Equivalent & Substitute Parts for 3KASMC33AHM3_A/I TVS Diode

Part Overview

The 3KASMC33AHM3_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 33V reverse standoff voltage and provides 3000W peak pulse power dissipation. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain identical electrical and mechanical specifications for continued circuit protection functionality.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	33	V
Voltage - Breakdown (Min)	36.7	V
Voltage - Clamping (Max) @ Ipp	53.3	V
Current - Peak Pulse (10/1000µs)	56.3	A
Power - Peak Pulse	3000	W
Operating Temperature Range	-65°C ~ 185°C	TJ
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
AEC-Q101 Qualification	Yes	—

Substitute Part Grouping Explanation

Substitution of the 3KASMC33AHM3_A/I is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff: 33V (±tolerance)
Voltage - Breakdown (Min): 36.7V
Voltage - Clamping (Max) @ Ipp: 53.3V
Current - Peak Pulse (10/1000µs): 56.3A
Power - Peak Pulse: 3000W
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
RoHS Compliance: ROHS3 Compliant

Substitute parts are grouped into two categories:

Category 1: Direct Electrical & Mechanical Equivalents (3000W, 56.3A) Parts maintaining identical clamping voltage (53.3V), peak pulse current (56.3A), and power dissipation (3000W). These parts are fully interchangeable at the circuit level.

Category 2: Higher Power Alternatives (5000W, 93.9A) Parts with identical voltage specifications but increased power handling (5000W) and peak pulse current (93.9A). These provide enhanced transient protection margin and are suitable for applications requiring higher energy absorption.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temp (°C)	Product Status	AEC-Q101
3KASMC33AHM3_A/I	Vishay	33	53.3	56.3	3000	-65 ~ 185	Obsolete	Yes
3KASMC33AHM3_B/I	Vishay	33	53.3	56.3	3000	-65 ~ 185	Active	Yes
SM30T39AY	STMicroelectronics	33	53.3	56.3	3000	-55 ~ 175	Active	Yes
SMDJ33A	Alpha & Omega Semiconductor	33	53.3	56.3	3000	-55 ~ 150	Active	No
SMDJ33A-HR	Littelfuse	33	53.3	56.3	3000	-65 ~ 150	Active	No
SMDJ33A-HRA	Littelfuse	33	53.3	56.3	3000	-65 ~ 150	Active	No
SMDJ33A-HRAT7	Littelfuse	33	53.3	56.3	3000	-65 ~ 150	Active	No
TPSMD33A	Littelfuse	33	53.3	56.3	3000	-65 ~ 150	Active	Yes
3.0SMC33A	Littelfuse	33	70	365 (8/20µs)	—	-65 ~ 150	Active	No
5.0SMDJ33A	Taiwan Semiconductor	33	53.3	93.9	5000	-55 ~ 175	Active	No
5.0SMDJ33A-T7	Littelfuse	33	53.3	93.9	5000	-65 ~ 150	Active	No

Engineering Selection Recommendations

Primary Recommendation: 3KASMC33AHM3_B/I This Vishay part is the direct active equivalent of the obsolete 3KASMC33AHM3_A/I. It maintains identical electrical specifications, operating temperature range (-65°C ~ 185°C), and AEC-Q101 automotive qualification. Selection of this part eliminates any performance variance and preserves design intent.

Secondary Recommendation: TPSMD33A Littelfuse TPSMD33A provides full electrical equivalence with AEC-Q101 qualification. Operating temperature range is -65°C ~ 150°C, which is acceptable for most applications except those requiring the full -65°C ~ 185°C range. This part offers high inventory availability (26,400 units).

Alternative for Automotive Applications: SM30T39AY STMicroelectronics SM30T39AY (TRANSIL™ series) maintains identical electrical specifications with AEC-Q101 qualification. Operating temperature range is -55°C ~ 175°C. This part is suitable for automotive applications with standard temperature requirements.

Higher Power Option: 5.0SMDJ33A-T7 For applications requiring enhanced transient protection margin, Littelfuse 5.0SMDJ33A-T7 provides 5000W peak pulse power and 93.9A peak pulse current while maintaining 53.3V clamping voltage. Operating temperature range is -65°C ~ 150°C. This part is recommended only when circuit analysis confirms the need for increased energy absorption capacity.

Not Recommended: 3.0SMC33A Littelfuse 3.0SMC33A exhibits different clamping voltage (70V) and peak pulse current (365A at 8/20µs waveform), making it electrically incompatible with the original design specification.

Frequently Asked Questions (FAQ)

Q: Can I use SMDJ33A as a direct replacement for 3KASMC33AHM3_A/I? A: SMDJ33A maintains identical electrical parameters (33V standoff, 53.3V clamping, 56.3A peak pulse, 3000W power). However, it lacks AEC-Q101 qualification and has a reduced operating temperature range (-55°C ~ 150°C versus -65°C ~ 185°C). Use only if your application does not require automotive qualification or the extended temperature range.

Q: What is the difference between SMDJ33A-HR, SMDJ33A-HRA, and SMDJ33A-HRAT7? A: All three Littelfuse variants maintain identical electrical specifications. The suffix designations indicate different packaging or tape configurations. Electrically, they are equivalent. Verify packaging requirements with your procurement specification before selection.

Q: Why does 3.0SMC33A appear in the substitute list if it has different electrical parameters? A: The 3.0SMC33A was listed in the original part's substitute field but exhibits different clamping voltage (70V) and peak pulse current (365A). It is not a true electrical equivalent and should not be used as a replacement without circuit re-analysis.

Q: Can I use the 5.0SMDJ33A series for higher reliability? A: The 5.0SMDJ33A series provides higher power dissipation (5000W) and peak pulse current (93.9A) while maintaining identical clamping voltage (53.3V). Use this part only if circuit analysis confirms the application benefits from increased transient energy absorption. Standard 3000W designs do not require this upgrade.

Q: Are all substitute parts in the same DO-214AB (SMC) package? A: Yes. All listed substitute parts use the DO-214AB (SMC) surface mount package, ensuring mechanical and footprint compatibility with the original design.

Q: Which substitute part has the best inventory availability? A: TPSMD33A offers the highest inventory (26,400 units), followed by SMDJ33A (230,383 units). However, SMDJ33A lacks AEC-Q101 qualification. For qualified parts, TPSMD33A is the best-stocked option.

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