3KASMC12AHE3_A/I Equivalent & Substitute Parts

Part Overview

The 3KASMC12AHE3_A/I is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, designed for surface mount applications in the DO-214AB (SMC) package. This component operates with a 12V reverse standoff voltage and provides 19.9V maximum clamping voltage at peak pulse current of 151A, delivering 3000W peak pulse power dissipation. The part is qualified to AEC-Q101 automotive standards and complies with ROHS3 and REACH regulations. As this part carries an obsolete product status, equivalent and substitute parts from active manufacturers are necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	12V
Voltage - Breakdown (Min)	13.3V
Voltage - Clamping (Max) @ Ipp	19.9V
Current - Peak Pulse (10/1000µs)	151A
Power - Peak Pulse	3000W
Operating Temperature Range	-65°C ~ 185°C (TJ)
Package / Case	DO-214AB, SMC
Mounting Type	Surface Mount
Type	Zener
Unidirectional Channels	1
Grade	Automotive
Qualification	AEC-Q101
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 3KASMC12AHE3_A/I is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

Voltage - Reverse Standoff: 12V
Voltage - Breakdown (Min): 13.3V
Voltage - Clamping (Max) @ Ipp: 19.9V
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
Unidirectional Channels: 1
Type: Zener

Allowable Variation Parameters:

Current - Peak Pulse (10/1000µs): 75.4A to 252A (equal to or greater than 151A acceptable for direct substitution; lower values represent reduced capability)
Power - Peak Pulse: 1500W to 5000W (equal to or greater than 3000W acceptable for direct substitution; lower values represent reduced capability)
Operating Temperature Range: Minimum -55°C acceptable (original -65°C); Maximum 150°C to 185°C acceptable
Product Status: Active preferred over obsolete for procurement continuity
Compliance: ROHS3 and REACH status maintained across substitutes

Substitute parts are grouped into two categories: direct equivalents (matching all critical parameters with equal or superior electrical performance) and functional alternatives (meeting voltage and package requirements with reduced current/power ratings suitable for lower-stress applications).

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse	Power - Peak Pulse	Operating Temperature	Package	Product Status	Qualification
3KASMC12AHE3_A/I	Vishay	12V	19.9V	151A	3000W	-65°C ~ 185°C	DO-214AB (SMCJ)	Obsolete	AEC-Q101
3KASMC12AHE3_B/I	Vishay	12V	19.9V	151A	3000W	-65°C ~ 185°C	DO-214AB (SMC)	Active	AEC-Q101
SMC30J12A	STMicroelectronics	12V	19.9V	151A	3000W	-55°C ~ 175°C	DO-214AB (SMC)	Active	Not specified
5.0SMDJ12A	HY Electronic (Cayman) Limited	12V	19.9V	252A	5000W	-65°C ~ 150°C	DO-214AB (SMCJ)	Active	Not specified
SMCJ12A	MDD	12V	19.9V	75.4A	1500W	-50°C ~ 150°C	DO-214AB (SMC)	Active	Not specified
SMCJ12A-HRA	Littelfuse Inc.	12V	19.9V	75.4A	1500W	-65°C ~ 150°C	DO-214AB (SMCJ)	Active	Not specified
SMCJ12A-TP	Micro Commercial Co	12V	19.9V	75.4A	1500W	-55°C ~ 175°C	DO-214AB (SMC)	Active	Not specified
SMDJ12A	Alpha & Omega Semiconductor Inc.	12V	19.9V	150.8A	3000W	-55°C ~ 150°C	DO-214AB	Active	Not specified

Engineering Selection Recommendations

Direct Equivalents (Preferred for 1:1 Replacement):

3KASMC12AHE3_B/I from Vishay is the primary direct equivalent, maintaining identical electrical specifications (151A peak pulse current, 3000W power dissipation, 19.9V clamping voltage) and operating temperature range (-65°C ~ 185°C). This part carries active product status and AEC-Q101 qualification, ensuring design continuity with the obsolete 3KASMC12AHE3_A/I.

SMDJ12A from Alpha & Omega Semiconductor Inc. provides equivalent electrical performance (150.8A peak pulse current, 3000W power dissipation) in the DO-214AB package with active product status. Operating temperature range is -55°C ~ 150°C, which is acceptable for most applications not requiring the full -65°C lower limit.

Enhanced Performance Alternative:

5.0SMDJ12A from HY Electronic (Cayman) Limited offers superior current handling (252A peak pulse) and power dissipation (5000W) while maintaining the same voltage specifications and DO-214AB (SMCJ) package. This part is suitable for applications requiring higher transient stress margins. Operating temperature range is -65°C ~ 150°C.

Reduced Capability Alternatives (Lower Stress Applications):

SMCJ12A from MDD, SMCJ12A-HRA from Littelfuse Inc., and SMCJ12A-TP from Micro Commercial Co all provide the same voltage specifications (12V standoff, 19.9V clamping) in DO-214AB packages with reduced current ratings (75.4A) and power dissipation (1500W). These parts are suitable for applications where transient stress levels are lower than the original design specification. All three maintain ROHS3 compliance and active product status.

Compliance Considerations:

All substitute parts listed maintain ROHS3 compliance. The original 3KASMC12AHE3_A/I carries AEC-Q101 automotive qualification; substitute parts from Vishay (3KASMC12AHE3_B/I) and STMicroelectronics (SMC30J12A) maintain this qualification level. Other manufacturers' parts do not specify AEC-Q101 qualification in the provided data; applications requiring automotive-grade components should prioritize Vishay or STMicroelectronics alternatives.

Frequently Asked Questions (FAQ)

Q: Can SMCJ12A (75.4A) be used as a direct replacement for 3KASMC12AHE3_A/I (151A)?

A: SMCJ12A maintains identical voltage specifications (12V standoff, 19.9V clamping) and package format (DO-214AB, SMC). However, the reduced peak pulse current (75.4A versus 151A) and power dissipation (1500W versus 3000W) represent lower transient stress capability. This part is suitable only for applications where actual transient stress levels are confirmed to be within the 75.4A / 1500W limits. Circuit analysis is required to determine compatibility.

Q: What is the difference between 3KASMC12AHE3_A/I and 3KASMC12AHE3_B/I?

A: Both parts are manufactured by Vishay with identical electrical specifications and operating temperature ranges. The primary difference is product status: 3KASMC12AHE3_A/I is obsolete, while 3KASMC12AHE3_B/I is active. The packaging designation differs slightly (SMCJ versus SMC), but both use the DO-214AB case. 3KASMC12AHE3_B/I is the recommended replacement for procurement continuity.

Q: Does operating temperature range affect substitution eligibility?

A: Operating temperature range is a secondary parameter. The original part operates -65°C ~ 185°C. Substitute parts with reduced lower limits (e.g., -55°C) are acceptable if the application does not require operation below -55°C. Reduced upper limits (e.g., 150°C versus 185°C) may affect high-temperature reliability margins. Applications requiring the full -65°C ~ 185°C range should prioritize 3KASMC12AHE3_B/I or 5.0SMDJ12A.

Q: Is AEC-Q101 qualification required for my application?

A: AEC-Q101 qualification is mandatory for automotive-grade applications. If your design requires automotive qualification, select from Vishay (3KASMC12AHE3_B/I) or verify STMicroelectronics (SMC30J12A) qualification status with the manufacturer. Other substitute parts do not specify AEC-Q101 qualification in available data.

Q: Can 5.0SMDJ12A be used instead of the original part?

A: Yes. 5.0SMDJ12A maintains all critical voltage specifications and uses the same DO-214AB (SMCJ) package. The enhanced current rating (252A) and power dissipation (5000W) provide superior transient stress margin compared to the original 151A / 3000W specification. Operating temperature range is -65°C ~ 150°C, which covers the lower limit but has a reduced upper limit of 150°C versus the original 185°C.

Q: What packaging differences exist between substitute parts?

A: All substitute parts use the DO-214AB case in either SMC or SMCJ variant designations. These are mechanically and electrically equivalent package formats suitable for the same PCB footprint. Tape & Reel (TR) packaging is available for several substitutes (3KASMC12AHE3_B/I, SMC30J12A, SMCJ12A-HRA, SMCJ12A-TP, SMDJ12A), which affects procurement and handling but not electrical performance or board-level compatibility.

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