MH4532-121Y Ferrite Bead 120 Ohm 1812 Equivalent & Substitute Parts

Part Overview

The MH4532-121Y is a 120 Ohm ferrite bead in 1812 (4532 Metric) surface mount package manufactured by Bourns Inc. This component is rated for 3A maximum current with 50mOhm DC resistance and operates across -55°C to 125°C. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Ferrite beads in this specification are used for power and signal line filtering applications. Substitutes must maintain electrical performance at the specified impedance frequency while accommodating the mechanical constraints of the 1812 package footprint.

Key Parameters

Parameter	MH4532-121Y
Impedance @ Frequency	120 Ohms @ 100 MHz
Current Rating (Max)	3A
DC Resistance (DCR) (Max)	50mOhm
Package / Case	1812 (4532 Metric)
Operating Temperature	-55°C ~ 125°C
Mounting Type	Surface Mount
Size / Dimension	0.177" L x 0.126" W (4.50mm x 3.20mm)
Height (Max)	0.067" (1.70mm)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Mandatory Parameters (Must Match):

Impedance @ Frequency: 120 Ohms @ 100 MHz
Package / Case: 1812 (4532 Metric)
Mounting Type: Surface Mount
Operating Temperature Range: -55°C ~ 125°C (minimum)

Allowable Variation Parameters:

Current Rating (Max): May exceed 3A (higher current capability is acceptable)
DC Resistance (DCR) (Max): May be lower than 50mOhm (lower resistance is acceptable)
Height (Max): Minor variations within mechanical assembly constraints
Filter Type: Power Line, Signal Line, or Power/Signal Line combinations are functionally compatible

Compliance Parameters:

RoHS Status: ROHS3 Compliant or RoHS Compliant
Moisture Sensitivity Level: 1 (Unlimited) preferred
REACH Status: REACH Unaffected

Substitute parts are grouped by their relationship to the main part: Direct Manufacturer equivalents share identical electrical specifications, while Parametric Equivalents meet or exceed the core electrical requirements with acceptable variations in current handling or DC resistance.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Impedance @ Frequency	Current Rating (Max)	DC Resistance (Max)	Package / Case	Height (Max)	Operating Temperature	Product Status	RoHS Status
MH4532-121Y	Bourns Inc.	120 Ohms @ 100 MHz	3A	50mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Obsolete	ROHS3 Compliant
742792511	Würth Elektronik	120 Ohms @ 100 MHz	3A	50mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	ROHS3 Compliant
FBU453215T-121Y-S-H	Cal-Chip Electronics, Inc.	120 Ohms @ 100 MHz	6A	15mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	RoHS Compliant
MI1812K121R-10	Laird-Signal Integrity Products	120 Ohms @ 100 MHz	1.5A	55mOhm	1812 (4532 Metric)	0.055" (1.40mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
2518121217Y3	Fair-Rite Products Corp.	120 Ohms @ 100 MHz	3A	40mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	ROHS3 Compliant
BBPY00453215121Y00	Pulse Electronics	120 Ohms @ 100 MHz	4A	30mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	ROHS3 Compliant
BBUP00453215121Y00	Pulse Electronics	120 Ohms @ 100 MHz	6A	20mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	ROHS3 Compliant
FB12YTYH121	Stackpole Electronics Inc	120 Ohms @ 100 MHz	4A	30mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	Not Specified
FBH453215T-121Y-S	Cal-Chip Electronics, Inc.	120 Ohms @ 100 MHz	3A	40mOhm	1812 (4532 Metric)	0.067" (1.70mm)	-55°C ~ 125°C	Active	RoHS Compliant
ILHB1812ER121V	Vishay Dale	120 Ohms @ 100 MHz	6A	20mOhm	1812 (4532 Metric)	0.069" (1.75mm)	-55°C ~ 125°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Recommended Primary Substitute):

742792511 (Würth Elektronik) is the direct equivalent to MH4532-121Y. This part maintains identical electrical specifications (120 Ohms @ 100 MHz, 3A, 50mOhm DCR) and mechanical dimensions. The part is Active status with ROHS3 compliance and unlimited moisture sensitivity rating. This substitution requires no circuit or layout modifications.

Parametric Equivalents with Enhanced Performance:

Parts with current ratings exceeding 3A (FBU453215T-121Y-S-H at 6A, BBPY00453215121Y00 at 4A, BBUP00453215121Y00 at 6A, ILHB1812ER121V at 6A) provide higher current handling capability while maintaining the 120 Ohms @ 100 MHz impedance specification. These parts feature lower DC resistance values, reducing thermal dissipation. All are Active status with appropriate RoHS compliance.

Parametric Equivalents with Matched Current Rating:

2518121217Y3 (Fair-Rite Products Corp.) and FBH453215T-121Y-S (Cal-Chip Electronics, Inc.) maintain the 3A current rating with improved DC resistance (40mOhm versus 50mOhm). Both are Active status with full compliance certifications.

Constrained Substitution:

MI1812K121R-10 (Laird-Signal Integrity Products) has a reduced current rating of 1.5A, making it suitable only for applications where circuit current does not exceed this limit. The operating temperature minimum is -40°C instead of -55°C. This part is not recommended as a general substitute.

Compliance Considerations:

All substitute parts maintain ROHS3 or RoHS compliance. REACH Unaffected status is consistent across all parts. Moisture Sensitivity Level 1 (Unlimited) is standard for all parts except MI1812K121R-10, which lists MSL as Not Applicable.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with higher current rating than the original MH4532-121Y?

A: Yes. Parts rated for 4A or 6A are electrically compatible substitutes. Higher current rating indicates the part can handle greater current without exceeding its thermal limits. The 120 Ohms @ 100 MHz impedance specification remains unchanged. Circuit design current requirements determine the minimum acceptable current rating.

Q: What is the significance of DC Resistance (DCR) variation among substitutes?

A: DC Resistance affects thermal dissipation at operating current. Lower DCR values (15mOhm to 30mOhm) generate less heat than the original 50mOhm specification. This is a beneficial characteristic for thermal management. Higher DCR values (55mOhm) are acceptable if circuit thermal budget permits.

Q: Are all substitute parts mechanically compatible with the original PCB footprint?

A: All listed substitutes use the 1812 (4532 Metric) package with identical length (0.177" / 4.50mm) and width (0.126" / 3.20mm) dimensions. Height variations are minor (0.055" to 0.069") and fall within standard PCB assembly tolerances. ILHB1812ER121V has a maximum height of 0.069" (1.75mm) versus the original 0.067" (1.70mm), a difference of 0.05mm that does not affect assembly or clearance.

Q: Why is the MH4532-121Y listed as Obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. Active substitute parts from other manufacturers provide equivalent or superior electrical performance and are currently available for procurement.

Q: Which substitute offers the best overall compatibility?

A: 742792511 (Würth Elektronik) is the direct equivalent with identical specifications and Active product status. For applications requiring enhanced current handling or lower thermal dissipation, BBUP00453215121Y00 or ILHB1812ER121V provide 6A rating with 20mOhm DCR.

Q: Do substitute parts require different soldering or assembly procedures?

A: No. All substitute parts use identical Surface Mount technology and 1812 package format. Standard reflow soldering procedures for 1812 ferrite beads apply to all listed substitutes.

Q: What is the difference between Power Line and Signal Line filter types among substitutes?

A: Filter type designation indicates the primary application context. Power Line ferrite beads are optimized for power distribution filtering, while Signal Line beads target high-frequency signal integrity. Both types meet the 120 Ohms @ 100 MHz specification and are functionally interchangeable in circuit applications where impedance and current rating are the determining factors.

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