CTX33-1P Equivalent & Substitute Parts Reference

Part Overview

The CTX33-1P is an unshielded 2-coil inductor array manufactured by Eaton - Electronics Division, part of the Econo-Pac™ series. This component provides dual inductance configurations: 129.32 µH when coils are connected in series and 32.33 µH when connected in parallel. The part is currently classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity.

Substiute Parts

CTX33-1P

Eaton - Electronics DivisionIn Stock: 687CTX33-1P Datasheet

Current PartRFQ

CTX33-1P-R

Eaton - Electronics DivisionIn Stock: 5554CTX33-1P-R Datasheet

DirectRFQ

SLF10145T-330M1R6-PF

TDK CorporationIn Stock: 17352SLF10145T-330M1R6-PF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CTX33-1P is determined by the following critical parameters:

Direct Equivalent Criteria:

• Dual-coil inductor array configuration with series and parallel connection options
• Inductance values: 32.33 µH (parallel) and 129.32 µH (series)
• Current ratings: 800 mA (parallel) and 400 mA (series)
• DC resistance specifications: 250 mOhm max (parallel) and 1.001 Ohm max (series)
• Tolerance: ±20%
• Operating temperature range: -40°C to 85°C
• Surface mount nonstandard package with dimensions 11.43 mm x 11.43 mm x 4.19 mm

Similar Component Criteria:

• Single inductor with inductance value of 33 µH (functionally equivalent to parallel configuration)
• Current rating of 1.7 A (exceeds parallel requirement of 800 mA)
• DC resistance of 97.8 mOhm max (lower than parallel specification of 250 mOhm max)
• Operating temperature range: -40°C to 105°C (extended upper limit)
• Surface mount nonstandard package

Substitution logic is based strictly on electrical parameter compatibility and mechanical mounting requirements. The CTX33-1P-R represents a direct equivalent with identical electrical specifications but active product status and improved RoHS compliance. The SLF10145T-330M1R6-PF from TDK Corporation provides functional equivalence for parallel configuration applications with enhanced current handling capability.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Option):

The CTX33-1P-R is the preferred substitute for the obsolete CTX33-1P. This part maintains identical electrical specifications across all parameters: dual-coil configuration with 32.33 µH parallel and 129.32 µH series inductance values, matching current ratings of 800 mA (parallel) and 400 mA (series), and equivalent DC resistance specifications. The CTX33-1P-R is currently in active production status with 5,444 pieces in stock, ensuring supply continuity. The component achieves ROHS3 compliance, addressing regulatory requirements that the original part does not meet. Mechanical compatibility is confirmed through identical package dimensions (11.43 mm x 11.43 mm x 4.19 mm) and surface mount configuration. The primary distinction is packaging format: CTX33-1P-R is supplied in Tape & Reel format, which is standard for production environments.

For Parallel Configuration Applications:

The SLF10145T-330M1R6-PF from TDK Corporation provides functional equivalence when only the parallel configuration (32.33 µH / 33 µH) is required. This component offers enhanced electrical performance with 1.7 A current rating (exceeding the 800 mA parallel requirement) and lower DC resistance of 97.8 mOhm max (compared to 250 mOhm max specification). The extended operating temperature range of -40°C to 105°C provides additional thermal margin. However, this part is classified as "Not For New Designs," indicating limited future availability. The SLF10145T-330M1R6-PF incorporates shielding (versus unshielded design of CTX33-1P), which may affect electromagnetic coupling in specific circuit topologies. Mechanical compatibility requires verification due to different package dimensions (10.10 mm x 10.10 mm x 4.80 mm) and nonstandard package classification.

Compliance Considerations:

Selection between CTX33-1P-R and SLF10145T-330M1R6-PF must account for RoHS compliance requirements. The CTX33-1P-R achieves ROHS3 compliance, making it suitable for applications subject to RoHS Directive 2011/65/EU. The SLF10145T-330M1R6-PF also achieves ROHS3 compliance. Both substitute options provide superior compliance status compared to the original CTX33-1P, which is RoHS non-compliant.

Frequently Asked Questions (FAQ)

Q: Can the CTX33-1P-R be used as a direct replacement for the CTX33-1P?

A: Yes. The CTX33-1P-R is a direct equivalent with identical electrical specifications. All inductance values, current ratings, DC resistance specifications, tolerance, operating temperature range, and mechanical dimensions are equivalent. The primary differences are product status (active versus obsolete) and packaging format (Tape & Reel versus bulk). RoHS compliance is improved in the CTX33-1P-R.

Q: What is the difference between the parallel and series configurations?

A: The CTX33-1P contains two coils that can be connected in different configurations. Parallel connection yields 32.33 µH inductance with 800 mA current rating and 250 mOhm max DC resistance. Series connection yields 129.32 µH inductance with 400 mA current rating and 1.001 Ohm max DC resistance. Both configurations are available in the same physical component.

Q: Can the SLF10145T-330M1R6-PF replace the CTX33-1P in all applications?

A: The SLF10145T-330M1R6-PF provides functional equivalence only for applications using the parallel configuration (32.33 µH). This part is a single inductor with 33 µH inductance and cannot provide the series configuration (129.32 µH) of the original part. Additionally, the SLF10145T-330M1R6-PF is shielded, whereas the CTX33-1P is unshielded, which may affect circuit performance in applications sensitive to electromagnetic coupling. The "Not For New Designs" status indicates limited future availability.

Q: What are the packaging differences between these parts?

A: The CTX33-1P is supplied in bulk packaging. The CTX33-1P-R is supplied in Tape & Reel (TR) format, which is standard for automated assembly processes. The SLF10145T-330M1R6-PF is supplied in Cut Tape (CT) and Digi-Reel® formats. Tape & Reel packaging is preferred for production environments due to compatibility with pick-and-place equipment.

Q: Are there mechanical compatibility concerns when substituting these parts?

A: The CTX33-1P and CTX33-1P-R have identical dimensions (11.43 mm x 11.43 mm x 4.19 mm) and are fully mechanically compatible. The SLF10145T-330M1R6-PF has different dimensions (10.10 mm x 10.10 mm x 4.80 mm). While both are surface mount nonstandard packages, the dimensional differences require verification of PCB layout compatibility, particularly for height clearance and spacing constraints.

Q: What is the significance of the ±20% tolerance specification?

A: The ±20% tolerance indicates the allowable variation in inductance value from the nominal specification. For the CTX33-1P parallel configuration (32.33 µH), actual inductance may range from 25.86 µH to 38.80 µH. For the series configuration (129.32 µH), actual inductance may range from 103.46 µH to 155.18 µH. All substitute parts maintain this same tolerance specification, ensuring equivalent performance distribution.

Q: How does the operating temperature range affect part selection?

A: The CTX33-1P and CTX33-1P-R operate from -40°C to 85°C. The SLF10145T-330M1R6-PF extends this range to -40°C to 105°C, providing 20°C additional upper temperature margin. Selection depends on application thermal requirements. For applications operating near or above 85°C, the SLF10145T-330M1R6-PF offers enhanced thermal performance, provided other electrical and mechanical requirements are satisfied.

Q: What does "Not For New Designs" status mean for the SLF10145T-330M1R6-PF?

A: This designation indicates that TDK Corporation does not recommend this component for new product development. While the part is currently available in inventory (17,300 pieces), future availability is not guaranteed. This status suggests the component may be phased out or have limited production continuity. For new designs, the CTX33-1P-R is the recommended choice due to its active product status.

Q: Are there RoHS compliance implications for part selection?

A: The original CTX33-1P is RoHS non-compliant. Both substitute options (CTX33-1P-R and SLF10145T-330M1R6-PF) achieve ROHS3 compliance. For applications subject to RoHS Directive 2011/65/EU or equivalent regulations, either substitute part is acceptable. The CTX33-1P-R is recommended as the primary choice due to direct electrical equivalence and active production status.