STTH8R04FP Equivalent & Substitute Parts

Part Overview

The STTH8R04FP is a general-purpose rectifier diode manufactured by STMicroelectronics, rated for 400 V DC reverse voltage and 8 A average rectified current in a TO-220FPAC through-hole package with isolated tab. This component is classified as obsolete, indicating discontinuation from active production. Identification of equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this rectifier diode.

Substiute Parts

STTH8R04FP

STMicroelectronicsIn Stock: 1981STTH8R04FP Datasheet

Current PartRFQ

STTH8R04D

STMicroelectronicsIn Stock: 1521STTH8R04D Datasheet

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DURF840

Littelfuse Inc.In Stock: 11843DURF840 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the STTH8R04FP are identified based on electrical and mechanical parameter equivalence within the rectifier diode category. The substitution criteria are strictly defined by the following parameters:

Primary Electrical Parameters:

• Voltage - DC Reverse (Vr) (Max): 400 V
• Current - Average Rectified (Io): 8 A
• Speed Classification: Fast Recovery ≤ 500ns, > 200mA (Io)

Secondary Electrical Parameters:

• Voltage - Forward (Vf) (Max) @ If: 1.5 V @ 8 A (maximum allowable)
• Reverse Recovery Time (trr): 50 ns (maximum allowable)
• Current - Reverse Leakage @ Vr: 10 µA @ 400 V (maximum allowable)

Mechanical Parameters:

• Mounting Type: Through Hole
• Package / Case: TO-220-2 configuration with isolated tab capability

Compliance Parameters:

• RoHS Status: ROHS3 Compliant
• Operating Temperature Range: -40°C ~ 175°C (minimum requirement)

Substitute parts must satisfy all primary electrical parameters and maintain compliance with secondary electrical parameters and mechanical requirements. Parts meeting these criteria are functionally interchangeable within the specified application envelope.

Parameter Comparison

Engineering Selection Recommendations

STTH8R04D (STMicroelectronics)

The STTH8R04D is the primary substitute for the obsolete STTH8R04FP. Both components are manufactured by STMicroelectronics and share identical electrical specifications across all primary and secondary parameters. The STTH8R04D maintains active product status, ensuring ongoing availability and supply chain support. This part is ROHS3 compliant and operates within the same temperature range (-40°C ~ 175°C). The primary distinction is the package configuration: STTH8R04D uses TO-220AC (standard tab) versus STTH8R04FP's TO-220FPAC (full pack isolated tab). This packaging difference requires mechanical evaluation for thermal management and isolation requirements in the target application.

DURF840 (Littelfuse Inc.)

The DURF840 is an alternative substitute manufactured by Littelfuse Inc. This component meets all primary electrical parameters and maintains ROHS3 compliance. The DURF840 demonstrates superior electrical performance in forward voltage (1.3 V versus 1.5 V at 8 A) and reverse recovery time (45 ns versus 50 ns), resulting in reduced power dissipation and improved switching characteristics. The DURF840 uses ITO-220AC packaging with full pack isolated tab configuration, matching the mechanical isolation characteristics of the original STTH8R04FP. Operating temperature range is -55°C ~ 150°C, which is narrower at the upper limit (150°C versus 175°C) but extended at the lower limit. Selection of DURF840 is appropriate for applications where thermal performance optimization and extended low-temperature operation are design requirements.

Frequently Asked Questions (FAQ)

Q: Can STTH8R04D directly replace STTH8R04FP in all applications?

A: STTH8R04D is electrically equivalent to STTH8R04FP across all specified parameters. However, the package configuration differs: STTH8R04D uses TO-220AC (standard tab) while STTH8R04FP uses TO-220FPAC (full pack isolated tab). Applications requiring isolated tab thermal management or electrical isolation must evaluate mechanical compatibility with the target PCB layout and mounting structure.

Q: What is the difference between TO-220AC and TO-220FPAC packaging?

A: TO-220AC features a standard tab configuration, while TO-220FPAC provides a full pack isolated tab. The isolated tab in STTH8R04FP allows independent thermal and electrical isolation from the mounting surface. STTH8R04D's standard tab may require additional isolation measures if the application demands electrical separation between the diode case and the heat sink or mounting structure.

Q: Is DURF840 suitable for high-temperature applications?

A: DURF840 operates within -55°C ~ 150°C junction temperature range, which is 25°C lower than STTH8R04FP's maximum of 175°C. Applications requiring sustained operation above 150°C junction temperature must use STTH8R04D or STTH8R04FP. For applications within 150°C maximum junction temperature, DURF840 is suitable and offers improved thermal efficiency due to lower forward voltage drop.

Q: What are the power dissipation implications of selecting DURF840?

A: DURF840 exhibits lower forward voltage (1.3 V versus 1.5 V at 8 A), resulting in reduced power dissipation of approximately 1.6 W per ampere at rated current. This translates to lower heat generation and improved thermal efficiency. Applications with thermal constraints benefit from this characteristic.

Q: Are all three parts RoHS compliant?

A: Yes. STTH8R04FP, STTH8R04D, and DURF840 are all ROHS3 compliant, meeting environmental and regulatory requirements for lead-free manufacturing and restricted substance limitations.

Q: What is the reverse recovery time significance in substitute selection?

A: Reverse recovery time (trr) affects switching speed and electromagnetic interference characteristics. STTH8R04FP and STTH8R04D both specify 50 ns trr, while DURF840 specifies 45 ns. Lower reverse recovery time reduces switching losses and EMI generation. Applications sensitive to switching transients benefit from DURF840's faster recovery characteristic.

Q: Can STTH8R04D and DURF840 be used interchangeably in the same circuit?

A: Both parts meet the primary electrical specifications (400 V, 8 A, fast recovery). However, differences in forward voltage (1.5 V versus 1.3 V), reverse recovery time (50 ns versus 45 ns), and maximum junction temperature (175°C versus 150°C) require circuit-level evaluation. Thermal design, switching frequency, and temperature operating envelope must be assessed to confirm interchangeability for the specific application.