STTH312B Equivalent & Substitute Parts

Part Overview

The STTH312B is a general-purpose fast recovery rectifier diode manufactured by STMicroelectronics, rated for 1200 V DC reverse voltage and 3 A average rectified current in a surface mount DPAK package. This component is classified as obsolete, necessitating identification of active equivalent parts for new designs and ongoing production requirements. The STTH312B remains available in inventory (749 pieces), but its obsolete status requires engineers to evaluate suitable active alternatives that maintain electrical and mechanical compatibility.

Substiute Parts

STTH312B

STMicroelectronicsIn Stock: 779STTH312B Datasheet

Current PartRFQ

STTH512B-TR

STMicroelectronicsIn Stock: 20234STTH512B-TR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STTH312B is determined by the following electrical and mechanical parameters:

Voltage Rating Compatibility: The substitute part must maintain the 1200 V DC reverse voltage rating to ensure safe operation in the same circuit topology.

Package Compatibility: The substitute part must use the identical TO-252-3 DPAK package with 2 leads plus tab (SC-63) to ensure PCB footprint compatibility without layout modifications.

Mounting Type: Surface mount technology must be preserved for manufacturing process continuity.

Reverse Recovery Time: The substitute part must operate within the fast recovery classification (≤500 ns, >200 mA) to maintain switching performance characteristics.

Temperature Rating: The substitute part must support the same maximum junction temperature of 175°C.

Compliance Standards: The substitute part must maintain ROHS3 compliance and REACH unaffected status for regulatory alignment.

The STTH512B-TR qualifies as a substitute based on these criteria. While it features a higher current rating (5 A versus 3 A), this represents an upward-compatible specification that does not compromise circuit operation in applications designed for the 3 A STTH312B.

Parameter Comparison

Engineering Selection Recommendations

For Obsolete Part Replacement: The STTH512B-TR is the designated substitute for the STTH312B. The STTH512B-TR holds active product status, ensuring long-term availability and supply chain continuity. Both parts maintain identical ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements without modification.

Current Rating Consideration: The STTH512B-TR provides a 5 A average rectified current rating compared to the STTH312B's 3 A rating. This higher current capacity is compatible with circuits designed for the lower 3 A specification, as the substitute operates within the same voltage class and package footprint. No circuit redesign is required for this upward-compatible substitution.

Reverse Recovery Performance: The STTH512B-TR exhibits improved reverse recovery time (95 ns versus 115 ns) and reduced reverse leakage current (5 µA versus 10 µA), both favorable characteristics that enhance switching efficiency and reduce standby power dissipation.

Packaging and Manufacturing: Both parts use identical TO-252-3 DPAK surface mount packages, enabling direct PCB footprint compatibility without layout modifications or manufacturing process changes.

Frequently Asked Questions (FAQ)

Q: Can the STTH512B-TR be used as a direct replacement for the STTH312B in existing designs?

A: Yes. The STTH512B-TR maintains identical voltage rating (1200 V), package type (TO-252-3 DPAK), mounting technology (surface mount), and temperature rating (175°C). The higher current rating (5 A) is compatible with applications designed for 3 A operation.

Q: What is the primary reason for substituting the STTH312B?

A: The STTH312B is classified as obsolete. The STTH512B-TR is the active equivalent that provides continued component availability and supply chain reliability.

Q: Are there any compliance differences between the STTH312B and STTH512B-TR?

A: No. Both parts maintain ROHS3 compliance and REACH unaffected status. No compliance modifications are required for substitution.

Q: Does the STTH512B-TR require different PCB footprint or layout considerations?

A: No. Both parts use the identical TO-252-3 DPAK package with 2 leads plus tab (SC-63). PCB footprints are directly compatible without modification.

Q: How do the electrical characteristics compare between these parts?

A: The STTH512B-TR provides improved performance: faster reverse recovery time (95 ns versus 115 ns), lower reverse leakage current (5 µA versus 10 µA), and higher current capacity (5 A versus 3 A). Forward voltage at rated current is slightly higher (2.2 V @ 5 A versus 2 V @ 3 A).

Q: What is the packaging difference between STTH312B and STTH512B-TR?

A: The STTH512B-TR is supplied in Cut Tape (CT) and Digi-Reel packaging, while the STTH312B packaging format is not specified. Both use the same component package (TO-252-3 DPAK). Packaging format does not affect electrical or mechanical compatibility.

Q: Is the STTH512B-TR suitable for high-temperature applications?

A: Yes. The STTH512B-TR supports the same maximum junction temperature of 175°C as the STTH312B, maintaining thermal performance across the full operating range.