1SMC40AT3 Transient Voltage Suppressor - Equivalent & Substitute Parts

Part Overview

The 1SMC40AT3 is a unidirectional transient voltage suppressor (TVS) diode manufactured by onsemi, rated for 1500W peak pulse power at 40V reverse standoff voltage in SMC (DO-214AB) surface mount packaging. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The part is RoHS non-compliant and carries unlimited moisture sensitivity level (MSL 1), suitable for general-purpose transient protection applications.

Substiute Parts

1SMC40AT3

onsemiIn Stock: 8641SMC40AT3 Datasheet

Current PartRFQ

SMCJ40A

MeritekIn Stock: 16042SMCJ40A Datasheet

DirectRFQ

SMCJ40A

MeritekIn Stock: 16042SMCJ40A Datasheet

DirectRFQ

SMCJ40A-13-F

Diodes IncorporatedIn Stock: 1634SMCJ40A-13-F Datasheet

SimilarRFQ

SMCJ40A-TR

STMicroelectronicsIn Stock: 1412SMCJ40A-TR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 1SMC40AT3 is determined by the following critical parameters:

• Voltage - Reverse Standoff (Typ): Must be 40V to maintain circuit protection threshold
• Power - Peak Pulse: Must be 1500W to handle transient energy without degradation
• Package / Case: Must be DO-214AB (SMC) for mechanical and thermal compatibility
• Mounting Type: Must be Surface Mount for PCB assembly compatibility
• Unidirectional Configuration: Single channel zener diode topology

All substitute parts listed below meet these core electrical and mechanical requirements. Variations in clamping voltage and peak pulse current are acceptable within the same power rating and standoff voltage class, as these parameters are determined by the specific diode design while maintaining the same protection envelope.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: SMCJ40A (Meritek)

The SMCJ40A from Meritek is the direct functional equivalent. It maintains identical reverse standoff voltage (40V), peak pulse power (1500W), and SMC package specifications. The part is currently in active production status with ROHS3 compliance, addressing the obsolescence of the original 1SMC40AT3. Inventory availability is substantial (16,019 pcs), supporting both prototype and production requirements.

Alternative Substitute: SMCJ40A-13-F (Diodes Incorporated)

The SMCJ40A-13-F from Diodes Incorporated provides equivalent electrical performance with ROHS3 compliance and active product status. Clamping voltage and peak pulse current specifications are nearly identical to the Meritek variant. This part is supplied in Cut Tape (CT) and Digi-Reel® packaging formats, suitable for automated assembly environments.

Secondary Alternative: SMCJ40A-TR (STMicroelectronics)

The SMCJ40A-TR from STMicroelectronics meets all core substitution criteria with identical reverse standoff voltage and peak pulse power. This variant exhibits higher clamping voltage (84V) and peak pulse current (119A at 8/20µs), which represents a more aggressive transient suppression characteristic. This part is appropriate for applications requiring enhanced clamping performance within the same power envelope. ROHS3 compliance and active production status are confirmed.

All three substitute parts share MSL 1 (unlimited) moisture sensitivity, eliminating bake-out requirements for storage and handling. Selection among these options should be based on supply chain availability, packaging format requirements, and specific clamping voltage performance needs for the target application.

Frequently Asked Questions (FAQ)

Q: Can the SMCJ40A-TR substitute for the 1SMC40AT3 if the application requires lower clamping voltage?

A: The SMCJ40A-TR exhibits 84V clamping voltage compared to the 64.5V specification of other SMCJ40A variants. If the circuit design depends on clamping voltage below 70V, the SMCJ40A (Meritek) or SMCJ40A-13-F (Diodes Incorporated) are more appropriate selections.

Q: Are all substitute parts compatible with the same PCB footprint?

A: Yes. All substitute parts use DO-214AB (SMC) surface mount packaging, which maintains identical mechanical dimensions and land pattern compatibility with the original 1SMC40AT3.

Q: What is the significance of the different peak pulse current ratings (23.26A vs. 119A)?

A: Peak pulse current is a derived parameter reflecting the diode's internal resistance and thermal characteristics at the specified clamping voltage. All parts maintain the same 1500W peak pulse power rating. The higher current rating in the SMCJ40A-TR indicates lower internal resistance, resulting in more aggressive voltage clamping.

Q: Does the RoHS3 compliance of substitute parts affect circuit performance?

A: RoHS3 compliance indicates the absence of restricted substances (lead, cadmium, mercury, etc.) in the component composition. This is a regulatory and environmental specification that does not alter electrical performance or functional compatibility.

Q: Can the 1SMC40AT3 be used in new designs despite its obsolete status?

A: The 1SMC40AT3 is classified as obsolete, indicating onsemi has discontinued production and support. New designs should specify one of the active substitute parts to ensure long-term supply chain viability and manufacturer support.

Q: What packaging formats are available for the substitute parts?

A: The SMCJ40A (Meritek) is available in standard packaging. The SMCJ40A-13-F (Diodes Incorporated) is supplied in Cut Tape (CT) and Digi-Reel® formats, optimized for high-volume automated assembly. The SMCJ40A-TR (STMicroelectronics) is available in Cut Tape (CT) and Digi-Reel® packaging.