42422C-R Equivalent & Substitute Parts

Part Overview

The 42422C-R is a 4.23 µH unshielded toroidal inductor manufactured by Murata Power Solutions Inc., rated for 11.4 A continuous current with a maximum DC resistance of 5.2 mOhm. This component is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design support and procurement continuity. The part operates across an industrial temperature range of -40°C to 125°C and is RoHS compliant with unlimited moisture sensitivity rating.

Key Parameters

Parameter	Value	Unit
Inductance	4.23	µH
Inductance Tolerance	±15%	%
Current Rating	11.4	A
DC Resistance (Max)	5.2	mOhm
Shielding	Unshielded	—
Frequency - Self Resonant	90	MHz
Operating Temperature Range	-40 to 125	°C
Mounting Type	Surface Mount	—
Package Type	Nonstandard Toroidal	—
Size	17.00 × 17.00 × 9.90	mm

Substitute Part Grouping Explanation

Substitution eligibility for the 42422C-R is determined by the following critical parameters:

Inductance Value: Target range 4.2–4.23 µH (within combined tolerance bands)
Current Rating: Minimum 11.4 A to maintain thermal and saturation margins
DC Resistance: Maximum 5.4 mOhm to preserve efficiency characteristics
Mounting Type: Surface mount configuration required
Package Footprint: Nonstandard toroidal form factor with compatible dimensions (approximately 17 mm × 17 mm × 10 mm)
Operating Temperature: Minimum range -30°C to 130°C (covers or exceeds original specification)
Compliance: RoHS and REACH status alignment

The HCTR-442 from API Delevan Inc. meets these substitution criteria with inductance of 4.2 µH, current rating of 12.8 A, and DC resistance of 5.4 mOhm maximum. Physical dimensions are compatible (16.89 × 16.89 × 10.16 mm). The substitute is active in production status, ensuring long-term availability.

Parameter Comparison

Parameter	42422C-R (Murata)	HCTR-442 (API Delevan)	Compatibility Notes
Inductance	4.23 µH	4.2 µH	Within combined tolerance (±15% and ±25%)
Inductance Tolerance	±15%	±25%	Substitute tolerance is wider; verify circuit margin requirements
Current Rating	11.4 A	12.8 A	Substitute exceeds requirement
DC Resistance (Max)	5.2 mOhm	5.4 mOhm	Substitute within acceptable margin
Shielding	Unshielded	Shielded	Shielding reduces EMI; verify circuit EMC requirements
Q @ 100 kHz	Not specified	29	Substitute provides measured Q factor
Frequency - Self Resonant	90 MHz	85 MHz	Slight reduction; acceptable for most applications
Operating Temperature Range	-40 to 125°C	-30 to 130°C	Substitute covers upper range; lower limit is -30°C
Mounting Type	Surface Mount	Surface Mount	Compatible
Package Dimensions	17.00 × 17.00 × 9.90 mm	16.89 × 16.89 × 10.16 mm	Footprint compatible; height within tolerance
RoHS Status	RoHS Compliant	ROHS3 Compliant	Both compliant
REACH Status	REACH Unaffected	REACH Unaffected	Both compliant
Product Status	Obsolete	Active	Substitute ensures procurement continuity

Engineering Selection Recommendations

The HCTR-442 is the qualified substitute for the obsolete 42422C-R based on the following engineering criteria:

Electrical Compatibility: The HCTR-442 delivers inductance within the combined tolerance window of both parts (4.2 µH nominal vs. 4.23 µH nominal). Current rating of 12.8 A exceeds the 11.4 A requirement, providing operational margin. DC resistance of 5.4 mOhm is marginally higher but remains within acceptable limits for power loss calculations.

Mechanical Compatibility: Package footprint dimensions are equivalent within manufacturing tolerances. Surface mount configuration and nonstandard toroidal form factor are identical.

Compliance & Availability: The HCTR-442 holds active product status with ROHS3 and REACH compliance, ensuring long-term supply chain stability. The original 42422C-R is obsolete and no longer manufactured.

Design Considerations: The substitute features shielding, which reduces electromagnetic interference compared to the unshielded original. This is generally beneficial but must be verified against circuit EMC specifications. The operating temperature lower limit is -30°C (versus -40°C for the original); applications requiring operation below -30°C require alternative evaluation.

Frequently Asked Questions (FAQ)

Q: Can the HCTR-442 directly replace the 42422C-R in existing designs?

A: Yes, for applications operating above -30°C. The electrical parameters (inductance, current rating, DC resistance) and mechanical footprint are compatible. The shielded design of the HCTR-442 may improve EMI performance. Verify that your circuit does not require operation below -30°C.

Q: What is the inductance tolerance impact of substitution?

A: The original 42422C-R has ±15% tolerance; the HCTR-442 has ±25% tolerance. Both parts' nominal values (4.23 µH and 4.2 µH) fall within the combined tolerance band. Review your circuit's inductance margin requirements to confirm acceptability of the wider tolerance.

Q: Does the shielding on the HCTR-442 affect circuit performance?

A: Shielding reduces radiated EMI and susceptibility to external magnetic fields. For most applications, this is beneficial. If your circuit design specifically requires an unshielded inductor, shielding may alter coupling characteristics; perform circuit simulation or testing to validate.

Q: Are there any temperature range limitations?

A: The HCTR-442 operates from -30°C to 130°C, compared to the original -40°C to 125°C. If your application requires operation below -30°C, the HCTR-442 is not suitable without additional thermal analysis or derating.

Q: What is the self-resonant frequency difference?

A: The HCTR-442 has a self-resonant frequency of 85 MHz versus 90 MHz for the original. This 5 MHz reduction is negligible for most DC-biased inductor applications but should be verified if the inductor operates near its resonant frequency.

Q: Are both parts RoHS and REACH compliant?

A: Yes. The 42422C-R is RoHS compliant and REACH unaffected. The HCTR-442 is ROHS3 compliant and REACH unaffected. Both meet current regulatory requirements.

Q: Why is the original part obsolete?

A: The 42422C-R is classified as obsolete by Murata Power Solutions Inc., indicating end-of-life status and discontinued manufacturing. The HCTR-442 is an active product from API Delevan Inc., ensuring ongoing availability and support.

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