BK1608LL121-T Ferrite Bead 120 OHM 0603 Equivalent & Substitute Parts

Part Overview

The BK1608LL121-T is a ferrite bead manufactured by Taiyo Yuden, designed for electromagnetic interference (EMI) suppression in single-line applications. This component provides 120 Ohms of impedance at 100 MHz in a compact 0603 (1608 Metric) surface mount package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility with existing designs.

Key Parameters

Parameter	Value
Impedance @ 100 MHz	120 Ohms
Current Rating (Max)	300 mA
DC Resistance (Max)	500 mOhm
Package / Case	0603 (1608 Metric)
Mounting Type	Surface Mount
Operating Temperature Range	-55°C to 125°C
Number of Lines	1
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the BK1608LL121-T is determined by the following critical parameters:

Primary Matching Criteria:

Impedance at 100 MHz: 120 Ohms (exact match required for primary substitutes)
Package / Case: 0603 (1608 Metric) (mandatory for form factor compatibility)
Number of Lines: 1 (single-line configuration)
Operating Temperature Range: -55°C to 125°C (minimum requirement)
RoHS3 Compliance: Required for regulatory alignment

Secondary Compatibility Factors:

Current Rating: Substitute must equal or exceed 300 mA
DC Resistance: Lower values provide improved performance characteristics
Mounting Type: Surface Mount (fixed requirement)
Product Status: Active status preferred for long-term availability

Substitute parts are categorized into two groups:

Group 1 - Direct Impedance Equivalents (120 Ohms @ 100 MHz): Parts with identical impedance specification, suitable for direct replacement in designs where the original 300 mA current rating is sufficient or where higher current capacity provides design margin.

Group 2 - Parametric Alternatives: Parts with different impedance values (100 Ohms or 140 Ohms) or current ratings outside the primary specification. These are listed for reference in applications where design flexibility permits impedance variation or where higher current handling is required.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Impedance @ 100 MHz	Current Rating (Max)	DC Resistance (Max)	Product Status	Height (Max)
BK1608LL121-T	Taiyo Yuden	120 Ohms	300 mA	500 mOhm	Obsolete	0.037" (0.95 mm)
MH1608-121Y	Bourns Inc.	120 Ohms	2 A	100 mOhm	Active	0.039" (1.00 mm)
2506031217Z0	Fair-Rite Products Corp.	120 Ohms	450 mA	300 mOhm	Active	0.037" (0.95 mm)
74279262	Würth Elektronik	120 Ohms	500 mA	300 mOhm	Active	0.039" (1.00 mm)
ACML-0603-121-T	Abracon LLC	120 Ohms	600 mA	400 mOhm	Active	0.037" (0.95 mm)
BBBK00160808121Y00	Pulse Electronics	120 Ohms	400 mA	250 mOhm	Active	0.037" (0.95 mm)
BBGK00160808121Y00	Pulse Electronics	120 Ohms	600 mA	150 mOhm	Active	0.037" (0.95 mm)
742792620	Würth Elektronik	100 Ohms	500 mA	150 mOhm	Active	0.039" (1.00 mm)
742792621	Würth Elektronik	140 Ohms	550 mA	200 mOhm	Active	0.039" (1.00 mm)
BBBK00160808101Y00	Pulse Electronics	100 Ohms	400 mA	200 mOhm	Active	0.037" (0.95 mm)
BBGK00160808101Y00	Pulse Electronics	100 Ohms	600 mA	150 mOhm	Active	0.037" (0.95 mm)

Engineering Selection Recommendations

Recommended Direct Substitutes (120 Ohms @ 100 MHz):

BBGK00160808121Y00 (Pulse Electronics) - Preferred primary substitute. Provides 600 mA current capacity with 150 mOhm DC resistance, exceeding the original specification. Active product status ensures long-term availability. ROHS3 compliant with MSL 1 rating. Identical 0603 package footprint.
BBBK00160808121Y00 (Pulse Electronics) - Secondary substitute with 400 mA current capacity and 250 mOhm DC resistance. Active status with full compliance certifications. Suitable for applications where the original 300 mA rating is marginal.
MH1608-121Y (Bourns Inc.) - Premium substitute offering 2 A current capacity and 100 mOhm DC resistance. Active product with extensive availability. Height specification of 0.039" (1.00 mm) versus original 0.037" (0.95 mm) requires PCB layout verification for clearance-critical applications.
74279262 (Würth Elektronik) - Active substitute with 500 mA current capacity and 300 mOhm DC resistance. WE-CBF series designation indicates signal line filtering application. Height of 0.039" (1.00 mm) requires clearance verification.
2506031217Z0 (Fair-Rite Products Corp.) - Active substitute with 450 mA current capacity and 300 mOhm DC resistance. Maintains original height specification of 0.037" (0.95 mm). Signal line filter type designation.
ACML-0603-121-T (Abracon LLC) - Active substitute with 600 mA current capacity and 400 mOhm DC resistance. Maintains original height of 0.037" (0.95 mm). REACH unaffected status.

Alternative Impedance Options (for design flexibility only):

742792620 (Würth Elektronik, 100 Ohms @ 100 MHz) - Use only when circuit design permits 20 Ohm impedance reduction
742792621 (Würth Elektronik, 140 Ohms @ 100 MHz) - Use only when circuit design permits 20 Ohm impedance increase

All recommended substitutes maintain ROHS3 compliance, MSL 1 rating, and -55°C to 125°C operating temperature range. Selection should prioritize product status (active), current rating margin above 300 mA, and PCB height clearance requirements.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with higher current rating than the original 300 mA specification?

A: Yes. All recommended substitutes with current ratings of 400 mA or higher are suitable for direct replacement. Higher current capacity provides design margin and does not negatively impact circuit performance in applications designed for 300 mA operation.

Q: What is the significance of DC Resistance (DCR) differences between substitute parts?

A: DC Resistance affects power dissipation and insertion loss. Lower DCR values (100-150 mOhm) result in reduced heat generation and improved signal integrity compared to the original 500 mOhm specification. Selection should consider thermal budget and signal path requirements.

Q: Are there height differences between substitute parts that affect PCB layout?

A: Yes. The original BK1608LL121-T has a maximum height of 0.037" (0.95 mm). Substitutes MH1608-121Y, 74279262, and 742792621 have maximum heights of 0.039" (1.00 mm). Verify PCB clearance for components or connectors mounted above the ferrite bead location. BBGK00160808121Y00, BBBK00160808121Y00, ACML-0603-121-T, and 2506031217Z0 maintain the original 0.037" (0.95 mm) height.

Q: What does "Product Status: Active" mean for component selection?

A: Active status indicates the manufacturer currently produces and supports the component. This ensures long-term availability, consistent quality, and continued technical support. The original BK1608LL121-T is obsolete, making active substitutes necessary for new designs and production continuity.

Q: Can I substitute a 100 Ohm or 140 Ohm ferrite bead for the 120 Ohm original?

A: Substitution with different impedance values (742792620 at 100 Ohms or 742792621 at 140 Ohms) is only permissible if circuit design analysis confirms acceptable performance with the impedance variation. These parts are listed for reference in applications where design flexibility exists. Standard practice requires impedance matching to the original specification.

Q: What is the difference between "Filter Type: Power, Signal Line" and "Filter Type: Signal Line"?

A: Filter type designation indicates the intended application category. Power and signal line types are suitable for both power and signal path filtering. Signal line types are optimized for signal path applications. Both are compatible with the original single-line ferrite bead application.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts listed in this document are ROHS3 compliant, matching the original BK1608LL121-T compliance status. Moisture Sensitivity Level (MSL) is 1 (Unlimited) for all parts, indicating no special moisture handling requirements.

Q: What packaging formats are available for substitute parts?

A: Substitute parts are available in Cut Tape (CT), Digi-Reel, and Tape & Reel (TR) formats. Selection depends on procurement and assembly requirements. All formats are compatible with standard surface mount assembly processes.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message