FR804 Equivalent & Substitute Parts

Part Overview

The FR804 is a general-purpose rectifier diode manufactured by Diodes Incorporated, rated for 400 V DC reverse voltage and 8 A average rectified current in a Through Hole TO-220AC package. This component is classified as Obsolete, indicating discontinuation from the original manufacturer. Locating equivalent or substitute parts is necessary to support ongoing system maintenance, repair, and new design implementations where this diode specification remains applicable.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	400	V
Current - Average Rectified (Io)	8	A
Voltage - Forward (Vf) (Max) @ If	1.3	V @ 8 A
Reverse Recovery Time (trr)	150	ns
Current - Reverse Leakage @ Vr	10	µA @ 400 V
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	-
Mounting Type	Through Hole	-
Package / Case	TO-220-2	-
Operating Temperature - Junction	-65 to 175	°C
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitute parts for the FR804 are classified based on strict electrical and mechanical parameter alignment:

Parametric Equivalents maintain identical or near-identical electrical specifications:

Voltage - DC Reverse (Vr): 400 V (exact match required)
Current - Average Rectified (Io): 8 A (exact match required)
Voltage - Forward (Vf) @ If: 1.3 V @ 8 A (exact match required)
Mounting Type: Through Hole (exact match required)
Package / Case: TO-220-2 (exact match required)
Speed Classification: Fast Recovery ≤ 500ns, > 200mA (Io) (exact match required)

Manufacturer Recommended Substitutes provide higher current ratings or improved performance characteristics while maintaining the 400 V voltage specification and Through Hole TO-220AC package form factor. These parts are suitable where the application can accommodate increased current capacity or enhanced reverse recovery performance.

Compliance Considerations: All substitute parts maintain ROHS3 compliance and EAR99 ECCN classification. REACH status varies by manufacturer and must be verified for specific supply chain requirements.

Parameter Comparison

Parameter	FR804 (Diodes Inc.)	MUR840G (onsemi)	VS-8ETU04-M3 (Vishay)	SDUR840 (SMC)	DPG10I400PA (IXYS)	STTH20R04D (STMicroelectronics)
Voltage - DC Reverse (Vr) (Max)	400 V	400 V	400 V	400 V	400 V	400 V
Current - Average Rectified (Io)	8 A	8 A	8 A	-	10 A	20 A
Voltage - Forward (Vf) (Max) @ If	1.3 V @ 8 A	1.3 V @ 8 A	1.3 V @ 8 A	1.3 V @ 8 A	1.32 V @ 10 A	1.7 V @ 20 A
Reverse Recovery Time (trr)	150 ns	60 ns	60 ns	45 ns	45 ns	45 ns
Current - Reverse Leakage @ Vr	10 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V	10 µA @ 400 V	1 µA @ 400 V	20 µA @ 400 V
Speed Classification	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA	Fast Recovery ≤ 500ns, > 200mA
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-220-2	TO-220-2	TO-220-2	TO-220-2	TO-220-2	TO-220-2
Operating Temperature - Junction	-65 to 175 °C	-65 to 175 °C	-65 to 175 °C	-55 to 150 °C	-55 to 175 °C	Max 175 °C
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Parametric Equivalent Selection (Direct Replacement)

MUR840G (onsemi) and VS-8ETU04-M3 (Vishay) are parametric equivalents to the FR804, maintaining identical electrical specifications at 400 V, 8 A, and 1.3 V forward voltage. Both parts are Active status products with ROHS3 compliance. MUR840G offers improved reverse recovery time (60 ns versus 150 ns) and is available in higher inventory quantities (29,301 pieces). VS-8ETU04-M3 similarly provides 60 ns reverse recovery time with substantial inventory availability (18,675 pieces). Both support the full operating temperature range of -65°C to 175°C.

SDUR840 (SMC Diode Solutions) provides electrical compatibility with 400 V rating, 1.3 V forward voltage, and 10 µA reverse leakage. This part exhibits superior reverse recovery time (45 ns) and is Active status with ROHS3 compliance. Operating temperature range is -55°C to 150°C, which is narrower than the original FR804 specification.

Manufacturer Recommended Substitutes (Enhanced Performance)

DPG10I400PA (IXYS) is rated for 10 A average rectified current at 400 V with 1.32 V forward voltage. This part provides 45 ns reverse recovery time and reduced reverse leakage (1 µA @ 400 V). Operating temperature range extends to -55°C to 175°C. This substitute accommodates applications requiring higher current capacity within the same voltage class.

STTH20R04D (STMicroelectronics) is rated for 20 A average rectified current at 400 V. This part provides 45 ns reverse recovery time and is suitable for applications requiring significantly higher current handling. Forward voltage increases to 1.7 V @ 20 A. Operating temperature maximum is 175°C. This substitute is appropriate where the application design permits higher current ratings and can accommodate increased forward voltage drop.

Compliance Verification

All substitute parts maintain ROHS3 compliance and EAR99 ECCN classification. REACH status differs: MUR840G, VS-8ETU04-M3, and DPG10I400PA are REACH Unaffected; SDUR840 and FR804 are REACH Affected; STTH20R04D is REACH Unaffected. Supply chain requirements must determine REACH status applicability.

Frequently Asked Questions (FAQ)

Q: Can MUR840G directly replace FR804 in existing designs?

A: Yes. MUR840G maintains identical electrical specifications: 400 V reverse voltage, 8 A average rectified current, 1.3 V forward voltage @ 8 A, and Through Hole TO-220-2 package. MUR840G is Active status with ROHS3 compliance. Reverse recovery time is improved (60 ns versus 150 ns), which benefits switching performance. Operating temperature range matches the original specification (-65°C to 175°C).

Q: What is the difference between parametric equivalents and manufacturer recommended substitutes?

A: Parametric equivalents (MUR840G, VS-8ETU04-M3, SDUR840) maintain the same electrical ratings as the FR804: 400 V, 8 A, and 1.3 V forward voltage. Manufacturer recommended substitutes (DPG10I400PA, STTH20R04D) provide higher current ratings (10 A and 20 A respectively) while maintaining the 400 V voltage specification. Substitutes are appropriate where the application design accommodates increased current capacity.

Q: Are all substitute parts available in the same package?

A: All substitute parts use Through Hole mounting in TO-220-2 package configuration. Supplier device packages are designated as TO-220AC or TO-220-2, which are mechanically and electrically compatible for Through Hole PCB assembly.

Q: What is the impact of reverse recovery time differences?

A: The FR804 specifies 150 ns reverse recovery time. Substitute parts offer 45 ns to 60 ns reverse recovery times. Faster reverse recovery reduces switching losses and improves efficiency in high-frequency switching applications. This represents an enhancement over the original specification and does not create compatibility issues.

Q: Does forward voltage difference affect circuit design?

A: The FR804 and its parametric equivalents (MUR840G, VS-8ETU04-M3, SDUR840) all specify 1.3 V forward voltage @ 8 A, ensuring circuit behavior consistency. DPG10I400PA specifies 1.32 V @ 10 A, which is negligible difference. STTH20R04D specifies 1.7 V @ 20 A due to higher current rating; this increased forward voltage drop must be evaluated in thermal and efficiency calculations if this substitute is selected.

Q: What are the REACH compliance implications?

A: FR804 is REACH Affected. Substitute parts vary: MUR840G, VS-8ETU04-M3, and DPG10I400PA are REACH Unaffected; SDUR840 is REACH Affected; STTH20R04D is REACH Unaffected. Supply chain and regulatory requirements determine which parts are acceptable for specific applications and regions.

Q: Can STTH20R04D be used in applications designed for 8 A operation?

A: STTH20R04D is rated for 20 A average rectified current and maintains 400 V reverse voltage specification. This part can be used in 8 A applications; however, the higher current rating and increased forward voltage (1.7 V @ 20 A versus 1.3 V @ 8 A) must be evaluated for thermal management and power dissipation impact. The part is oversized for 8 A operation but electrically compatible.

Q: What inventory considerations apply to these substitutes?

A: MUR840G offers the highest inventory availability (29,301 pieces), followed by VS-8ETU04-M3 (18,675 pieces) and SDUR840 (1,935 pieces). DPG10I400PA and STTH20R04D provide 1,171 and 1,447 pieces respectively. Inventory levels support component selection based on supply chain requirements and lead time considerations.

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