CSFB204-G Equivalent & Substitute Parts Reference

Part Overview

The CSFB204-G is a general-purpose rectifier diode manufactured by Comchip Technology, rated for 400 V DC reverse voltage and 2 A average rectified current in a Surface Mount DO-214AA (SMB) package. This component is classified as Active product status and is RoHS3 compliant. Equivalent and substitute parts are identified based on matching electrical specifications and mechanical compatibility to support design flexibility, supply chain alternatives, and inventory optimization in applications requiring 400 V / 2 A rectification performance.

Key Parameters

Parameter	CSFB204-G Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	2	A
Voltage - Forward (Vf) (Max) @ If	1.25 @ 2 A	V
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	35	ns
Current - Reverse Leakage @ Vr	5 µA @ 400 V	µA
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
Operating Temperature - Junction (Max)	150	°C
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the CSFB204-G are grouped based on the following substitution criteria:

Primary Substitutes (Full Electrical & Mechanical Equivalence): Parts matching all critical parameters: 400 V reverse voltage, 2 A average rectified current, fast recovery speed (≤ 500ns), DO-214AA (SMB) package, and Surface Mount technology. These parts are direct replacements with no derating required.

Secondary Substitutes (Electrical Equivalence with Parameter Variations): Parts meeting the core voltage and current ratings (400 V / 2 A) but with acceptable variations in forward voltage, reverse recovery time, or reverse leakage current within the application tolerance window. These parts maintain functional compatibility in the same package.

Current-Rated Variants (Different Current Ratings): Parts rated at 1 A or 3 A with identical 400 V reverse voltage and DO-214AA (SMB) package. These are applicable in designs where the actual circuit current requirement differs from the nominal 2 A specification, provided the selected part current rating meets or exceeds the application requirement.

Recovery Speed Variants (Standard vs. Fast Recovery): Parts classified as Standard Recovery (> 500ns) versus Fast Recovery (≤ 500ns). Selection depends on circuit switching frequency and EMI requirements; fast recovery types are preferred for high-frequency applications.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [A]	Vf (Max) @ If [V]	Speed	trr [ns]	Ir @ Vr [µA]	Package	Tj (Max) [°C]	RoHS
CSFB204-G	Comchip Technology	400	2	1.25 @ 2 A	Fast Recovery ≤ 500ns	35	5 @ 400 V	DO-214AA (SMB)	150	ROHS3
ES2G-13-F	Diodes Incorporated	400	2	1.25 @ 2 A	Fast Recovery ≤ 500ns	35	5 @ 400 V	DO-214AA (SMB)	150	ROHS3
ES2G-E3/5BT	Vishay General Semiconductor - Diodes Division	400	2	1.1 @ 2 A	Fast Recovery ≤ 500ns	50	10 @ 400 V	DO-214AA (SMB)	150	ROHS3
MURS240-E3/52T	Vishay General Semiconductor - Diodes Division	400	2	1.45 @ 2 A	Fast Recovery ≤ 500ns	75	5 @ 400 V	DO-214AA (SMB)	175	ROHS3
S2G	Diotec Semiconductor	400	2	1.15 @ 2 A	Standard Recovery > 500ns	1500	5 @ 1700 V	DO-214AA (SMB)	150	Not applicable
STTH1R04U	STMicroelectronics	400	1	1.5 @ 1 A	Fast Recovery ≤ 500ns	30	5 @ 400 V	DO-214AA (SMB)	175	ROHS3
STTH1R04UY	STMicroelectronics	400	1	1.6 @ 1 A	Fast Recovery ≤ 500ns	30	5 @ 400 V	DO-214AA (SMB)	175	ROHS3
STTH3R04U	STMicroelectronics	400	3	1.5 @ 3 A	Fast Recovery ≤ 500ns	35	5 @ 400 V	DO-214AA (SMB)	175	ROHS3

Engineering Selection Recommendations

Direct Replacement (Preferred): ES2G-13-F (Diodes Incorporated) is the primary equivalent, matching all electrical parameters and specifications of the CSFB204-G. Both parts are Active status, RoHS3 compliant, and MSL 1 rated. This part is recommended for immediate substitution without circuit re-evaluation.

Electrical Equivalents with Minor Parameter Variations: ES2G-E3/5BT (Vishay) and MURS240-E3/52T (Vishay) maintain 400 V / 2 A ratings and fast recovery characteristics. ES2G-E3/5BT offers lower forward voltage (1.1 V vs. 1.25 V), reducing power dissipation. MURS240-E3/52T supports higher junction temperature (175°C vs. 150°C) and is suitable for thermal-constrained applications. Both are RoHS3 compliant and Active status.

Current-Rated Alternatives: STTH1R04U and STTH1R04UY (STMicroelectronics, 1 A rating) are applicable only in circuits where the actual current requirement does not exceed 1 A. STTH3R04U (STMicroelectronics, 3 A rating) is suitable for applications requiring higher current capacity. All three maintain 400 V reverse voltage, fast recovery speed, RoHS3 compliance, and Active status. STTH1R04UY includes AEC-Q101 automotive qualification.

Recovery Speed Consideration: S2G (Diotec Semiconductor) is a Standard Recovery diode (1.5 µs trr) versus the fast recovery specification of CSFB204-G (35 ns trr). This part is suitable only for low-frequency rectification applications where switching speed is not critical. RoHS status is not applicable for this part.

Compliance & Availability: All recommended primary and secondary substitutes are RoHS3 compliant, MSL 1 rated, and carry Active product status. REACH status is REACH Unaffected for all parts except S2G (Vendor Undefined). All parts are classified under ECCN EAR99 and HTSUS 8541.10.0080.

Frequently Asked Questions (FAQ)

Q: Can ES2G-13-F be used as a direct replacement for CSFB204-G? A: Yes. ES2G-13-F matches all critical electrical parameters: 400 V reverse voltage, 2 A average rectified current, 1.25 V forward voltage at 2 A, 35 ns reverse recovery time, and identical DO-214AA (SMB) package. Both are RoHS3 compliant and MSL 1 rated. No circuit modification is required.

Q: What is the difference between MURS240-E3/52T and CSFB204-G? A: MURS240-E3/52T maintains the same 400 V / 2 A electrical ratings and fast recovery speed. Differences include: higher forward voltage (1.45 V vs. 1.25 V), longer reverse recovery time (75 ns vs. 35 ns), and higher maximum junction temperature (175°C vs. 150°C). This part is suitable for thermal-constrained designs but will generate more heat during conduction.

Q: Can STTH1R04U replace CSFB204-G in a 2 A application? A: No. STTH1R04U is rated for 1 A average rectified current, not 2 A. Using this part in a 2 A circuit will cause the diode to operate beyond its rated current, resulting in excessive heat generation and potential failure. STTH3R04U (3 A rating) is the appropriate current-rated alternative if substitution is necessary.

Q: What is the significance of "Fast Recovery ≤ 500ns" versus "Standard Recovery > 500ns"? A: Fast recovery diodes (≤ 500ns reverse recovery time) are designed for high-frequency switching applications and reduce EMI. Standard recovery diodes (> 500ns) are suitable for low-frequency rectification. S2G is a standard recovery type with 1.5 µs trr and should only be used in low-frequency circuits. CSFB204-G and most substitutes are fast recovery types.

Q: Are STTH1R04U and STTH1R04UY interchangeable? A: Both parts are rated for 400 V / 1 A with identical fast recovery characteristics and DO-214AA (SMB) package. STTH1R04UY includes AEC-Q101 automotive qualification and operates over -40°C to 175°C, while STTH1R04U operates to 175°C maximum. STTH1R04UY is preferred for automotive applications; otherwise, both are functionally equivalent for non-automotive use.

Q: What does MSL 1 (Unlimited) mean for moisture sensitivity? A: MSL 1 indicates the lowest moisture sensitivity level, meaning the component can be stored indefinitely without special moisture control measures. Both CSFB204-G and all recommended substitutes carry MSL 1 rating, eliminating moisture-related handling constraints.

Q: Why is S2G listed as a substitute if it has different recovery characteristics? A: S2G is included as a secondary substitute for applications where switching speed is not critical and cost optimization is prioritized. The 1.5 µs reverse recovery time is acceptable in low-frequency rectification circuits (e.g., power supply input stages operating at 50/60 Hz). For high-frequency switching applications, fast recovery types (CSFB204-G, ES2G-13-F, MURS240-E3/52T) are required.

Q: Can I use STTH3R04U in place of CSFB204-G for thermal margin? A: Yes, with design consideration. STTH3R04U is rated for 3 A (exceeding the 2 A requirement) and supports 175°C junction temperature (vs. 150°C for CSFB204-G). In a 2 A application, this part will operate well below its current rating, reducing thermal stress. Forward voltage is 1.5 V @ 3 A; actual voltage at 2 A will be lower. This substitution provides thermal margin but may increase component cost.

Q: Are all substitute parts RoHS3 compliant? A: All recommended primary and secondary substitutes (ES2G-13-F, ES2G-E3/5BT, MURS240-E3/52T, STTH1R04U, STTH1R04UY, STTH3R04U) are RoHS3 compliant. S2G is listed as "Not applicable" for RoHS status. Verify RoHS compliance requirements for your specific application before selecting S2G.

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