CEFC304-G Equivalent & Substitute Parts Reference

Part Overview

The CEFC304-G is a superfast recovery rectifier diode manufactured by Comchip Technology, rated for 400 V DC reverse voltage with 3 A average rectified current in a surface mount DO-214AB (SMC) package. This component is classified as obsolete product status. Due to its obsolete classification, equivalent substitute parts from active product lines are necessary to maintain design continuity and ensure long-term supply chain reliability for new production runs and ongoing support applications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	1.3 @ 3 A	V
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	50	ns
Current - Reverse Leakage @ Vr	10 µA @ 400 V	µA
Mounting Type	Surface Mount	—
Package / Case	DO-214AB, SMC	—
Operating Temperature - Junction (Max)	150	°C
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution eligibility for the CEFC304-G is determined by strict equivalence across the following critical parameters:

Mandatory Equivalence Criteria:

Voltage - DC Reverse (Vr) (Max): 400 V
Current - Average Rectified (Io): 3 A
Mounting Type: Surface Mount
Package / Case: DO-214AB (SMC)
Speed Classification: Fast Recovery ≤ 500ns, > 200mA (Io)

Acceptable Variation Ranges:

Voltage - Forward (Vf) (Max) @ If: 1.1 V to 1.5 V (within fast recovery classification)
Reverse Recovery Time (trr): 35 ns to 150 ns (fast recovery range)
Current - Reverse Leakage @ Vr: 5 µA to 10 µA @ 400 V
Operating Temperature - Junction: Minimum -65°C to -50°C; Maximum 150°C to 175°C

Substitute parts are grouped into two categories:

Category A - Parametric Equivalents (Comchip Technology): CFRC304-G and CURC304-G maintain identical voltage and current ratings with fast recovery characteristics. These parts are direct functional replacements from the same manufacturer.

Category B - Cross-Manufacturer Equivalents (Active Product Status): ER3G-TP, RS3G-13-F, RS3G-E3/57T, S3G-13-F, STTH3R04S, and UFS340J/TR13 meet all mandatory equivalence criteria and operate within acceptable parameter variation ranges. These parts are sourced from manufacturers with active product status and current RoHS3 compliance certifications.

Category C - Legacy Alternatives (Not For New Designs): S3G-TP is classified as "Not For New Designs" and should be used only for maintenance of existing systems.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) [V]	trr [ns]	Ir @ Vr [µA]	Tj (Max) [°C]	Product Status	RoHS Status
CEFC304-G	Comchip Technology	400	3	1.3 @ 3A	50	10 @ 400V	150	Obsolete	REACH Unaffected
CFRC304-G	Comchip Technology	400	3	1.3 @ 3A	150	5 @ 400V	150	Active	ROHS3 Compliant
CURC304-G	Comchip Technology	400	3	1.3 @ 3A	50	5 @ 400V	150	Active	ROHS3 Compliant
ER3G-TP	Micro Commercial Co	400	3	1.25 @ 3A	35	5 @ 400V	175	Active	ROHS3 Compliant
RS3G-13-F	Diodes Incorporated	400	3	1.3 @ 3A	150	5 @ 400V	150	Active	ROHS3 Compliant
RS3G-E3/57T	Vishay General Semiconductor	400	3	1.3 @ 2.5A	150	10 @ 400V	150	Active	ROHS3 Compliant
S3G	Diotec Semiconductor	400	3	1.15 @ 3A	1500	5 @ 1700V	150	Active	Not applicable
S3G-13-F	Diodes Incorporated	400	3	1.15 @ 3A	Not specified	10 @ 400V	150	Active	ROHS3 Compliant
S3G-TP	Micro Commercial Co	400	3	1.2 @ 3A	Not specified	10 @ 400V	150	Not For New Designs	ROHS3 Compliant
STTH3R04S	STMicroelectronics	400	3	1.5 @ 3A	35	5 @ 400V	175	Active	ROHS3 Compliant
UFS340J/TR13	Microchip Technology	400	3	1.1 @ 3A	50	10 @ 400V	175	Active	RoHS non-compliant

Engineering Selection Recommendations

Primary Substitutes (Recommended for New Designs):

CURC304-G (Comchip Technology) provides the closest functional match to the CEFC304-G, maintaining identical reverse recovery time (50 ns) and forward voltage characteristics while offering active product status and ROHS3 compliance. This part is preferred when design continuity with the original CEFC304-G performance is required.

CFRC304-G (Comchip Technology) is an alternative from the same manufacturer with active status and ROHS3 compliance. The extended reverse recovery time (150 ns) remains within fast recovery classification and is acceptable for applications where switching speed is not critical.

Secondary Substitutes (Cross-Manufacturer Options):

ER3G-TP (Micro Commercial Co) and STTH3R04S (STMicroelectronics) both offer superior reverse recovery time (35 ns) and extended maximum junction temperature (175°C), making them suitable for high-temperature or high-frequency switching applications. Both are ROHS3 compliant and in active production.

RS3G-13-F (Diodes Incorporated) and RS3G-E3/57T (Vishay General Semiconductor) maintain the 150 ns reverse recovery time and are ROHS3 compliant. RS3G-E3/57T matches the original reverse leakage specification (10 µA @ 400 V).

Conditional Substitutes:

S3G-13-F (Diodes Incorporated) and S3G (Diotec Semiconductor) operate with standard recovery characteristics (>500 ns) rather than fast recovery. These parts are suitable only for applications where switching speed requirements are relaxed and lower forward voltage (1.15 V) is beneficial.

S3G-TP (Micro Commercial Co) is classified as "Not For New Designs" and should be used only for field replacement or maintenance of existing systems already using this part number.

UFS340J/TR13 (Microchip Technology) is RoHS non-compliant and should be avoided for new designs subject to RoHS3 requirements.

Compliance Considerations:

All recommended substitutes except UFS340J/TR13 carry ROHS3 compliance certification. All parts maintain REACH Unaffected or REACH Unaffected status. Moisture Sensitivity Level (MSL) is uniformly rated as 1 (Unlimited) across all substitutes, matching the original part.

Frequently Asked Questions (FAQ)

Q: Can CEFC304-G be directly replaced with any of the listed substitutes?

A: Direct replacement is possible only with parts meeting all mandatory equivalence criteria: 400 V reverse voltage, 3 A average rectified current, DO-214AB (SMC) package, and surface mount configuration. All listed substitutes meet these requirements. However, application-specific performance differences exist in reverse recovery time and forward voltage characteristics.

Q: What is the difference between fast recovery and standard recovery diodes in this list?

A: Fast recovery diodes (CEFC304-G, CFRC304-G, CURC304-G, ER3G-TP, RS3G-13-F, RS3G-E3/57T, STTH3R04S, UFS340J/TR13) have reverse recovery time ≤ 500 ns and are suitable for switching power supplies and high-frequency applications. Standard recovery diodes (S3G, S3G-13-F, S3G-TP) have reverse recovery time > 500 ns and are suitable for lower-frequency rectification applications. The CEFC304-G original part is classified as fast recovery with 50 ns trr.

Q: Why is CEFC304-G marked as obsolete?

A: Obsolete status indicates the part is no longer manufactured by Comchip Technology. Equivalent active-status alternatives from the same manufacturer (CFRC304-G, CURC304-G) or cross-manufacturer sources are available to ensure continued supply and design support.

Q: Are all substitutes RoHS3 compliant?

A: No. UFS340J/TR13 is RoHS non-compliant and should not be used in applications requiring RoHS3 certification. All other listed substitutes are ROHS3 compliant. S3G (Diotec Semiconductor) has "Not applicable" RoHS status and should be verified for specific regulatory requirements.

Q: What is the significance of reverse recovery time (trr) differences?

A: Reverse recovery time affects switching speed and electromagnetic interference (EMI) characteristics. The CEFC304-G has 50 ns trr. Substitutes with shorter trr (ER3G-TP and STTH3R04S at 35 ns) provide faster switching with lower EMI. Substitutes with longer trr (CFRC304-G and RS3G variants at 150 ns) are acceptable for applications where switching speed is not performance-critical but may increase EMI.

Q: Can I use S3G or S3G-13-F as direct replacements?

A: S3G and S3G-13-F are standard recovery diodes with 1500 ns and unspecified trr respectively, differing significantly from the CEFC304-G fast recovery classification. These parts are suitable only for low-frequency rectification applications where switching speed is not required. They are not recommended as direct replacements for the original fast recovery CEFC304-G in switching power supply applications.

Q: What does "Not For New Designs" mean for S3G-TP?

A: This status indicates the part is still available for field replacement and maintenance of existing systems but should not be selected for new product designs. Use S3G-13-F or other active-status alternatives for new designs.

Q: Are there temperature rating differences I should consider?

A: Yes. The CEFC304-G has maximum junction temperature of 150°C. ER3G-TP, STTH3R04S, and UFS340J/TR13 offer extended temperature rating to 175°C, making them suitable for high-temperature environments. All other substitutes maintain the 150°C maximum rating.

Q: How do forward voltage differences affect circuit performance?

A: Forward voltage ranges from 1.1 V (UFS340J/TR13) to 1.5 V (STTH3R04S) at 3 A. The CEFC304-G is specified at 1.3 V @ 3 A. Lower forward voltage reduces power dissipation and heat generation; higher forward voltage increases dissipation. For most applications, differences within this range are acceptable, but high-current or thermally constrained designs should verify compatibility.

Q: What packaging options are available?

A: All substitutes are supplied in DO-214AB (SMC) surface mount package. Packaging formats vary: Tape & Reel (TR), Cut Tape (CT) & Digi-Reel®, or unspecified. Verify packaging format compatibility with your procurement and assembly processes.

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