S4G R7G Equivalent & Substitute Parts

Part Overview

The S4G R7G is a general-purpose rectifier diode manufactured by Taiwan Semiconductor Corporation, rated for 400 V DC reverse voltage and 4 A average rectified current in a surface mount DO-214AB (SMC) package. This part is classified as discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives for ongoing design support and procurement continuity. The diode features fast recovery characteristics with switching speed ≤ 500 ns and is suitable for standard rectification applications requiring moderate current capacity at 400 V operation.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) Maximum	400	V
Current - Average Rectified (Io)	4	A
Voltage - Forward (Vf) Maximum @ If	1.15 V @ 4 A	V
Speed Classification	Fast Recovery ≤ 500 ns	ns
Current - Reverse Leakage @ Vr	10	µA @ 400 V
Mounting Type	Surface Mount	—
Package / Case	DO-214AB, SMC	—
Operating Temperature - Junction	-55 to 150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the S4G R7G is determined by strict alignment of electrical and mechanical parameters. The primary substitution criteria are:

Critical Parameters (Must Match):

Voltage - DC Reverse (Vr) Maximum: 400 V
Package / Case: DO-214AB, SMC (surface mount)
Mounting Type: Surface Mount

Secondary Parameters (Determine Functional Equivalence):

Current - Average Rectified (Io): 4 A (exact match) or higher current rating (acceptable for derating applications)
Voltage - Forward (Vf) Maximum: ≤ 1.15 V @ rated current (ensures thermal and efficiency compatibility)
Speed Classification: Fast Recovery ≤ 500 ns (maintains switching performance)
Operating Temperature Range: Must encompass -55°C to 150°C minimum

Substitute parts are grouped into two categories:

Direct Equivalents (Identical Current Rating): Parts rated for exactly 4 A average rectified current with matching voltage and package specifications.

Functional Alternatives (Higher Current Rating): Parts rated for 5 A or higher current capacity at 400 V, which operate within the S4G R7G electrical envelope and provide design margin. These are suitable for applications where the 4 A requirement can be met by a higher-rated device.

Lower Current Alternatives (Not Recommended for Direct Substitution): Parts rated for 3 A or 1.5 A are listed for reference but do not provide equivalent current capacity and are not suitable as direct replacements in designs requiring 4 A operation.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) V	Io (A)	Vf (Max) @ If	Speed	Package	Temp Range °C	Status
S4G R7G	Taiwan Semiconductor	400	4	1.15 V @ 4 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Discontinued
S4G V7G	Taiwan Semiconductor	400	4	1.15 V @ 4 A	Standard > 500 ns	DO-214AB	-55 to 150	Discontinued
CGRC504-G	Comchip Technology	400	5	1.15 V @ 5 A	Standard > 500 ns	DO-214AB	-55 to 150	Active
CFRC304-G	Comchip Technology	400	3	1.3 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Active
CSFC304-G	Comchip Technology	400	3	1.25 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Active
CURC304-G	Comchip Technology	400	3	1.3 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Active
ER3G-TP	Micro Commercial Co	400	3	1.25 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-50 to 175	Active
ES3G-E3/57T	Vishay General Semiconductor	400	3	1.1 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Active
ES3G-E3/9AT	Vishay General Semiconductor	400	3	1.1 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-55 to 150	Active
MURS340S-E3/52T	Vishay General Semiconductor	400	1.5	1.45 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-65 to 175	Active
MURS340S-E3/5BT	Vishay General Semiconductor	400	1.5	1.45 V @ 3 A	Fast ≤ 500 ns	DO-214AB	-65 to 175	Active

Engineering Selection Recommendations

Primary Substitute (Exact Current Match):

The S4G V7G from Taiwan Semiconductor Corporation is the direct electrical equivalent of the S4G R7G, maintaining identical voltage rating (400 V), current capacity (4 A), forward voltage drop (1.15 V @ 4 A), and package format (DO-214AB). The primary difference is recovery speed classification (standard recovery > 500 ns versus fast recovery ≤ 500 ns in the original part). Both parts are discontinued at DiGi Electronics but remain available in inventory. This substitution is valid for applications where standard recovery speed is acceptable.

Secondary Substitute (Higher Current Rating):

The CGRC504-G from Comchip Technology provides a 5 A current rating at 400 V in the same DO-214AB package, with forward voltage drop of 1.15 V @ 5 A. This part is active and widely available. The higher current rating allows operation within the S4G R7G electrical envelope with design margin. Recovery speed is standard (> 500 ns). This substitution is suitable for designs where the 4 A requirement can be accommodated by a higher-rated device and where standard recovery speed is acceptable.

Alternative Substitutes (Lower Current Rating):

Multiple 3 A alternatives are available from Comchip Technology (CFRC304-G, CSFC304-G, CURC304-G), Micro Commercial Co (ER3G-TP), and Vishay General Semiconductor (ES3G-E3/57T, ES3G-E3/9AT). These parts maintain 400 V voltage rating and DO-214AB packaging with fast recovery characteristics. However, the 3 A current rating is below the S4G R7G specification and is not suitable for direct substitution in applications requiring 4 A operation.

Not Recommended:

The MURS340S series (1.5 A rating) does not provide sufficient current capacity for S4G R7G replacement.

Compliance Verification:

All listed substitute parts maintain ROHS3 compliance, MSL 1 (Unlimited) moisture sensitivity rating, and REACH unaffected status, consistent with the original S4G R7G specifications.

Frequently Asked Questions (FAQ)

Q: Can the S4G V7G directly replace the S4G R7G?

A: Yes. The S4G V7G is electrically equivalent with identical voltage (400 V), current (4 A), forward voltage drop (1.15 V @ 4 A), and package (DO-214AB). The difference is recovery speed classification: S4G V7G operates at standard recovery (> 500 ns) while S4G R7G operates at fast recovery (≤ 500 ns). This substitution is valid for applications where standard recovery speed meets circuit requirements.

Q: Can a 5 A rated diode replace a 4 A rated diode?

A: Yes, in the context of the S4G R7G. The CGRC504-G (5 A, 400 V, DO-214AB) operates within the electrical envelope of the S4G R7G and provides design margin. The higher current rating does not create incompatibility; the circuit will draw only the required 4 A. This substitution is valid for applications where standard recovery speed is acceptable.

Q: Why are 3 A alternatives listed if they cannot replace the S4G R7G?

A: The 3 A alternatives (CFRC304-G, CSFC304-G, CURC304-G, ER3G-TP, ES3G-E3/57T, ES3G-E3/9AT) are provided for reference and for applications where design requirements can be modified to operate at 3 A or lower. These parts share the same voltage rating (400 V) and package format (DO-214AB) but do not provide equivalent current capacity for direct substitution in 4 A designs.

Q: What is the significance of fast recovery versus standard recovery?

A: Recovery speed (trr) determines switching characteristics. Fast recovery (≤ 500 ns) enables faster switching transitions and lower reverse recovery charge, beneficial in high-frequency applications. Standard recovery (> 500 ns) is acceptable in lower-frequency rectification circuits. The S4G R7G specifies fast recovery; substitution with standard recovery parts (such as S4G V7G or CGRC504-G) is valid only if circuit switching frequency and performance requirements permit.

Q: Are all substitute parts available in the same packaging options?

A: All substitute parts listed are available in DO-214AB (SMC) surface mount package, matching the S4G R7G. Packaging options (Cut Tape, Tape & Reel, Digi-Reel) vary by manufacturer and part number. Verify packaging availability with the supplier for procurement requirements.

Q: Do substitute parts meet the same compliance standards as the S4G R7G?

A: Yes. All substitute parts listed maintain ROHS3 compliance, MSL 1 (Unlimited) moisture sensitivity rating, and REACH unaffected status, consistent with the original S4G R7G. Compliance certifications are equivalent across all listed alternatives.

Q: What is the operating temperature range consideration for substitution?

A: The S4G R7G operates from -55°C to 150°C junction temperature. Most substitute parts (S4G V7G, CFRC304-G, CSFC304-G, CURC304-G, ES3G-E3/57T, ES3G-E3/9AT) maintain this range. The ER3G-TP extends to -50°C to 175°C, and MURS340S series extends to -65°C to 175°C. For applications within the -55°C to 150°C range, all listed parts are compatible. For extended temperature applications, verify the substitute part temperature specification.

Q: Can I use MURS340S series as a substitute?

A: No. The MURS340S series (1.5 A rating) does not provide sufficient current capacity for direct substitution in applications requiring 4 A operation. This part is listed for reference only and is not recommended as a replacement for the S4G R7G.

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