SR309 Schottky Diode Equivalent & Substitute Parts

Part Overview

The SR309 is an active Schottky rectifier diode manufactured by Taiwan Semiconductor Corporation, rated for 90V DC reverse voltage and 3A average rectified current in a DO-201AD through-hole axial package. This component is designed for fast recovery applications requiring switching speeds of 500ns or less at currents exceeding 200mA. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity for applications where the SR309 specifications are met by alternative manufacturers' offerings.

Substiute Parts

SR309

Taiwan Semiconductor CorporationIn Stock: 969SR309 Datasheet

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31DQ09

SMC Diode SolutionsIn Stock: 1013131DQ09 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SR309 are identified based on electrical and mechanical parameter compatibility within the Schottky diode rectifier category. The substitution criteria are:

Primary Matching Parameters:

• Voltage - DC Reverse (Vr) (Max): 90V minimum
• Package / Case: DO-201AD, Axial (mechanical compatibility)
• Technology: Schottky (functional equivalence)
• Mounting Type: Through Hole (assembly compatibility)

Secondary Compatibility Parameters:

• Current - Average Rectified (Io): Equal to or greater than 3A
• Voltage - Forward (Vf) (Max) @ If: Equal to or less than 850mV @ 3A
• Speed: Fast Recovery ≤ 500ns, > 200mA (Io)
• Operating Temperature - Junction: Range must encompass or exceed -55°C to 150°C

Parts meeting all primary parameters and secondary electrical specifications are classified as direct substitutes. The 31DQ09 meets these criteria with identical reverse voltage, package configuration, and enhanced current rating.

Parameter Comparison

Engineering Selection Recommendations

The 31DQ09 manufactured by SMC Diode Solutions is a direct substitute for the SR309 in applications requiring 90V Schottky rectifier diodes in DO-201AD through-hole packages. Both components are ROHS3 compliant and carry MSL rating of 1 (Unlimited), ensuring equivalent environmental and regulatory compliance.

The 31DQ09 provides enhanced current capacity (3.3A versus 3A) and identical forward voltage characteristics at the rated current level, making it suitable for designs operating at or near the SR309 current specifications. The operating temperature range of the 31DQ09 (-40°C to 150°C) is narrower than the SR309 (-55°C to 150°C); therefore, applications requiring operation below -40°C junction temperature require the SR309.

Both components are active products with confirmed inventory availability. Selection between these parts should be based on specific application temperature requirements and supply chain considerations.

Frequently Asked Questions (FAQ)

Q: Can the 31DQ09 replace the SR309 in all applications?

A: The 31DQ09 is electrically compatible with the SR309 for applications operating within the temperature range of -40°C to 150°C junction temperature. Applications requiring operation below -40°C must use the SR309 due to its extended lower temperature rating of -55°C.

Q: Are the packages physically identical?

A: Yes. Both the SR309 and 31DQ09 use the DO-201AD axial through-hole package, ensuring identical mechanical compatibility and PCB assembly procedures.

Q: What is the difference in reverse leakage current?

A: The SR309 exhibits 100µA reverse leakage at 90V, while the 31DQ09 exhibits 1mA reverse leakage at 90V. This difference is acceptable for most rectifier applications; however, designs sensitive to leakage current should retain the SR309.

Q: Are both parts RoHS compliant?

A: Yes. Both the SR309 and 31DQ09 are ROHS3 compliant and carry identical MSL ratings of 1 (Unlimited), meeting equivalent environmental and regulatory requirements.

Q: What is the advantage of the 31DQ09's higher current rating?

A: The 31DQ09 is rated for 3.3A average rectified current compared to the SR309's 3A rating. This provides additional design margin in applications operating near the 3A specification limit.

Q: Can these parts be used interchangeably on existing PCBs?

A: Yes. Both components share identical DO-201AD axial package geometry and through-hole mounting specifications, allowing direct substitution without PCB redesign or assembly procedure modification.