
Current Rating: Must support minimum 30 mA
DC Resistance: Must not exceed 650 mOhm maximum
Package: Must be 0805 (2012 Metric) surface mount
Core Material: Must be ferrite-based
Shielding: Must be shielded construction
Temperature Range: Must cover -55°C to 125°C minimum

The MLF2012A3R9KTD25 meets all substitution criteria as a direct equivalent part from the same manufacturer series, with identical electrical performance specifications and mechanical compatibility.

Parameter Comparison

Parameter	MLF2012A3R9MT	MLF2012A3R9KTD25	Compatibility
Manufacturer	TDK Corporation	TDK Corporation	Match
Series	MLF	MLF	Match
Inductance	3.9 µH	3.9 µH	Match
Tolerance	±20%	±10%	Substitute is tighter
Current Rating (Amps)	30 mA	30 mA	Match
DC Resistance (Max)	650 mOhm	650 mOhm	Match
Q @ 10MHz	45	45	Match
Frequency - Self Resonant	55 MHz	55 MHz	Match
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	Match
Package / Case	0805 (2012 Metric)	0805 (2012 Metric)	Match
Size / Dimension	0.079" L x 0.049" W (2.00mm x 1.25mm)	0.079" L x 0.049" W (2.00mm x 1.25mm)	Match
Height - Seated (Max)	0.057" (1.45mm)	0.057" (1.45mm)	Match
Shielding	Shielded	Shielded	Match
Material - Core	Ferrite	Ferrite	Match
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Match
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Match
REACH Status	REACH Unaffected	REACH Unaffected	Match
Product Status	Not For New Designs	Active	Substitute is current

Engineering Selection Recommendations

The MLF2012A3R9KTD25 is the direct substitute for MLF2012A3R9MT applications. Selection rationale is based on the following factors:

Product Status: The MLF2012A3R9KTD25 carries Active product status, ensuring ongoing manufacturer support, availability, and compliance maintenance. The original MLF2012A3R9MT is designated "Not For New Designs," making the substitute the appropriate choice for current production and long-term supply chain stability.

Compliance & Certifications: Both parts maintain ROHS3 compliance and REACH Unaffected status. The MLF2012A3R9KTD25 includes AEC-Q200 automotive qualification, providing additional reliability assurance for applications requiring automotive-grade components.

Electrical Equivalence: All critical electrical parameters are identical: 3.9 µH inductance, 30 mA current rating, 650 mOhm maximum DC resistance, 45 Q factor at 10 MHz, and 55 MHz self-resonant frequency. The substitute features tighter inductance tolerance (±10% versus ±20%), which provides improved consistency without introducing compatibility concerns.

Mechanical & Thermal Compatibility: Package dimensions, height, operating temperature range, and mounting type are identical, ensuring direct PCB layout compatibility and thermal performance equivalence.

Frequently Asked Questions (FAQ)

Q: Can MLF2012A3R9KTD25 be used as a direct replacement for MLF2012A3R9MT in existing designs?

A: Yes. The MLF2012A3R9KTD25 is electrically and mechanically equivalent. All critical parameters—inductance, current rating, DC resistance, package dimensions, and operating temperature—are identical. The substitute can be used without PCB redesign or circuit modification.

Q: What is the difference between the ±20% tolerance of MLF2012A3R9MT and the ±10% tolerance of MLF2012A3R9KTD25?

A: The MLF2012A3R9KTD25 provides tighter inductance tolerance, meaning the actual inductance value will be closer to the nominal 3.9 µH specification. This improves circuit performance consistency and reduces design margin requirements. This is a beneficial improvement, not a limitation.

Q: Why is MLF2012A3R9MT marked "Not For New Designs"?

A: This designation indicates the part has been superseded in TDK's current product portfolio. The MLF2012A3R9KTD25 is the active replacement. For new designs, the substitute should be specified. For legacy systems, the substitute provides continuity with improved product status and ongoing support.

Q: Are the physical dimensions identical between these parts?

A: Yes. Both parts use the 0805 (2012 Metric) package with identical length (0.079" / 2.00mm), width (0.049" / 1.25mm), and maximum seated height (0.057" / 1.45mm). They are footprint-compatible with no PCB layout modifications required.

Q: Does the MLF2012A3R9KTD25 include automotive qualification?

A: Yes. The MLF2012A3R9KTD25 carries AEC-Q200 automotive qualification, whereas the original MLF2012A3R9MT does not list this certification. This makes the substitute suitable for automotive and high-reliability applications.

Q: Are both parts RoHS and REACH compliant?

A: Yes. Both MLF2012A3R9MT and MLF2012A3R9KTD25 are ROHS3 compliant and REACH Unaffected, meeting current environmental and regulatory requirements.

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