SMDJ78A-T7 Equivalent & Substitute Parts

Part Overview

The SMDJ78A-T7 is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component operates with a reverse standoff voltage of 78V and provides clamping at 126V maximum, with a peak pulse current rating of 23.8A and peak pulse power of 3000W. The part is RoHS3 compliant, MSL Level 1, and currently in active production status with 885 units in stock.

Equivalent and substitute parts are identified based on matching electrical characteristics (voltage ratings, clamping specifications, and current ratings) and mechanical compatibility (DO-214AB/SMC package format). Substitutes may vary in peak pulse current capacity and power dissipation within acceptable operational ranges for the same voltage class.

Substiute Parts

SMDJ78A-T7

Littelfuse Inc.In Stock: 967SMDJ78A-T7 Datasheet

Current PartRFQ

SMCJ78A

MDDIn Stock: 2809SMCJ78A Datasheet

MFR RecommendedRFQ

SMCJ78A

MDDIn Stock: 2809SMCJ78A Datasheet

MFR RecommendedRFQ

SMCJ78A

MDDIn Stock: 2809SMCJ78A Datasheet

MFR RecommendedRFQ

SMCJ78A-TP

Micro Commercial CoIn Stock: 3241SMCJ78A-TP Datasheet

MFR RecommendedRFQ

SMLJ78A

Bourns Inc.In Stock: 837SMLJ78A Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SMDJ78A-T7 is determined by the following critical parameters:

Voltage Class Match: All substitute parts must maintain the same reverse standoff voltage (78V typical), breakdown voltage minimum (86.7V), and clamping voltage maximum (126V). These parameters define the protection threshold and are non-negotiable for circuit compatibility.

Package Compatibility: All substitutes must use the DO-214AB (SMC) surface-mount package to ensure mechanical and electrical compatibility with existing PCB layouts and soldering processes.

Current and Power Rating Tolerance: Substitute parts may have different peak pulse current (Ipp) and peak pulse power ratings. The SMDJ78A-T7 specifies 23.8A and 3000W; substitutes with lower ratings (11.9A, 1500W) remain functionally equivalent for applications where the transient energy does not exceed the substitute's dissipation capability. Substitutes with comparable or higher ratings provide equivalent or enhanced performance.

Compliance and Status: All identified substitutes maintain RoHS3 compliance, MSL Level 1 rating, and active product status, ensuring long-term availability and regulatory alignment.

Parameter Comparison

Engineering Selection Recommendations

SMCJ78A (MDD): This substitute maintains full voltage specification alignment with the SMDJ78A-T7. The reduced peak pulse current (11.9A) and power rating (1500W) make this option suitable for applications where transient energy levels are lower or where cost optimization is prioritized. All compliance certifications (RoHS3, MSL 1) are maintained. Inventory availability is high (2703 units).

SMCJ78A-TP (Micro Commercial Co): This variant provides the same voltage protection characteristics as the main part with identical peak pulse specifications (11.9A, 1500W). The extended operating temperature range (-55°C ~ 175°C) offers enhanced thermal performance compared to the main part. RoHS3 and MSL 1 compliance are confirmed. Stock availability is excellent (3230 units).

SMLJ78A (Bourns Inc.): This substitute delivers near-equivalent performance to the SMDJ78A-T7, with peak pulse current of 22.8A and power rating of 3000W, closely matching the main part's specifications. The operating temperature range (-55°C ~ 150°C) is slightly narrower at the lower end compared to the main part. RoHS3 compliance is maintained; however, REACH status is listed as affected. Inventory is available (732 units).

All substitutes are qualified for direct replacement based on voltage class, package format, and compliance status. Selection should be based on application-specific transient energy requirements and thermal operating conditions.

Frequently Asked Questions (FAQ)

Q: Can SMCJ78A (11.9A rating) replace SMDJ78A-T7 (23.8A rating) in all applications?

A: SMCJ78A is functionally equivalent for applications where the peak transient current does not exceed 11.9A and energy dissipation remains within 1500W. For circuits requiring the full 23.8A or 3000W capability, SMLJ78A is the appropriate substitute. Verify transient pulse specifications in your circuit design before selection.

Q: Are all substitute parts in the same DO-214AB package?

A: Yes. SMCJ78A, SMCJ78A-TP, and SMLJ78A all use the DO-214AB (SMC) surface-mount package, ensuring mechanical and electrical compatibility with existing PCB layouts designed for the SMDJ78A-T7.

Q: What is the difference between SMCJ78A and SMCJ78A-TP?

A: Both parts maintain identical voltage and current specifications (78V standoff, 126V clamp, 11.9A peak pulse). SMCJ78A-TP offers an extended operating temperature range (-55°C ~ 175°C) compared to SMCJ78A (-50°C ~ 150°C), providing enhanced thermal performance in high-temperature environments.

Q: Do all substitutes meet RoHS3 compliance?

A: Yes. SMCJ78A, SMCJ78A-TP, and SMLJ78A are all RoHS3 compliant. SMLJ78A carries REACH affected status; verify REACH compliance requirements for your specific application and region.

Q: Which substitute offers the closest performance match to SMDJ78A-T7?

A: SMLJ78A provides the closest electrical performance match, with peak pulse current of 22.8A and power rating of 3000W, nearly identical to the main part's 23.8A and 3000W specifications. Both maintain the same voltage class and package format.

Q: Is MSL Level 1 maintained across all substitutes?

A: Yes. All identified substitutes (SMCJ78A, SMCJ78A-TP, SMLJ78A) carry MSL Level 1 (Unlimited) moisture sensitivity rating, matching the main part's specification.