SMBJ51 Equivalent & Substitute Parts

Part Overview

The SMBJ51 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This part operates with a 51V reverse standoff voltage and provides 600W peak pulse power dissipation in a DO-214AA (SMB) package. The SMBJ51 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements.

Substiute Parts

SMBJ51

Littelfuse Inc.In Stock: 875SMBJ51 Datasheet

Current PartRFQ

SMBJ51A

Good-Ark SemiconductorIn Stock: 17410SMBJ51A Datasheet

MFR RecommendedRFQ

SZ1SMB51AT3G

Littelfuse Inc.In Stock: 9177SZ1SMB51AT3G Datasheet

MFR RecommendedRFQ

SMBJ51A

Good-Ark SemiconductorIn Stock: 17410SMBJ51A Datasheet

MFR RecommendedRFQ

SMBJ51A

Good-Ark SemiconductorIn Stock: 17410SMBJ51A Datasheet

MFR RecommendedRFQ

SMBJ51A-13-F

Diodes IncorporatedIn Stock: 15283SMBJ51A-13-F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMBJ51 is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Voltage - Reverse Standoff (Typ): 51V (exact match required)
• Voltage - Clamping (Max) @ Ipp: Must not exceed 86.52V to maintain circuit protection integrity
• Current - Peak Pulse (10/1000µs): 7.3A (exact match required)
• Power - Peak Pulse: 600W (exact match required)
• Type: Zener, Unidirectional (1 channel)

Mechanical Compatibility Criteria:

• Package / Case: DO-214AA, SMB (exact match required)
• Mounting Type: Surface Mount

Compliance Requirements:

• RoHS Status: ROHS3 Compliant
• Moisture Sensitivity Level (MSL): 1 (Unlimited)

All substitute parts listed below meet these criteria and are classified as active products, providing long-term availability and supply chain stability compared to the obsolete SMBJ51.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts are active products with established supply chains, addressing the obsolescence of the SMBJ51. Selection among substitutes should be based on the following factors:

Littelfuse SZ1SMB51AT3G: Maintains the original manufacturer (Littelfuse Inc.) and extends the operating temperature range to -65°C ~ 150°C, matching the SMBJ51 specification. This part carries AEC-Q101 automotive qualification and is suitable for applications requiring automotive-grade reliability. Capacitance specification (345pF @ 1MHz) is provided.

Good-Ark SMBJ51A: Offers the lowest clamping voltage (82.4V) among substitutes, providing improved transient suppression performance. Operating temperature range is -55°C ~ 150°C. This part is available in high volume (17,300 pcs in stock) and is suitable for general-purpose applications where the reduced temperature range is acceptable.

Diodes Incorporated SMBJ51A-13-F: Provides equivalent electrical performance to the Good-Ark SMBJ51A with a clamping voltage of 82.4V and operating temperature range of -55°C ~ 150°C. High inventory availability (15,200 pcs) supports production continuity.

All substitute parts comply with ROHS3 and maintain MSL 1 (Unlimited) moisture sensitivity classification, ensuring compatibility with standard PCB assembly processes.

Frequently Asked Questions (FAQ)

Q: Can the SMBJ51 be directly replaced with any of these substitute parts?

A: Yes. All listed substitute parts maintain the critical electrical parameters (51V reverse standoff, 7.3A peak pulse current, 600W peak power) and identical DO-214AA SMB package specifications. They are pin-compatible and functionally equivalent for circuit protection applications.

Q: What is the difference in clamping voltage between the SMBJ51 and its substitutes?

A: The SMBJ51 has a maximum clamping voltage of 86.52V, while all substitute parts (SMBJ51A variants and SZ1SMB51AT3G) have a maximum clamping voltage of 82.4V. The lower clamping voltage in substitutes provides improved transient suppression performance, reducing voltage stress on protected components.

Q: Are there operating temperature differences I should consider?

A: The SMBJ51 and Littelfuse SZ1SMB51AT3G both operate from -65°C to 150°C. The Good-Ark SMBJ51A and Diodes Incorporated SMBJ51A-13-F operate from -55°C to 150°C. For applications requiring the full -65°C lower temperature limit, the SZ1SMB51AT3G is the appropriate choice.

Q: Does the SZ1SMB51AT3G automotive qualification affect its use in non-automotive applications?

A: No. AEC-Q101 qualification indicates enhanced reliability testing and is suitable for any application. Non-automotive designs can use this part without restriction.

Q: Are all substitute parts available in the same packaging options?

A: All substitute parts are supplied in DO-214AA SMB surface-mount packages. The SMBJ51A (Good-Ark) and SMBJ51A-13-F (Diodes Inc.) are available in Cut Tape (CT) and Tape & Reel (TR) packaging. The SZ1SMB51AT3G is supplied in Tape & Reel (TR) format.

Q: What is the inventory status of these substitute parts?

A: All substitute parts are in active production with substantial inventory: SMBJ51A (Good-Ark) - 17,300 pcs, SZ1SMB51AT3G (Littelfuse) - 9,159 pcs, and SMBJ51A-13-F (Diodes Inc.) - 15,200 pcs. This ensures reliable supply for new designs and production requirements.