SBL840 Equivalent & Substitute Parts

Part Overview

The SBL840 is a Schottky rectifier diode manufactured by Diodes Incorporated, rated for 40 V DC reverse voltage and 8 A average rectified current in a Through Hole TO-220AC package. This component is classified as Obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and procurement continuity. The SBL840 is suitable for applications requiring fast recovery rectification in power supply and switching circuits.

Substiute Parts

SBL840

Diodes IncorporatedIn Stock: 1512SBL840 Datasheet

Current PartRFQ

STPS745D

STMicroelectronicsIn Stock: 17035STPS745D Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SBL840 is determined by the following critical electrical and mechanical parameters:

Voltage Rating Compatibility: The substitute part must have a DC reverse voltage rating equal to or greater than 40 V to ensure safe operation under maximum reverse bias conditions.

Current Rating Compatibility: The substitute part must have an average rectified current rating equal to or greater than 8 A to support the intended load without thermal stress.

Package Compatibility: The substitute part must use the TO-220-2 Through Hole package to ensure mechanical and thermal interface compatibility with existing PCB designs.

Technology Requirement: The substitute part must be a Schottky diode to maintain fast recovery characteristics (≤ 500ns) required for switching applications.

Forward Voltage Consideration: The substitute part's forward voltage drop must be evaluated in the context of the application's power dissipation budget, though higher forward voltage does not preclude substitution if other parameters are met.

The STPS745D from STMicroelectronics meets all substitution criteria for the SBL840.

Parameter Comparison

Engineering Selection Recommendations

The STPS745D is the designated substitute for the SBL840 based on the following engineering criteria:

Regulatory Compliance: Both parts are ROHS3 Compliant, ensuring compatibility with current environmental and regulatory requirements. The STPS745D carries REACH Unaffected status, providing additional regulatory clarity for international applications.

Product Availability: The SBL840 is classified as Obsolete, while the STPS745D is Active with substantial inventory availability (16,973 pieces in stock), ensuring long-term procurement viability and supply chain continuity.

Electrical Performance: The STPS745D provides equivalent or superior electrical characteristics across all critical parameters. The 45 V reverse voltage rating exceeds the 40 V requirement, and the fast recovery speed specification matches the SBL840 exactly. The lower reverse leakage current (100 µA vs. 500 µA) represents an improvement in device performance.

Thermal Performance: The STPS745D supports a maximum junction temperature of 175°C, compared to the SBL840's 150°C maximum, providing enhanced thermal margin in high-temperature operating environments.

Current Rating Consideration: The STPS745D is rated for 7.5 A average rectified current, which is 0.5 A lower than the SBL840's 8 A rating. This difference requires evaluation in applications operating continuously at or near the 8 A level. For applications with typical operating currents below 7.5 A or with intermittent 8 A peaks, the STPS745D is fully suitable.

Frequently Asked Questions (FAQ)

Q: Can the STPS745D directly replace the SBL840 in all applications?

A: The STPS745D is electrically and mechanically compatible with the SBL840 for most applications. The primary consideration is the 0.5 A lower current rating (7.5 A vs. 8 A). Applications operating continuously at 8 A require thermal analysis to confirm the STPS745D can dissipate the resulting power without exceeding its 175°C junction temperature limit.

Q: Are the package dimensions identical between SBL840 and STPS745D?

A: Both parts use the TO-220-2 Through Hole package, ensuring identical PCB footprint and mounting interface. No PCB redesign is required for substitution.

Q: What is the significance of the different forward voltage specifications?

A: The SBL840 specifies 550 mV @ 8 A, while the STPS745D specifies 840 mV @ 15 A. These are measured at different current levels, making direct comparison inappropriate. Forward voltage varies with current and temperature. The STPS745D's specification at 15 A does not indicate higher forward voltage at 8 A operation. Actual forward voltage performance at 8 A operation requires consultation of detailed device datasheets.

Q: Is the STPS745D suitable for high-temperature applications?

A: The STPS745D supports a maximum junction temperature of 175°C, which is 25°C higher than the SBL840. This provides improved thermal headroom for applications in elevated ambient temperature environments or high-power dissipation scenarios.

Q: What is the reverse leakage current difference, and does it matter?

A: The STPS745D exhibits 100 µA reverse leakage at 45 V, compared to the SBL840's 500 µA at 40 V. Lower reverse leakage reduces standby power consumption and improves circuit efficiency, particularly in precision rectification applications.

Q: Are there any compliance or certification differences?

A: Both parts are ROHS3 Compliant. The STPS745D carries REACH Unaffected status, while the SBL840 is REACH Affected. For applications subject to REACH regulations, the STPS745D provides simplified compliance documentation.

Q: Why is the SBL840 obsolete?

A: The SBL840 is classified as Obsolete by the manufacturer. The STPS745D represents the current-generation equivalent from STMicroelectronics, offering improved specifications and active manufacturing support.