3KASMC40HE3_A/H Equivalent & Substitute Parts

Part Overview

The 3KASMC40HE3_A/H is a unidirectional transient voltage suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, rated for 40V reverse standoff voltage with a 71.4V maximum clamping voltage. This component is designed for surface mount applications in the DO-214AB (SMC) package and operates across the automotive temperature range of -65°C to 185°C. The part is currently listed as obsolete, making equivalent substitutes necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	3KASMC40HE3_A/H
Manufacturer	Vishay General Semiconductor - Diodes Division
Category	Transient Voltage Suppressors (TVS)
Type	Zener, Unidirectional
Voltage - Reverse Standoff (Typ)	40V
Voltage - Breakdown (Min)	44.4V
Voltage - Clamping (Max) @ Ipp	71.4V
Current - Peak Pulse (10/1000µs)	42A
Power - Peak Pulse	3000W (3kW)
Package / Case	DO-214AB, SMC
Operating Temperature	-65°C ~ 185°C (TJ)
Grade	Automotive
Qualification	AEC-Q101
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the 3KASMC40HE3_A/H is determined by the following critical parameters:

Voltage - Reverse Standoff (Typ): Must be 40V
Voltage - Breakdown (Min): Must be 44.4V
Package / Case: Must be DO-214AB or SMC
Type: Must be Zener, Unidirectional
Mounting Type: Must be Surface Mount
Unidirectional Channels: Must be 1

Substitute parts are grouped into two categories based on electrical performance alignment:

Category A - Direct Electrical Match (71.4V Clamping): Parts with identical clamping voltage (71.4V) and peak pulse current (42A), maintaining the same power dissipation profile (3000W).

Category B - Functional Equivalents (64.5V Clamping): Parts with lower clamping voltage (64.5V) but higher peak pulse current ratings (46.5A or greater), providing equivalent or superior transient suppression capability within the same power class or higher.

Category C - Enhanced Performance (5000W Rating): Parts with significantly higher power dissipation capability (5000W) and peak pulse current (77.6A), suitable for applications requiring additional margin.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Package	Product Status
3KASMC40HE3_A/H	Vishay	40V	44.4V	71.4V	42A	3000W	-65°C ~ 185°C	DO-214AB (SMCJ)	Obsolete
3KASMC40AHE3_B/H	Vishay	40V	44.4V	64.5V	46.5A	3000W	-65°C ~ 185°C	DO-214AB (SMC)	Active
SMLJ40E3/TR13	Microchip Technology	40V	44.4V	71.4V	42A	300W	-55°C ~ 150°C	DO-214AB (SMC)	Active
5.0SMDJ40A	Taiwan Semiconductor Corporation	40V	44.4V	64.5V	77.6A	5000W	-55°C ~ 175°C	DO-214AB (SMC)	Active
SMCJ40A	Meritek	40V	44.4V	64.5V	23.26A	1500W	-55°C ~ 150°C	DO-214AB (SMC)	Active
SMCJ40A-13-F	Diodes Incorporated	40V	44.4V	64.5V	23.2A	1500W	-55°C ~ 150°C	DO-214AB (SMC)	Active
SMCJ40A-TR	STMicroelectronics	40V	44.4V	84V	119A (8/20µs)	1500W	-55°C ~ 150°C	DO-214AB (SMC)	Active
SMDJ40A	Alpha & Omega Semiconductor Inc.	40V	44.4V	64.5V	46.6A	3000W	-55°C ~ 150°C	DO-214AB (SMC)	Active
SMDJ40A-T7	Littelfuse Inc.	40V	44.4V	64.5V	46.5A	3000W	-65°C ~ 150°C	DO-214AB (SMCJ)	Active

Engineering Selection Recommendations

For Automotive Applications with AEC-Q101 Requirement:

The 3KASMC40AHE3_B/H (Vishay) is the primary substitute. It maintains the same manufacturer lineage, automotive grade designation, AEC-Q101 qualification, and extended operating temperature range (-65°C to 185°C). The lower clamping voltage (64.5V vs. 71.4V) is offset by higher peak pulse current (46.5A vs. 42A), providing equivalent transient suppression performance. This part is active and available in volume.

For General Purpose Applications with Extended Temperature Range:

The SMDJ40A-T7 (Littelfuse Inc.) provides a functional equivalent with active product status and maintains the lower temperature limit of -65°C. It delivers 46.5A peak pulse current at 3000W power dissipation, matching the original part's energy handling capability.

For Applications Requiring Enhanced Transient Protection:

The 5.0SMDJ40A (Taiwan Semiconductor Corporation) offers superior performance with 5000W peak pulse power and 77.6A peak pulse current. This part is suitable for applications where additional margin against transient events is required, though it operates within a narrower temperature range (-55°C to 175°C).

For Cost-Optimized Designs:

The SMCJ40A (Meritek) and SMCJ40A-13-F (Diodes Incorporated) are available at lower power ratings (1500W) and reduced peak pulse current (23.2A to 23.26A). These parts are suitable only for applications where the original 3kW specification exceeds actual transient energy requirements.

Temperature Consideration:

Applications requiring the full -65°C to 185°C operating range are limited to the 3KASMC40AHE3_B/H and SMDJ40A-T7. All other substitutes operate within -55°C to 175°C or -55°C to 150°C ranges.

Frequently Asked Questions (FAQ)

Q: Can the 3KASMC40AHE3_B/H directly replace the 3KASMC40HE3_A/H?

A: Yes. Both parts share the same 40V reverse standoff voltage, 44.4V breakdown voltage, and DO-214AB package. The 3KASMC40AHE3_B/H has a lower clamping voltage (64.5V vs. 71.4V) but higher peak pulse current (46.5A vs. 42A), maintaining equivalent 3000W power dissipation. Both are automotive-grade with AEC-Q101 qualification.

Q: What is the difference between clamping voltage and reverse standoff voltage?

A: Reverse standoff voltage (40V) is the maximum voltage the diode can withstand without conducting. Clamping voltage (71.4V or 64.5V) is the voltage at which the diode clamps during a transient event at specified peak pulse current. Lower clamping voltage provides tighter voltage regulation during transients.

Q: Why do some substitutes have lower power ratings?

A: The SMCJ40A and SMCJ40A-13-F are rated at 1500W versus the original 3000W. These parts are suitable only if your application's actual transient energy is below 1500W. Using a lower-rated part in a 3000W application risks component failure.

Q: Is the SMLJ40E3/TR13 a suitable substitute despite its 300W rating?

A: No. Although it matches the 71.4V clamping voltage and 42A peak pulse current, the 300W power rating is significantly below the original 3000W specification. This part is unsuitable for the same application.

Q: Can I use the 5.0SMDJ40A in place of the original part?

A: Yes, with temperature range consideration. The 5.0SMDJ40A provides superior performance (5000W, 77.6A) but operates only to 175°C versus the original 185°C maximum. It is suitable for applications not requiring the full upper temperature limit.

Q: What does "DO-214AB (SMC)" packaging mean?

A: DO-214AB is the industry standard package designation for surface mount diodes. SMC (Surface Mount Case) is the physical form factor. All listed substitutes use this same package, ensuring mechanical and electrical compatibility on PCBs designed for the original part.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitutes carry ROHS3 Compliant status, matching the original part's environmental compliance requirement.

Q: Which substitute offers the best balance of availability and performance?

A: The 3KASMC40AHE3_B/H (Vishay) and SMDJ40A-T7 (Littelfuse Inc.) both provide active product status, equivalent 3000W power handling, and automotive-grade specifications. The 3KASMC40AHE3_B/H maintains the full -65°C to 185°C temperature range, while SMDJ40A-T7 extends to -65°C minimum but limits to 150°C maximum.

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