CT4458-20 RF Attenuator: Equivalent & Substitute Parts

Part Overview

The CT4458-20 is a 20dB RF attenuator manufactured by Cal Test Electronics, designed for in-line SMA connector applications across a frequency range of 0 Hz to 18 GHz. This fixed attenuator operates at 50 Ohms impedance with 2W power handling capability and is housed in an SMA In-Line Module package. The part is currently Active in product status and ROHS3 compliant. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity when the primary part becomes unavailable or when application-specific requirements necessitate alternative manufacturers or specifications.

Key Parameters

Parameter	Value
Manufacturer Part Number	CT4458-20
Manufacturer	Cal Test Electronics
Attenuation Value	20dB
Frequency Range	0 Hz ~ 18 GHz
Impedance	50 Ohms
Power Rating	2W
Package / Case	SMA In-Line Module
Product Status	Active
RoHS Status	ROHS3 Compliant
Packaging Type	Bulk

Substitute Part Grouping Explanation

Substitute parts for the CT4458-20 are classified based on strict adherence to the following critical parameters:

Primary Substitution Criteria:

Attenuation Value: 20dB (exact match required)
Impedance: 50 Ohms (exact match required)
Package / Case: SMA In-Line Module (exact match required)
Product Status: Active (required for current procurement)

Secondary Compatibility Parameters:

Frequency Range: 0 Hz ~ 18 GHz (full-band equivalents) or limited-band alternatives (0 Hz ~ 6 GHz, 0 Hz ~ 4 GHz)
Power Rating: 2W (standard rating for this category)
RoHS Compliance: ROHS3 Compliant preferred; RoHS non-compliant parts listed with qualification notes

Grouping Logic:

Group A (Full-Band Equivalents): Parts matching all primary criteria with 0 Hz ~ 18 GHz frequency range
Group B (Limited-Band Alternatives): Parts matching all primary criteria with reduced frequency range (6 GHz or 4 GHz upper limit)
Group C (Military/Specialized): Parts meeting primary criteria with additional qualifications (MIL-DTL standards)

Parameter Comparison

Manufacturer Part Number	Manufacturer	Attenuation (dB)	Frequency Range (GHz)	Impedance (Ohms)	Power (W)	Package	RoHS Status	Product Status	Inventory (Pcs)
CT4458-20	Cal Test Electronics	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	692
P1AT-SAMF-18G2W-20	P1dB Inc	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	1073
R411820121	Radiall USA, Inc.	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	984
R413820000	Radiall USA, Inc.	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	695
SA18E-20	Fairview Microwave	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	962
SA18H-20	Fairview Microwave	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	665
SF0929-6200-20	Amphenol SV Microwave	20	0 ~ 18	50	2	SMA In-Line Module	ROHS3 Compliant	Active	680
M3933/25-88N	Cinch Connectivity Solutions Midwest Microwave	20	0 ~ 18	50	—	SMA In-Line Module	RoHS non-compliant	Active	792
P1AT-SAMF-6G2W-20	P1dB Inc	20	0 ~ 6	50	2	SMA In-Line Module	ROHS3 Compliant	Active	724
R413820115	Radiall USA, Inc.	20	0 ~ 4	50	2	SMA In-Line Module	ROHS3 Compliant	Active	1175
SA6HA-20	Fairview Microwave	20	0 ~ 6	50	2	SMA In-Line Module	ROHS3 Compliant	Active	1087

Engineering Selection Recommendations

Full-Band Equivalents (0 Hz ~ 18 GHz):

The following parts provide complete parametric equivalence to the CT4458-20 across the full 18 GHz frequency range with identical 20dB attenuation, 50 Ohm impedance, 2W power rating, and SMA In-Line Module packaging:

P1AT-SAMF-18G2W-20 (P1dB Inc): ROHS3 compliant, Active status, 1073 units in stock
R411820121 (Radiall USA, Inc.): ROHS3 compliant, Active status, 984 units in stock
R413820000 (Radiall USA, Inc.): ROHS3 compliant, Active status, 695 units in stock
SA18E-20 (Fairview Microwave): ROHS3 compliant, Active status, 962 units in stock
SA18H-20 (Fairview Microwave): ROHS3 compliant, Active status, 665 units in stock
SF0929-6200-20 (Amphenol SV Microwave): ROHS3 compliant, Active status, 680 units in stock

All full-band equivalents maintain ROHS3 compliance and Active product status, ensuring regulatory alignment and long-term availability.

Limited-Band Alternatives (Reduced Frequency Range):

The following parts meet all primary substitution criteria but operate within restricted frequency ranges. Selection of these alternatives is appropriate only when application requirements do not exceed the specified upper frequency limit:

P1AT-SAMF-6G2W-20 (P1dB Inc): 0 Hz ~ 6 GHz, ROHS3 compliant, Active status, 724 units in stock
SA6HA-20 (Fairview Microwave): 0 Hz ~ 6 GHz, ROHS3 compliant, Active status, 1087 units in stock
R413820115 (Radiall USA, Inc.): 0 Hz ~ 4 GHz, ROHS3 compliant, Active status, 1175 units in stock

Military-Grade Alternative:

M3933/25-88N (Cinch Connectivity Solutions Midwest Microwave): Qualified to MIL-DTL-M3933, Active status, 792 units in stock. Note: This part is RoHS non-compliant and does not specify power rating in available documentation. Selection requires verification of RoHS requirements and power handling specifications for the intended application.

Selection Priority:

For applications requiring full 18 GHz bandwidth with standard commercial compliance: Select from full-band equivalents (P1AT-SAMF-18G2W-20, R411820121, R413820000, SA18E-20, SA18H-20, or SF0929-6200-20)
For applications with frequency requirements not exceeding 6 GHz: Limited-band alternatives (P1AT-SAMF-6G2W-20, SA6HA-20) offer equivalent performance with established inventory
For applications requiring military qualification: M3933/25-88N provides MIL-DTL certification; compliance verification required prior to selection

Frequently Asked Questions (FAQ)

Q1: Can I use a limited-band attenuator (0 Hz ~ 6 GHz or 0 Hz ~ 4 GHz) as a direct substitute for the CT4458-20 (0 Hz ~ 18 GHz)?

A: Limited-band alternatives are direct substitutes only when your application operates entirely within the specified frequency range. If your circuit requires operation above 6 GHz or 4 GHz respectively, limited-band parts will not provide specified attenuation performance. Verify your application's maximum operating frequency before selecting a limited-band alternative.

Q2: What is the difference between the Radiall R411820121 and R413820000 models?

A: Both parts are manufactured by Radiall USA, Inc. and provide identical electrical specifications: 20dB attenuation, 0 Hz ~ 18 GHz frequency range, 50 Ohm impedance, 2W power rating, and SMA In-Line Module packaging. Both are ROHS3 compliant and Active. The primary difference is packaging: R411820121 is supplied in Box packaging (984 units in stock), while R413820000 is supplied in Bulk packaging (695 units in stock). Selection between these parts depends on packaging and inventory requirements.

Q3: Why is the M3933/25-88N listed as a substitute if it is RoHS non-compliant?

A: The M3933/25-88N is included because it meets all primary electrical and mechanical substitution criteria (20dB attenuation, 0 Hz ~ 18 GHz frequency range, 50 Ohm impedance, SMA In-Line Module package, Active status) and carries MIL-DTL-M3933 military qualification. It is listed as an alternative for applications where military-grade certification is required and RoHS compliance is not mandated. Applications subject to RoHS regulations must select from ROHS3-compliant alternatives.

Q4: Are all substitute parts pin-compatible with the CT4458-20?

A: All listed substitute parts use identical SMA In-Line Module connectors (male-female configuration) and are mechanically compatible for direct in-line installation. Electrical performance is equivalent across all full-band alternatives. No adapter or modification is required for mechanical or electrical integration.

Q5: What inventory considerations should I evaluate when selecting a substitute?

A: Current inventory levels vary across manufacturers. P1dB Inc (P1AT-SAMF-18G2W-20) maintains the highest full-band inventory at 1073 units. Radiall USA, Inc. (R413820115) offers the highest inventory for limited-band alternatives at 1175 units. For time-sensitive procurement, verify current stock levels with your supplier, as inventory quantities are subject to change.

Q6: Can I mix different manufacturers' attenuators in the same circuit or system?

A: Yes. All listed substitute parts meet identical electrical specifications (20dB attenuation, 50 Ohm impedance, 2W power rating) and are mechanically compatible. Mixing manufacturers within a single circuit or system does not introduce compatibility issues. However, for consistency in procurement, testing, and documentation, it is standard practice to specify a single manufacturer part number per design unless supply constraints require substitution.

Q7: What compliance certifications should I verify before final part selection?

A: Verify RoHS compliance status against your application requirements. All full-band equivalents and most limited-band alternatives are ROHS3 compliant. The M3933/25-88N is RoHS non-compliant and carries MIL-DTL-M3933 military qualification. Additionally, confirm REACH status: most parts are REACH Unaffected or REACH Affected (Radiall parts). Consult your compliance requirements and supplier documentation for final certification verification.

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