3KASMC12HE3_A/H Equivalent & Substitute Parts

Part Overview

The 3KASMC12HE3_A/H is a unidirectional transient voltage suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division. This surface mount component operates at 12V reverse standoff voltage with a 22V maximum clamping voltage and 136A peak pulse current rating. The device is designed for transient overvoltage protection in automotive-grade applications and carries AEC-Q101 qualification.

The 3KASMC12HE3_A/H is classified as obsolete. Substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Manufacturer Part Number	3KASMC12HE3_A/H
Manufacturer	Vishay General Semiconductor - Diodes Division
Category	Transient Voltage Suppressors (TVS)
Type	Zener, Unidirectional
Package / Case	DO-214AB, SMC
Voltage - Reverse Standoff (Typ)	12V
Voltage - Breakdown (Min)	13.3V
Voltage - Clamping (Max) @ Ipp	22V
Current - Peak Pulse (10/1000µs)	136A
Power - Peak Pulse	3000W (3kW)
Operating Temperature	-65°C ~ 185°C (TJ)
Mounting Type	Surface Mount
Grade	Automotive
Qualification	AEC-Q101
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the 3KASMC12HE3_A/H is determined by the following critical parameters:

Voltage - Reverse Standoff: 12V (required match)
Voltage - Breakdown (Min): 13.3V (required match)
Package / Case: DO-214AB, SMC (required match for PCB compatibility)
Mounting Type: Surface Mount (required match)
Unidirectional Channels: 1 (required match)

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

Category A: Direct Electrical Equivalents — Parts with 19.9V maximum clamping voltage (lower than original 22V) and peak pulse currents ranging from 75.4A to 252A. These parts maintain the same reverse standoff and breakdown voltages while offering different power dissipation and current handling capabilities.

Category B: Enhanced Performance Alternatives — Parts with higher peak pulse current ratings (150.8A to 252A) and 3000W to 5000W power ratings, suitable for applications requiring greater transient energy absorption.

All substitute parts maintain DO-214AB (SMC) surface mount packaging and unidirectional topology, ensuring mechanical and electrical compatibility with the original design footprint.

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	Product Status
3KASMC12HE3_A/H	Vishay General Semiconductor - Diodes Division	12V	13.3V	22V	136A	3000W	-65°C ~ 185°C	Obsolete
3KASMC12AHE3_B/H	Vishay General Semiconductor - Diodes Division	12V	13.3V	19.9V	151A	3000W	-65°C ~ 185°C	Active
5.0SMDJ12A	HY Electronic (Cayman) Limited	12V	13.3V	19.9V	252A	5000W	-65°C ~ 150°C	Active
SMCJ12A	MDD	12V	13.3V	19.9V	75.4A	1500W	-50°C ~ 150°C	Active
SMCJ12A-HRA	Littelfuse Inc.	12V	13.3V	19.9V	75.4A	1500W	-65°C ~ 150°C	Active
SMCJ12A-TP	Micro Commercial Co	12V	13.3V	19.9V	75.4A	1500W	-55°C ~ 175°C	Active
SMDJ12A	Alpha & Omega Semiconductor Inc.	12V	13.3V	19.9V	150.8A	3000W	-55°C ~ 150°C	Active
SMDJ12A-HR	Littelfuse Inc.	12V	13.3V	19.9V	150.8A	3000W	-65°C ~ 150°C	Active

Engineering Selection Recommendations

Primary Recommendation: 3KASMC12AHE3_B/H

The 3KASMC12AHE3_B/H from Vishay General Semiconductor - Diodes Division is the direct successor to the obsolete 3KASMC12HE3_A/H. This part maintains identical reverse standoff voltage (12V), breakdown voltage (13.3V), and power rating (3000W). The clamping voltage is reduced to 19.9V, and peak pulse current is increased to 151A. The part carries active product status, ROHS3 compliance, and AEC-Q101 automotive qualification. Operating temperature range matches the original (-65°C ~ 185°C), ensuring compatibility with automotive-grade applications.

Secondary Recommendation: SMDJ12A or SMDJ12A-HR

For applications where 3000W power dissipation is required and the original 136A peak pulse current is adequate, SMDJ12A (Alpha & Omega Semiconductor Inc.) or SMDJ12A-HR (Littelfuse Inc.) provide equivalent electrical performance. Both parts deliver 150.8A peak pulse current and 3000W power rating. SMDJ12A-HR extends the lower operating temperature to -65°C, matching the original specification. Both parts are active and ROHS3 compliant.

Alternative for Lower Current Applications: SMCJ12A-HRA or SMCJ12A-TP

If the application requires only 75.4A peak pulse current and 1500W power dissipation, SMCJ12A-HRA (Littelfuse Inc.) or SMCJ12A-TP (Micro Commercial Co) are suitable alternatives. SMCJ12A-HRA maintains the -65°C lower temperature limit. SMCJ12A-TP extends the upper operating temperature to 175°C. Both are active, ROHS3 compliant, and available in high inventory quantities.

Enhanced Performance Option: 5.0SMDJ12A

For applications requiring maximum transient energy absorption, 5.0SMDJ12A (HY Electronic) provides 252A peak pulse current and 5000W power rating. This part is suitable for high-energy transient environments. Operating temperature range is -65°C ~ 150°C. ROHS3 compliance is confirmed; REACH status is affected.

All substitute parts maintain DO-214AB (SMC) surface mount packaging and unidirectional topology, ensuring direct PCB footprint compatibility.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with a lower clamping voltage (19.9V vs. 22V)?

A: Yes. The 19.9V clamping voltage of substitute parts is within acceptable tolerance for 12V standoff voltage applications. Lower clamping voltage provides tighter voltage regulation during transient events. Verify that your circuit design accommodates the reduced clamping voltage threshold.

Q: What is the difference between SMCJ12A and SMDJ12A?

A: Both parts share identical voltage specifications (12V standoff, 13.3V breakdown, 19.9V clamping). The primary difference is peak pulse current: SMCJ12A delivers 75.4A with 1500W power rating, while SMDJ12A delivers 150.8A with 3000W power rating. Select SMDJ12A for higher transient energy applications.

Q: Are all substitute parts automotive-grade?

A: The 3KASMC12AHE3_B/H, SMDJ12A-HR, and SMCJ12A-HRA carry AEC-Q101 automotive qualification. SMCJ12A-TP, SMDJ12A, SMCJ12A-HRA, and 5.0SMDJ12A are not explicitly listed with automotive qualification. Verify AEC-Q101 compliance with your supplier if automotive-grade certification is required for your application.

Q: Is the DO-214AB (SMC) package identical across all substitute parts?

A: Yes. All substitute parts use DO-214AB (SMC) surface mount packaging. PCB footprint compatibility is maintained across all listed alternatives. No layout modifications are required.

Q: What is the impact of operating temperature range differences?

A: The original part operates from -65°C to 185°C. Most substitute parts operate to -65°C or -55°C at the lower limit and 150°C at the upper limit. If your application requires operation above 150°C, verify that the selected substitute part meets your thermal requirements. SMCJ12A-TP extends to 175°C upper temperature.

Q: Can I use 5.0SMDJ12A as a direct replacement?

A: 5.0SMDJ12A is electrically compatible but offers enhanced performance (252A peak pulse, 5000W power). It is suitable for applications requiring greater transient energy absorption. Operating temperature range is -65°C ~ 150°C. REACH status is affected; verify compliance requirements for your application.

Q: Why do some parts have different peak pulse current ratings?

A: Peak pulse current rating reflects the maximum transient current the device can safely absorb during a 10/1000µs pulse. Higher current ratings indicate greater transient energy handling capability. Select a part with peak pulse current equal to or greater than your circuit's maximum transient current requirement.

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