SRF2012-121Y Equivalent & Substitute Parts

Part Overview

The SRF2012-121Y is a 2-line common mode choke (CMC) manufactured by Bourns Inc., designed for surface mount applications. This component provides 120 Ohms impedance at 100 MHz with a maximum current rating of 370mA and DC resistance of 300mOhm. The part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical performance across impedance, current rating, and DC resistance specifications while accommodating mechanical and thermal constraints.

Key Parameters

Parameter	Value
Manufacturer Part Number	SRF2012-121Y
Manufacturer	Bourns Inc.
Number of Lines	2
Impedance @ Frequency	120 Ohms @ 100 MHz
Current Rating (Max)	370mA
DC Resistance (DCR) (Max)	300mOhm
Voltage Rating - DC	50V
Operating Temperature	-55°C ~ 125°C
Mounting Type	Surface Mount
Package / Case	Horizontal, 4 PC Pad
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the SRF2012-121Y is determined by the following critical parameters:

Impedance @ Frequency: Must equal 120 Ohms @ 100 MHz
Number of Lines: Must equal 2
DC Resistance (DCR): Must not exceed 300mOhm
Current Rating: Must be equal to or greater than 370mA
Voltage Rating - DC: Must be equal to or greater than 50V
Mounting Type: Must be Surface Mount
Package / Case: Must be Horizontal, 4 PC Pad

Both identified substitutes meet these core electrical and mechanical requirements. Variations in operating temperature range and physical dimensions (within the same package class) do not preclude substitution when the primary electrical specifications are satisfied.

Parameter Comparison

Parameter	SRF2012-121Y	SRF2012-121YA	ICM0805ER121M
Manufacturer	Bourns Inc.	Bourns Inc.	Vishay Dale
Number of Lines	2	2	2
Impedance @ Frequency	120 Ohms @ 100 MHz	120 Ohms @ 100 MHz	120 Ohms @ 100 MHz
Current Rating (Max)	370mA	400mA	370mA
DC Resistance (DCR) (Max)	300mOhm	300mOhm	300mOhm
Voltage Rating - DC	50V	50V	50V
Operating Temperature	-55°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	Horizontal, 4 PC Pad	Horizontal, 4 PC Pad	Horizontal, 4 PC Pad
Size / Dimension	0.081" L x 0.049" W (2.05mm x 1.25mm)	0.079" L x 0.047" W (2.00mm x 1.20mm)	0.079" L x 0.047" W (2.00mm x 1.20mm)
Height (Max)	0.057" (1.45mm)	0.055" (1.40mm)	0.057" (1.45mm)
Product Status	Obsolete	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

SRF2012-121YA (Bourns Inc.): This substitute is the primary recommendation for direct replacement. It maintains identical electrical specifications (120 Ohms @ 100 MHz, 300mOhm DCR, 50V DC rating) while offering improved current capacity (400mA vs. 370mA). The part is in active production status, ensuring long-term availability. Operating temperature range is -40°C ~ 125°C, which is narrower at the lower end but sufficient for most industrial applications. Physical dimensions are marginally smaller, and the part is supplied in Tape & Reel packaging. ROHS3 compliance and MSL 1 rating match the original specification.

ICM0805ER121M (Vishay Dale): This substitute meets all core electrical requirements with identical impedance, current rating, and DC resistance specifications. The part is in active production status. Operating temperature range is -40°C ~ 85°C, which is more restrictive at the upper temperature limit. Physical dimensions are equivalent to the SRF2012-121YA. ROHS3 compliance and MSL 1 rating are maintained. This option is suitable for applications where the upper temperature limit of 85°C is acceptable.

Both substitutes are ROHS3 compliant and REACH unaffected, meeting regulatory requirements equivalent to the original part.

Frequently Asked Questions (FAQ)

Q: Can SRF2012-121YA be used as a direct replacement for SRF2012-121Y?

A: Yes. The SRF2012-121YA maintains all critical electrical specifications: 120 Ohms @ 100 MHz impedance, 300mOhm maximum DC resistance, and 50V DC voltage rating. The higher current rating (400mA vs. 370mA) provides additional margin. Physical dimensions are compatible with the same 4-pad horizontal package footprint.

Q: What is the difference between SRF2012-121YA and ICM0805ER121M?

A: Both parts provide identical impedance (120 Ohms @ 100 MHz), DC resistance (300mOhm), and current rating (370mA for ICM0805ER121M). The primary difference is the operating temperature range: SRF2012-121YA operates from -40°C to 125°C, while ICM0805ER121M operates from -40°C to 85°C. Select based on your application's thermal requirements.

Q: Are there packaging differences between these substitutes?

A: The SRF2012-121Y is supplied in standard packaging. SRF2012-121YA is supplied in Tape & Reel (TR) format. ICM0805ER121M is also supplied in Tape & Reel format. Both tape & reel options are compatible with automated assembly processes.

Q: Do all three parts meet RoHS and REACH compliance?

A: Yes. All three parts are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic components.

Q: What is the moisture sensitivity level for these parts?

A: All three parts have MSL 1 (Unlimited), indicating no moisture sensitivity restrictions during storage or handling.

Q: Can ICM0805ER121M be used in high-temperature applications above 85°C?

A: No. ICM0805ER121M is rated for operation only up to 85°C. For applications requiring operation up to 125°C, use SRF2012-121YA.

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