MMZ2012R121AT000 Ferrite Bead 120 Ohm 0805 Equivalent & Substitute Parts

Part Overview

The MMZ2012R121AT000 is a 120 Ohm ferrite bead in 0805 (2012 Metric) surface mount package manufactured by TDK Corporation. This single-line signal ferrite bead operates at 120 Ohms impedance at 100 MHz with a maximum current rating of 800mA and DC resistance of 120mOhm. The part is classified as Last Time Buy, indicating limited availability. Equivalent and substitute parts are necessary to ensure design continuity, manage supply chain risk, and accommodate alternative sourcing strategies when the primary part reaches end-of-life status.

Key Parameters

Parameter	Value
Impedance @ Frequency	120 Ohms @ 100 MHz
Current Rating (Max)	800mA
DC Resistance (DCR) (Max)	120mOhm
Package / Case	0805 (2012 Metric)
Number of Lines	1
Operating Temperature	-55°C ~ 125°C
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the MMZ2012R121AT000 is determined by the following critical parameters:

Primary Matching Criteria:

Impedance @ Frequency: 120 Ohms @ 100 MHz (mandatory)
Package / Case: 0805 (2012 Metric) (mandatory for PCB compatibility)
Number of Lines: 1 (mandatory for circuit topology)
Operating Temperature Range: -55°C ~ 125°C (mandatory for thermal compatibility)
Mounting Type: Surface Mount (mandatory for assembly process)

Secondary Compatibility Parameters:

Current Rating (Max): Must equal or exceed 800mA
DC Resistance (DCR) (Max): Must not exceed 120mOhm to maintain electrical performance
RoHS Status: ROHS3 Compliant (regulatory requirement)
Moisture Sensitivity Level (MSL): 1 (Unlimited) preferred for handling compatibility

Substitute parts are grouped into two categories: parametric equivalents (identical electrical and mechanical specifications) and direct substitutes (same impedance and package with acceptable variations in current rating and DCR within design margins).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Impedance @ Frequency	Current Rating (Max)	DC Resistance (DCR) (Max)	Package / Case	Operating Temperature	Product Status
MMZ2012R121AT000	TDK Corporation	120 Ohms @ 100 MHz	800mA	120mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Last Time Buy
MMZ2012Y121BT000	TDK Corporation	120 Ohms @ 100 MHz	800mA	120mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Last Time Buy
BLM21AG121SN1D	Murata Electronics	120 Ohms @ 100 MHz	800mA	100mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Active
BLM21AG121SH1D	Murata Electronics	120 Ohms @ 100 MHz	800mA	100mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Active
MH2029-121Y	Bourns Inc.	120 Ohms @ 100 MHz	2A	100mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Active
2508051217Y6	Fair-Rite Products Corp.	120 Ohms @ 100 MHz	6A	25mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Active
MFBW1V2012-121-R	Eaton - Electronics Division	120 Ohms @ 100 MHz	2A	100mOhm	0805 (2012 Metric)	-40°C ~ 85°C	Active
BLM21RK121SN1D	Murata Electronics	120 Ohms @ 100 MHz	200mA	150mOhm	0805 (2012 Metric)	-55°C ~ 125°C	Active
MMZ1608R121ATA00	TDK Corporation	120 Ohms @ 100 MHz	500mA	180mOhm	0603 (1608 Metric)	-55°C ~ 125°C	Active

Engineering Selection Recommendations

Parametric Equivalents (Direct Replacement):

MMZ2012Y121BT000 (TDK Corporation) provides identical electrical and mechanical specifications to the MMZ2012R121AT000. Both parts maintain 120 Ohms @ 100 MHz impedance, 800mA current rating, and 120mOhm maximum DC resistance in the 0805 package. The primary distinction is product status; MMZ2012Y121BT000 is also Last Time Buy. This part is suitable for direct substitution without design modification.

Active Status Substitutes (Recommended for Long-Term Supply):

BLM21AG121SN1D and BLM21AG121SH1D (Murata Electronics, EMIFIL® series) are Active status parts meeting all critical parameters. Both maintain 120 Ohms @ 100 MHz impedance and 800mA current rating with improved DC resistance of 100mOhm (lower than the 120mOhm maximum). These parts are suitable for direct substitution and provide superior long-term availability.

MH2029-121Y (Bourns Inc.) is an Active status part with 120 Ohms @ 100 MHz impedance and enhanced current rating of 2A with 100mOhm DC resistance. This part accommodates higher current applications and provides extended thermal performance within the -55°C ~ 125°C range.

2508051217Y6 (Fair-Rite Products Corp.) is an Active status part with the highest current rating of 6A and lowest DC resistance of 25mOhm. This part is suitable for applications requiring superior current handling and minimal insertion loss.

Conditional Substitutes:

MFBW1V2012-121-R (Eaton - Electronics Division) meets impedance and package requirements but operates within a reduced temperature range of -40°C ~ 85°C. This part is suitable only for applications not requiring the full -55°C ~ 125°C operating range.

BLM21RK121SN1D (Murata Electronics) has a reduced current rating of 200mA and increased DC resistance of 150mOhm. This part is suitable only for low-current applications where these parameters are acceptable.

Not Recommended:

MMZ1608R121ATA00 (TDK Corporation) uses the 0603 (1608 Metric) package, which is mechanically incompatible with the 0805 footprint. This part requires PCB redesign and is not suitable as a direct substitute.

Frequently Asked Questions (FAQ)

Q: Can MMZ2012Y121BT000 replace MMZ2012R121AT000 without design changes?

A: Yes. MMZ2012Y121BT000 is a parametric equivalent with identical impedance (120 Ohms @ 100 MHz), current rating (800mA), DC resistance (120mOhm), and package (0805). No design modifications are required. Both parts are Last Time Buy status.

Q: What is the difference between BLM21AG121SN1D and BLM21AG121SH1D?

A: Both parts are electrically identical with 120 Ohms @ 100 MHz impedance, 800mA current rating, and 100mOhm DC resistance in 0805 package. The difference is packaging format: BLM21AG121SN1D is supplied in Cut Tape (CT) & Digi-Reel®, while BLM21AG121SH1D is supplied in Tape & Reel (TR). Select based on assembly process requirements.

Q: Why is 2508051217Y6 listed as a substitute if it has different current and DCR specifications?

A: 2508051217Y6 maintains the critical parameters of 120 Ohms @ 100 MHz impedance and 0805 package. The higher current rating (6A) and lower DC resistance (25mOhm) represent performance improvements, not degradation. This part is suitable for applications where the original specifications are met or exceeded.

Q: Can BLM21RK121SN1D be used in place of MMZ2012R121AT000?

A: BLM21RK121SN1D is not recommended as a direct substitute. While it maintains 120 Ohms @ 100 MHz impedance and 0805 package, the reduced current rating (200mA versus 800mA) and increased DC resistance (150mOhm versus 120mOhm maximum) represent performance degradation. Use only if circuit design accommodates these reduced specifications.

Q: Is MMZ1608R121ATA00 compatible with the MMZ2012R121AT000 footprint?

A: No. MMZ1608R121ATA00 uses the 0603 (1608 Metric) package, which is mechanically and electrically incompatible with the 0805 (2012 Metric) footprint. PCB redesign is required for this substitution.

Q: What is the impact of MFBW1V2012-121-R's reduced operating temperature range?

A: MFBW1V2012-121-R operates from -40°C ~ 85°C, compared to the standard -55°C ~ 125°C range. This part is suitable only for applications where the circuit operates within this narrower temperature window. Verify application requirements before selection.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance and Moisture Sensitivity Level 1 (Unlimited), matching the regulatory and handling requirements of the MMZ2012R121AT000.

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