Z0603C680CSMST Ferrite Bead 68 Ohm 0603 Equivalent & Substitute Parts

Part Overview

The Z0603C680CSMST is a 68 Ohm ferrite bead manufactured by KEMET in the 0603 (1608 Metric) surface mount package. This component is designed for single-line signal filtering applications with a maximum current rating of 300mA and DC resistance of 350mOhm. The part operates across the temperature range of -55°C to 125°C and is RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating.

The Z0603C680CSMST is classified as obsolete. Identifying equivalent and substitute ferrite beads is necessary to maintain design continuity and ensure component availability for new production runs and legacy system support.

Key Parameters

Parameter	Value
Impedance @ 100 MHz	68 Ohms
Current Rating (Max)	300mA
DC Resistance (DCR) (Max)	350mOhm
Package / Case	0603 (1608 Metric)
Mounting Type	Surface Mount
Operating Temperature	-55°C ~ 125°C
Number of Lines	1
RoHS Status	RoHS3 Compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Ferrite bead substitution is determined by the following critical parameters:

Package Compatibility: All substitute parts must use the 0603 (1608 Metric) surface mount package to ensure PCB footprint compatibility.

Impedance Range: The Z0603C680CSMST operates at 68 Ohms @ 100 MHz. Substitute parts with impedance values between 56 Ohms and 80 Ohms @ 100 MHz are functionally equivalent for signal line filtering applications, as these values fall within the acceptable tolerance band for ferrite bead performance in typical EMI suppression circuits.

Current Rating: Substitute parts must maintain a current rating of at least 300mA to support the original design specifications. Parts with higher current ratings (400mA, 500mA, or 600mA) provide additional design margin.

DC Resistance: The original part specifies 350mOhm maximum DCR. Substitute parts with lower DCR values (100mOhm, 150mOhm, 250mOhm, or 300mOhm) are acceptable as they reduce insertion loss.

Operating Temperature: All substitute parts must support the -55°C to 125°C operating range.

Compliance & Certifications: All substitute parts must be RoHS3 compliant with MSL 1 rating to meet regulatory and manufacturing requirements.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Impedance @ 100 MHz	Current Rating (Max)	DCR (Max)	Package	Product Status	RoHS Status
Z0603C680CSMST	KEMET	68 Ohms	300mA	350mOhm	0603 (1608 Metric)	Obsolete	RoHS3 Compliant
Z0603C560CSMST	KEMET	56 Ohms	400mA	300mOhm	0603 (1608 Metric)	Obsolete	RoHS3 Compliant
74279267	Würth Elektronik	60 Ohms	500mA	300mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
ACML-0603-600-T	Abracon LLC	60 Ohms	600mA	300mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBBK00160808600Y00	Pulse Electronics	60 Ohms	400mA	100mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBBK00160808800Y00	Pulse Electronics	80 Ohms	400mA	150mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBGK00160808700Y00	Pulse Electronics	70 Ohms	600mA	100mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBGK00160808800Y00	Pulse Electronics	80 Ohms	600mA	100mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBNQ00160808600Y00	Pulse Electronics	60 Ohms	500mA	250mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBNQ00160808750Y00	Pulse Electronics	75 Ohms	500mA	250mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant
BBSJ00160808600Y00	Pulse Electronics	60 Ohms	400mA	100mOhm	0603 (1608 Metric)	Active	RoHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Closest Match):

The BBGK00160808700Y00 (Pulse Electronics, 70 Ohms @ 100 MHz) provides the closest impedance match to the original Z0603C680CSMST at 68 Ohms. This part is active in production, offers improved current handling (600mA vs. 300mA), and features lower DC resistance (100mOhm vs. 350mOhm). All compliance certifications align with the original specification.

Secondary Substitutes (Acceptable Range):

Parts with 60 Ohm impedance (74279267 from Würth Elektronik, ACML-0603-600-T from Abracon LLC, and multiple Pulse Electronics variants) fall within the functional substitution range. The Würth Elektronik 74279267 is particularly suitable as an active production part with 500mA current rating and 300mOhm DCR. Abracon LLC ACML-0603-600-T offers the highest current rating (600mA) among 60 Ohm options.

Alternative Substitutes (Extended Range):

The BBBK00160808800Y00 and BBGK00160808800Y00 (both 80 Ohms @ 100 MHz) represent the upper impedance boundary for substitution. These parts maintain full compliance and offer enhanced current handling capabilities.

Obsolete Part Consideration:

The Z0603C560CSMST (56 Ohms) from KEMET is also obsolete but remains available in inventory. This part is suitable only if lower impedance is acceptable for the application.

All recommended substitutes maintain RoHS3 compliance, MSL 1 rating, and -55°C to 125°C operating temperature specifications.

Frequently Asked Questions (FAQ)

Q: Can I substitute a 60 Ohm ferrite bead for the original 68 Ohm part?

A: Yes. The 60 Ohm impedance falls within the acceptable substitution range for signal line ferrite beads. The impedance difference of 8 Ohms represents approximately 12% variance, which is within typical EMI suppression circuit tolerances. Multiple active production parts are available at this impedance level.

Q: What is the significance of DC Resistance (DCR) in ferrite bead selection?

A: DCR determines insertion loss and power dissipation in the signal path. Lower DCR values reduce signal attenuation and heat generation. Substitute parts with DCR values of 100mOhm to 300mOhm are acceptable; lower values provide improved performance margins.

Q: Are all substitute parts pin-compatible with the original Z0603C680CSMST?

A: Yes. All listed substitute parts use the 0603 (1608 Metric) surface mount package with identical footprint dimensions (0.063" L x 0.031-0.032" W). Direct PCB footprint compatibility is confirmed.

Q: Why do some substitute parts have higher current ratings than the original?

A: Higher current ratings indicate improved thermal performance and design margin. A 600mA-rated ferrite bead operating at 300mA experiences lower temperature rise than a 300mA-rated part at the same current. This provides additional reliability headroom in production designs.

Q: Is the Würth Elektronik 74279267 a direct replacement?

A: The 74279267 is a functional equivalent with 60 Ohms @ 100 MHz impedance, 500mA current rating, and 300mOhm DCR. It is an active production part with full RoHS3 compliance. The primary difference is impedance (60 Ohms vs. 68 Ohms), which is within acceptable substitution parameters for signal line applications.

Q: What is the difference between KEMET Z-SMS series and Pulse Electronics BBGK/BBNQ series?

A: Both are 0603 ferrite beads with identical package dimensions and operating temperature ranges. The primary differences are impedance values, current ratings, and DCR specifications. Pulse Electronics parts offer active production status and generally lower DCR values, providing improved insertion loss characteristics.

Q: Can I use a ferrite bead with lower impedance if my circuit requires higher current handling?

A: Impedance and current rating are independent parameters. A 60 Ohm ferrite bead with 600mA rating can replace a 68 Ohm part with 300mA rating if the circuit design accommodates the impedance difference. Verify that the lower impedance does not compromise EMI suppression performance in your specific application.

Q: Are all substitute parts available in the same packaging format?

A: Most substitute parts are supplied in Tape & Reel (TR) format for automated assembly. The original Z0603C680CSMST is supplied in Cut Tape (CT) format. Tape & Reel packaging is standard for production quantities and offers cost advantages in high-volume manufacturing.

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