Request Quote
(Ships tomorrow)
Z0805C121CSMST Ferrite Bead 120 Ohm 0805 Equivalent & Substitute Parts
Part Overview
The Z0805C121CSMST is a signal line ferrite bead manufactured by KEMET in the 0805 (2012 Metric) surface mount package. This component provides 120 Ohms impedance at 100 MHz with a maximum current rating of 400mA and 300mOhm DC resistance. 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 Z0805C121CSMST is classified as obsolete. Equivalent and substitute parts are available from multiple manufacturers with identical or superior electrical characteristics, offering continued design support and improved availability for new applications and legacy system replacements.
Substiute Parts
Key Parameters
| Parameter | Value |
|---|---|
| Impedance @ Frequency | 120 Ohms @ 100 MHz |
| Current Rating (Max) | 400mA |
| DC Resistance (DCR) (Max) | 300mOhm |
| Package / Case | 0805 (2012 Metric) |
| Mounting Type | Surface Mount |
| Operating Temperature | -55°C ~ 125°C |
| Number of Lines | 1 |
| Filter Type | Signal Line |
| RoHS Status | ROHS3 Compliant |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) |
Substitute Part Grouping Explanation
Substitution of the Z0805C121CSMST is determined by the following critical parameters:
Mandatory Matching Parameters:
- Impedance @ Frequency: 120 Ohms @ 100 MHz
- Package / Case: 0805 (2012 Metric)
- Mounting Type: Surface Mount
- Number of Lines: 1
- Operating Temperature Range: -55°C ~ 125°C
- RoHS3 Compliance
- MSL 1 (Unlimited)
Allowable Variation Parameters:
- Current Rating (Max): Substitute parts with equal or higher current ratings are acceptable
- DC Resistance (DCR) (Max): Substitute parts with equal or lower DCR values are acceptable
- Filter Type: Signal Line designation is preferred but not mandatory for substitution
- Product Status: Active status parts are preferred over obsolete or Last Time Buy status
Substitute parts are grouped into two categories: direct parametric equivalents with identical impedance and package specifications, and functional equivalents with enhanced electrical performance characteristics.
Parameter Comparison
| Manufacturer Part Number | Manufacturer | Impedance @ 100 MHz | Current Rating (Max) | DCR (Max) | Product Status | Packaging |
|---|---|---|---|---|---|---|
| Z0805C121CSMST | KEMET | 120 Ohms | 400mA | 300mOhm | Obsolete | Cut Tape (CT) |
| Z0805C121ASMST | KEMET | 120 Ohms | 800mA | 150mOhm | Obsolete | Cut Tape (CT) |
| 74279202 | Würth Elektronik | 120 Ohms | 500mA | 100mOhm | Active | Tape & Reel (TR) |
| ACML-0805-121-T | Abracon LLC | 120 Ohms | 800mA | 150mOhm | Active | Tape & Reel (TR) |
| BBGK00201209121Y00 | Pulse Electronics | 120 Ohms | 800mA | 150mOhm | Active | Tape & Reel (TR) |
| BLM21AG121SN1D | Murata Electronics | 120 Ohms | 800mA | 100mOhm | Active | Cut Tape (CT) & Digi-Reel® |
| BLM21BB121SN1D | Murata Electronics | 120 Ohms | 600mA | 190mOhm | Active | Cut Tape (CT) & Digi-Reel® |
| EMI0805R-120 | API Delevan Inc. | 120 Ohms | 500mA | 150mOhm | Active | Tape & Reel (TR) |
| FB201209T-121Y-S-1 | Cal-Chip Electronics, Inc. | 120 Ohms | 800mA | 150mOhm | Active | Tape & Reel (TR) |
| MG2029-101Y | Bourns Inc. | 100 Ohms | 400mA | 200mOhm | Active | Tape & Reel (TR) |
| MMZ2012D121BT000 | TDK Corporation | 120 Ohms | 500mA | 300mOhm | Last Time Buy | Cut Tape (CT) |
Engineering Selection Recommendations
Primary Substitutes (Active Status, Full Compatibility):
The following parts are recommended as primary substitutes due to active product status, full RoHS3 compliance, and electrical performance equal to or exceeding the original specification:
-
BLM21AG121SN1D (Murata Electronics): Provides 800mA current rating with 100mOhm DCR, representing improved performance over the original 400mA/300mOhm specification. Available in high volume with Cut Tape and Digi-Reel packaging options.
-
FB201209T-121Y-S-1 (Cal-Chip Electronics, Inc.): Delivers 800mA current rating with 150mOhm DCR. Active product status with high inventory availability in Tape & Reel packaging.
-
ACML-0805-121-T (Abracon LLC): Offers 800mA current rating with 150mOhm DCR in active production status. Available in Tape & Reel packaging.
-
BBGK00201209121Y00 (Pulse Electronics): Provides 800mA current rating with 150mOhm DCR. Active product status with signal line filter type designation.
Secondary Substitutes (Active Status, Reduced Current Rating):
-
74279202 (Würth Elektronik): Delivers 500mA current rating with 100mOhm DCR, representing improved DCR performance. Active product status suitable for applications with current requirements below 500mA.
-
EMI0805R-120 (API Delevan Inc.): Provides 500mA current rating with 150mOhm DCR. Active product status in Tape & Reel packaging.
Alternative Consideration (Impedance Variation):
- MG2029-101Y (Bourns Inc.): Provides 100 Ohms impedance at 100 MHz with 400mA current rating and 200mOhm DCR. This part is suitable only for applications where 100 Ohm impedance is acceptable as a design alternative to the 120 Ohm specification.
Obsolete/Last Time Buy Status (Not Recommended for New Designs):
- Z0805C121ASMST (KEMET): Obsolete status; use active alternatives instead.
- MMZ2012D121BT000 (TDK Corporation): Last Time Buy status; use active alternatives instead.
Frequently Asked Questions (FAQ)
Q: Can I substitute the Z0805C121CSMST with any 120 Ohm ferrite bead in 0805 package?
A: No. Substitution requires matching the following parameters: 120 Ohms impedance at 100 MHz, 0805 (2012 Metric) package, surface mount mounting type, single signal line configuration, -55°C to 125°C operating temperature range, RoHS3 compliance, and MSL 1 rating. Additional parameters such as current rating and DCR must meet or exceed the original specification.
Q: What is the difference between the Z0805C121CSMST and Z0805C121ASMST?
A: Both parts share identical impedance (120 Ohms @ 100 MHz), package, and operating temperature specifications. The Z0805C121ASMST provides higher current rating (800mA versus 400mA) and lower DC resistance (150mOhm versus 300mOhm). However, both parts are obsolete; active alternatives are recommended.
Q: Is BLM21AG121SN1D a direct replacement for Z0805C121CSMST?
A: BLM21AG121SN1D is a functional equivalent with identical impedance, package, and operating temperature specifications. It provides superior electrical performance with 800mA current rating and 100mOhm DCR compared to the original 400mA/300mOhm specification. The part is in active production status and is suitable for direct substitution.
Q: Why do some substitute parts have different current ratings?
A: Current rating variation reflects different ferrite material compositions and core designs. Substitute parts with equal or higher current ratings are acceptable for the Z0805C121CSMST. Lower current ratings are not acceptable unless the application circuit operates below the reduced current limit.
Q: What is the significance of DC Resistance (DCR) in ferrite bead selection?
A: DCR represents the resistive loss in the ferrite bead at DC and low frequencies. Lower DCR values reduce power dissipation and heat generation in the circuit. Substitute parts with equal or lower DCR values are acceptable. Higher DCR values may increase power loss and are not recommended.
Q: Can I use MG2029-101Y as a substitute?
A: MG2029-101Y has 100 Ohms impedance at 100 MHz, which differs from the original 120 Ohms specification. This part is suitable only if the application circuit design permits 100 Ohm impedance operation. Verification of circuit performance is required before substitution.
Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?
A: Cut Tape packaging provides individual component strips suitable for manual assembly or small-volume production. Tape & Reel packaging provides continuous reels suitable for automated assembly equipment. Both packaging formats contain identical components; selection depends on assembly process requirements.
Q: Are all substitute parts RoHS3 compliant?
A: All recommended substitute parts listed in this document are RoHS3 compliant. Compliance certification is a mandatory requirement for substitution eligibility.
Q: What does MSL 1 (Unlimited) moisture sensitivity rating mean?
A: MSL 1 indicates the component has unlimited shelf life and does not require special moisture control during storage or handling. All substitute parts maintain MSL 1 rating, ensuring compatibility with standard component storage and assembly processes.
Q: Should I prioritize active status parts over obsolete alternatives?
A: Yes. Active status parts ensure continued availability, manufacturing support, and design continuity. Obsolete parts may have limited remaining inventory and no future production. For new designs and legacy system replacements, active status parts are strongly preferred.
Alternative Parts
SJ6012L2TP
Littelfuse Inc.
6 Alternative Parts
JMK107BBJ476MA-RE
Taiyo Yuden
10 Alternative Parts
GMK107BBJ475MA-T
Taiyo Yuden
5 Alternative Parts
SJ6020N2ARP
Littelfuse Inc.
3 Alternative Parts
SJ6025R2ATP
Littelfuse Inc.
4 Alternative Parts
2474-05L
API Delevan Inc.
1 Alternative Parts
4590R-684K
API Delevan Inc.
1 Alternative Parts
CM6560R-334
API Delevan Inc.
1 Alternative Parts
CM6460-104
API Delevan Inc.
1 Alternative Parts
5526-12
API Delevan Inc.
1 Alternative Parts