FES8GT/45 Equivalent & Substitute Parts

Part Overview

The FES8GT/45 is a general-purpose rectifier diode rated for 400 V DC reverse voltage and 8 A average rectified current in a through-hole TO-220AC package. Manufactured by Vishay General Semiconductor - Diodes Division, this component is classified as obsolete. Due to its obsolete status and limited availability of the original part number, equivalent and substitute diodes from active manufacturers are necessary for new designs, production continuity, and long-term supply chain reliability.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	400 V
Current - Average Rectified (Io)	8 A
Voltage - Forward (Vf) (Max) @ If	1.3 V @ 8 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Reverse Recovery Time (trr)	50 ns
Current - Reverse Leakage @ Vr	10 µA @ 400 V
Mounting Type	Through Hole
Package / Case	TO-220-2
Operating Temperature - Junction	-55°C ~ 150°C
Technology	Standard

Substitute Part Grouping Explanation

Substitution of the FES8GT/45 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 400 V minimum
Current - Average Rectified (Io): 8 A minimum
Mounting Type: Through Hole
Package / Case: TO-220-2 or TO-220AC compatible
Speed: Fast Recovery ≤ 500ns, > 200mA (Io)

Secondary Compatibility Factors:

Reverse Recovery Time (trr): 50 ns or lower
Current - Reverse Leakage @ Vr: 10 µA @ 400 V or lower
Operating Temperature Range: -55°C minimum to 150°C maximum

Substitute parts are grouped into three categories:

Direct Manufacturer Equivalent (FES8GT-E3/45): Identical electrical specifications with active product status and improved RoHS compliance.
Manufacturer Recommended Equivalents (MUR840-BP, MUR840G, STTH8R04D, STTH8R04DI): Parts meeting or exceeding all primary substitution criteria with active status and RoHS3 compliance.
Parametric Equivalents (ER804_T0_00001, HERA805G, SFA806GHC0G): Parts matching all critical electrical parameters with active status and full compliance certifications.

Parts exceeding the 8 A current rating (DPG10I400PA at 10 A, STTH20R04D at 20 A) are included as higher-capacity alternatives suitable for applications with increased current headroom.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf @ If	trr	Ir @ Vr	Tj (Max)	Product Status	RoHS Status
FES8GT/45	Vishay	400 V	8 A	1.3 V @ 8 A	50 ns	10 µA @ 400 V	150°C	Obsolete	Non-compliant
FES8GT-E3/45	Vishay	400 V	8 A	1.3 V @ 8 A	50 ns	10 µA @ 400 V	150°C	Active	ROHS3 Compliant
DPG10I400PA	IXYS	400 V	10 A	1.32 V @ 10 A	45 ns	1 µA @ 400 V	175°C	Active	ROHS3 Compliant
MUR840-BP	Micro Commercial Co	400 V	8 A	1.3 V @ 8 A	50 ns	5 µA @ 400 V	150°C	Active	Not specified
MUR840G	onsemi	400 V	8 A	1.3 V @ 8 A	60 ns	10 µA @ 400 V	175°C	Active	ROHS3 Compliant
STTH8R04D	STMicroelectronics	400 V	8 A	1.5 V @ 8 A	50 ns	10 µA @ 400 V	175°C	Active	ROHS3 Compliant
STTH8R04DI	STMicroelectronics	400 V	8 A	1.5 V @ 8 A	50 ns	10 µA @ 400 V	175°C	Active	ROHS3 Compliant
STTH20R04D	STMicroelectronics	400 V	20 A	1.7 V @ 20 A	45 ns	20 µA @ 400 V	175°C	Active	ROHS3 Compliant
ER804_T0_00001	Panjit International Inc.	400 V	8 A	1.3 V @ 8 A	35 ns	1 µA @ 400 V	150°C	Active	ROHS3 Compliant
HERA805G	Taiwan Semiconductor Corporation	400 V	8 A	1.3 V @ 8 A	50 ns	10 µA @ 400 V	150°C	Active	ROHS3 Compliant
SFA806GHC0G	Taiwan Semiconductor Corporation	400 V	8 A	1.3 V @ 8 A	35 ns	10 µA @ 400 V	150°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Recommended for Obsolescence Mitigation):

FES8GT-E3/45 is the primary recommended substitute. This part maintains identical electrical specifications to the FES8GT/45 while offering active product status and ROHS3 compliance. It is packaged in tube format and provides the most direct functional replacement with no design modifications required.

Tier 2 - Functionally Equivalent (Active Alternatives):

MUR840G, STTH8R04D, and STTH8R04DI are functionally equivalent parts from established manufacturers with active product status and ROHS3 compliance. These parts meet all primary substitution criteria and offer extended operating temperature ranges (up to 175°C maximum junction temperature). MUR840G is available in high inventory (29,301 pcs) and offers the SWITCHMODE™ series designation. STTH8R04DI provides an insulated TO-220AC package variant suitable for applications requiring electrical isolation.

Tier 3 - Parametric Equivalents (Performance-Optimized Alternatives):

ER804_T0_00001, HERA805G, and SFA806GHC0G provide parametric equivalence with identical 400 V / 8 A ratings. ER804_T0_00001 and SFA806GHC0G offer improved reverse recovery time (35 ns versus 50 ns), reducing switching losses. SFA806GHC0G carries AEC-Q101 automotive qualification, suitable for automotive applications. HERA805G provides specified capacitance data (65 pF @ 4V, 1MHz).

Tier 4 - Higher Current Capacity (Design Margin Applications):

DPG10I400PA (10 A) and STTH20R04D (20 A) are suitable for applications requiring increased current headroom. DPG10I400PA offers improved reverse recovery time (45 ns) and lower reverse leakage (1 µA @ 400 V). STTH20R04D provides 20 A capacity with 45 ns reverse recovery time, suitable for high-current rectification stages.

All recommended substitutes maintain through-hole mounting in TO-220-2 or TO-220AC packages, ensuring mechanical compatibility with existing PCB layouts.

Frequently Asked Questions (FAQ)

Q: Can FES8GT-E3/45 be used as a direct drop-in replacement for FES8GT/45?

A: Yes. FES8GT-E3/45 maintains identical electrical specifications (400 V, 8 A, 1.3 V forward voltage, 50 ns reverse recovery time) and identical TO-220AC package. The primary difference is active product status and ROHS3 compliance. No circuit modifications are required.

Q: What is the difference between MUR840G and STTH8R04D?

A: Both parts meet the 400 V / 8 A specification. MUR840G (onsemi SWITCHMODE™ series) has 60 ns reverse recovery time and operates to 175°C. STTH8R04D (STMicroelectronics) has 50 ns reverse recovery time, 1.5 V forward voltage at 8 A, and operates to 175°C. STTH8R04D offers slightly faster switching characteristics. MUR840G has significantly higher inventory availability (29,301 pcs).

Q: Why are DPG10I400PA and STTH20R04D listed as substitutes if they have higher current ratings?

A: Higher current-rated diodes are functionally compatible substitutes for lower current applications. They provide design margin and can reduce thermal stress in the component. However, they are not required for 8 A applications and may introduce unnecessary cost. Use these parts only if circuit design requires increased current capacity or thermal performance.

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

A: Reverse recovery time determines switching speed and affects power dissipation in switching applications. The FES8GT/45 specifies 50 ns. Substitutes with equal or lower trr (ER804_T0_00001 and SFA806GHC0G at 35 ns, DPG10I400PA and STTH20R04D at 45 ns) provide equal or improved performance. Substitutes with higher trr (MUR840G at 60 ns) are acceptable for most applications but may increase switching losses.

Q: Is the insulated variant STTH8R04DI compatible with standard TO-220AC footprints?

A: STTH8R04DI uses an insulated TO-220AC package (TO-220-2 Insulated). While electrically compatible, the insulated package includes a mica or ceramic isolation layer between the die and the metal tab. This requires verification of PCB mounting hardware and thermal interface design. Standard non-insulated variants (STTH8R04D) are recommended unless electrical isolation is specifically required.

Q: What does RoHS3 compliance mean for component selection?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. All recommended active substitutes carry ROHS3 compliance, ensuring compatibility with modern manufacturing standards and regulatory requirements. The original FES8GT/45 is RoHS non-compliant and should not be used in new designs subject to RoHS regulations.

Q: Can SFA806GHC0G be used in automotive applications?

A: Yes. SFA806GHC0G carries AEC-Q101 automotive qualification, indicating it meets automotive industry reliability and quality standards. This part is suitable for automotive rectification circuits. Other substitutes do not carry automotive qualification unless explicitly specified.

Q: What is the difference between tube and bulk packaging?

A: Tube packaging (standard for most substitutes) provides components in plastic tubes for automated pick-and-place assembly. Bulk packaging (MUR840-BP) provides loose components in bulk quantities. Tube packaging is standard for modern manufacturing. Bulk packaging may require manual handling and is less common in contemporary production environments.

Q: Are all substitute parts available in the same TO-220AC package?

A: All substitute parts use TO-220-2 or TO-220AC packages, which are mechanically and electrically compatible. STTH8R04DI is available in an insulated variant (TO-220-2 Insulated, TO-220AC ins) requiring verification of mounting compatibility. Standard non-insulated variants are recommended for direct replacement unless isolation is required.

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