SMBJ51C Equivalent & Substitute Parts

Part Overview

The SMBJ51C is a bidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 51V reverse standoff voltage with an 86.52V maximum clamping voltage and 7.3A peak pulse current capability in a DO-214AA (SMB) package. The SMBJ51C is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Substiute Parts

SMBJ51C

Littelfuse Inc.In Stock: 829SMBJ51C Datasheet

Current PartRFQ

SMBJ51CA

MDDIn Stock: 15751SMBJ51CA Datasheet

DirectRFQ

SMBJ51CA

MDDIn Stock: 15751SMBJ51CA Datasheet

DirectRFQ

SMBJ51CA

MDDIn Stock: 15751SMBJ51CA Datasheet

DirectRFQ

SMBJ51CA

MDDIn Stock: 15751SMBJ51CA Datasheet

DirectRFQ

SMBJ51CA-13-F

Diodes IncorporatedIn Stock: 12327SMBJ51CA-13-F Datasheet

MFR RecommendedRFQ

SMBJ51CAHE3/52

Vishay General Semiconductor - Diodes DivisionIn Stock: 6266SMBJ51CAHE3/52 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMBJ51C is determined by strict equivalence across the following electrical and mechanical parameters:

• Reverse standoff voltage: 51V (typical)
• Peak pulse current: 7.3A (10/1000µs)
• Peak pulse power: 600W
• Package: DO-214AA / SMB surface mount
• Bidirectional configuration: 1 channel
• Zener diode type
• RoHS3 compliance

The substitute parts identified maintain these core specifications. Variations in clamping voltage (82.4V to 86.52V) and operating temperature ranges remain within acceptable tolerance for general-purpose TVS applications. All substitutes are available in the same DO-214AA package footprint, ensuring mechanical and electrical compatibility in existing PCB designs.

Parameter Comparison

Engineering Selection Recommendations

For replacement of the obsolete SMBJ51C, the following prioritization applies:

Primary Recommendation: SMBJ51CA-13-F (Diodes Incorporated)

This part maintains full electrical equivalence with the original SMBJ51C across all critical parameters. Diodes Incorporated maintains active product status with confirmed inventory availability (12,300 units). The part is supplied in Cut Tape and Digi-Reel packaging formats, supporting both prototype and production-volume requirements. ROHS3 compliance and REACH unaffected status confirm regulatory alignment.

Secondary Recommendation: SMBJ51CA (MDD)

The MDD variant provides electrical equivalence with the highest inventory availability (15,680 units). Product status is active with full ROHS3 and REACH compliance. The narrower operating temperature range (-50 to 150°C) is acceptable for most general-purpose applications but should be verified against specific system requirements if operation below -50°C is required.

Tertiary Option: SMBJ51CAHE3/52 (Vishay General Semiconductor)

This Vishay TransZorb® part is qualified to AEC-Q101 automotive standards and carries the automotive-grade designation. Although listed as discontinued at DiGi Electronics, inventory remains available (6,200 units). This option is suitable for automotive or mission-critical applications requiring enhanced qualification documentation. The -55 to 150°C operating range provides extended low-temperature performance.

Frequently Asked Questions (FAQ)

Q: Can SMBJ51CA directly replace SMBJ51C in existing designs?

A: Yes. Both parts share identical reverse standoff voltage (51V), peak pulse current (7.3A), peak pulse power (600W), and DO-214AA package specifications. The clamping voltage difference (82.4V vs. 86.52V) falls within acceptable tolerance for general-purpose TVS applications. PCB layout and footprint compatibility is guaranteed.

Q: What is the difference between SMBJ51CA from MDD and Diodes Incorporated?

A: Both maintain identical electrical specifications (51V standoff, 7.3A peak current, 82.4V clamping). The primary differences are manufacturer, operating temperature range (MDD: -50 to 150°C; Diodes: -55 to 150°C), and packaging options. Diodes Incorporated offers Cut Tape and Digi-Reel formats; MDD availability should be confirmed with the supplier.

Q: Why does SMBJ51CAHE3/52 show "Discontinued at DiGi Electronics" but is still listed as available?

A: Discontinuation status refers to DiGi Electronics's distribution channel only. Vishay continues manufacturing this part, and inventory remains available through authorized distributors. This part is suitable for applications requiring automotive-grade qualification (AEC-Q101).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. SMBJ51CA (MDD), SMBJ51CA-13-F (Diodes Incorporated), and SMBJ51CAHE3/52 (Vishay) are all ROHS3 compliant, matching the original SMBJ51C specification.

Q: What is the impact of the clamping voltage difference (86.52V vs. 82.4V)?

A: The substitute parts clamp at 82.4V maximum, compared to the original 86.52V. This represents a 4.12V reduction in clamping voltage, providing slightly more aggressive overvoltage suppression. For circuits designed around the original 86.52V specification, this difference should be evaluated against the protected component's absolute maximum voltage rating to confirm continued compatibility.

Q: Can I use these parts interchangeably in high-temperature applications?

A: All substitute parts support operation to 150°C junction temperature, matching the original SMBJ51C. However, if operation below -50°C is required, SMBJ51CA-13-F (Diodes) or SMBJ51CAHE3/52 (Vishay) are preferred, as both support -55°C minimum temperature versus MDD's -50°C limit.