SS34FA Schottky Diode Equivalent & Substitute Parts

Part Overview

The SS34FA is a 40V, 3A Schottky rectifier diode manufactured by onsemi in SOD-123FA surface mount packaging. This component is classified as "Not For New Designs," indicating it has been superseded in onsemi's product portfolio. Schottky diodes in this voltage and current class are widely used in power supply circuits, reverse polarity protection, and high-frequency rectification applications. Identifying equivalent and substitute parts is necessary to support existing designs, maintain production continuity, and evaluate alternative sourcing options for applications requiring 40V/3A Schottky rectification capability.

Substiute Parts

SS34FA

onsemiIn Stock: 23210SS34FA Datasheet

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PMEG40T30ERX

Nexperia USA Inc.In Stock: 3912PMEG40T30ERX Datasheet

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SS3040HE_R1_00001

Panjit International Inc.In Stock: 6114SS3040HE_R1_00001 Datasheet

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V3FL45-M3/H

Vishay General Semiconductor - Diodes DivisionIn Stock: 6268V3FL45-M3/H Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SS34FA Schottky diode is determined by the following critical parameters:

Mandatory Matching Criteria:

• Voltage - DC Reverse (Vr) (Max): 40V minimum
• Current - Average Rectified (Io): 3A minimum
• Technology: Schottky
• Mounting Type: Surface Mount
• Grade: Automotive
• Qualification: AEC-Q101
• RoHS Status: ROHS3 Compliant

Acceptable Variation Parameters:

• Voltage - Forward (Vf) (Max) @ If: Substitute parts may exhibit lower forward voltage drop, which is electrically favorable
• Current - Reverse Leakage @ Vr: Substitute parts may exhibit lower reverse leakage, which is electrically favorable
• Package / Case: SOD-123W, SOD-123H, and DO-219AB packages are mechanically compatible with SOD-123FA in surface mount applications, subject to PCB layout verification
• Operating Temperature - Junction: Substitute parts with higher maximum junction temperature ratings provide extended thermal margin
• Capacitance @ Vr, F: Variation is acceptable provided the application does not impose strict capacitance requirements

The three substitute parts listed below meet all mandatory criteria and are qualified for direct substitution in automotive-grade applications.

Parameter Comparison

Engineering Selection Recommendations

PMEG40T30ERX (Nexperia USA Inc.)

The PMEG40T30ERX is the primary substitute for the SS34FA. This part maintains identical voltage and current ratings (40V, 3A) in the same SOD-123W package. It carries active product status, full automotive grade qualification (AEC-Q101), and ROHS3 compliance. The PMEG40T30ERX exhibits superior electrical performance with lower forward voltage drop (460 mV vs. 500 mV) and significantly lower reverse leakage current (28 µA vs. 500 µA). The maximum junction temperature rating of 175°C exceeds the SS34FA specification. This part is recommended as the direct replacement for new production and design transitions.

SS3040HE_R1_00001 (Panjit International Inc.)

The SS3040HE_R1_00001 is a secondary substitute offering identical voltage and current ratings in the SOD-123H package. This part maintains active product status and ROHS3 compliance. The package footprint differs from the SS34FA (SOD-123H vs. SOD-123W), requiring PCB layout verification. Reverse leakage current (160 µA) is lower than the SS34FA. Operating temperature range extends to 150°C maximum. This part is suitable for applications where package compatibility can be accommodated.

V3FL45-M3/H (Vishay General Semiconductor - Diodes Division)

The V3FL45-M3/H is a higher-voltage alternative rated at 45V with 3A current capacity in the DO-219AB package. This part carries active product status and ROHS3 compliance. The elevated voltage rating provides additional design margin for applications operating near the 40V limit. The DO-219AB package footprint differs significantly from SOD-123FA, requiring PCB redesign. Forward voltage drop is higher (580 mV vs. 500 mV), and reverse leakage current is elevated (750 µA vs. 500 µA). This part is applicable only when package substitution is feasible and higher voltage rating is beneficial.

Frequently Asked Questions (FAQ)

Q: Can the PMEG40T30ERX directly replace the SS34FA without PCB modification?

A: The PMEG40T30ERX uses the SOD-123W package, which is mechanically and electrically compatible with the SS34FA SOD-123FA package in surface mount applications. No PCB modification is required. Verify that the PCB footprint accommodates SOD-123W dimensions.

Q: What is the primary advantage of substituting to PMEG40T30ERX?

A: The PMEG40T30ERX provides lower forward voltage drop (460 mV vs. 500 mV at 3A) and significantly lower reverse leakage current (28 µA vs. 500 µA at 40V). These characteristics reduce power dissipation and improve circuit efficiency. The part carries active product status, ensuring long-term availability.

Q: Is the SS3040HE_R1_00001 suitable for automotive applications?

A: The SS3040HE_R1_00001 is manufactured by Panjit International Inc. and carries ROHS3 compliance. However, the provided data does not specify automotive grade or AEC-Q101 qualification for this part. Verification with the manufacturer is required before use in automotive applications.

Q: Why does the V3FL45-M3/H have a higher voltage rating (45V vs. 40V)?

A: The V3FL45-M3/H is rated for 45V maximum reverse voltage, providing 5V additional margin above the SS34FA specification. This higher rating is suitable for applications requiring enhanced voltage headroom. The part is not recommended for direct substitution due to package incompatibility (DO-219AB vs. SOD-123FA) and higher forward voltage drop.

Q: What is the impact of package differences between substitute parts?

A: The SS34FA uses SOD-123FA packaging, while substitutes employ SOD-123W, SOD-123H, or DO-219AB packages. SOD-123W and SOD-123H are compact surface mount packages with similar footprints suitable for direct PCB substitution. The DO-219AB package is significantly larger and requires PCB layout redesign. Verify package dimensions and PCB footprint compatibility before component selection.

Q: Are all substitute parts RoHS3 compliant?

A: All substitute parts listed (PMEG40T30ERX, SS3040HE_R1_00001, and V3FL45-M3/H) carry ROHS3 compliance status. The SS34FA is also ROHS3 compliant. All parts maintain MSL 1 (Unlimited) moisture sensitivity level.

Q: Which substitute part offers the best thermal performance?

A: The PMEG40T30ERX provides the highest maximum junction temperature rating at 175°C, compared to 125°C for the SS34FA. The SS3040HE_R1_00001 and V3FL45-M3/H are rated to 150°C. Higher junction temperature ratings provide extended thermal margin in high-ambient or high-power-dissipation applications.

Q: Can the SS34FA be used in new designs?

A: The SS34FA carries "Not For New Designs" product status, indicating it has been superseded. New designs should utilize active substitute parts such as the PMEG40T30ERX to ensure long-term component availability and manufacturer support.