3KASMC28AHM3_A/H Equivalent & Substitute Parts

Part Overview

The 3KASMC28AHM3_A/H 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 is rated for 28V reverse standoff voltage with a 45.4V maximum clamping voltage and 66.1A peak pulse current capability, delivering 3000W peak pulse power dissipation. The part carries automotive-grade qualification (AEC-Q101) and is RoHS3 compliant with MSL 1 rating.

The 3KASMC28AHM3_A/H is currently listed as obsolete. Equivalent and substitute parts are available from multiple manufacturers with identical or comparable electrical specifications and the same surface mount packaging, ensuring direct functional replacement in circuit designs.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	28	V
Voltage - Breakdown (Min)	31.1	V
Voltage - Clamping (Max) @ Ipp	45.4	V
Current - Peak Pulse (10/1000µs)	66.1	A
Power - Peak Pulse	3000	W
Type	Zener	—
Unidirectional Channels	1	—
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
Operating Temperature Range	-65°C ~ 185°C (TJ)	—
RoHS Status	RoHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the 3KASMC28AHM3_A/H are selected based on strict electrical and mechanical compatibility criteria. All substitute candidates must meet the following requirements:

Critical Matching Parameters:

Voltage - Reverse Standoff (Typ): 28V
Voltage - Breakdown (Min): 31.1V
Voltage - Clamping (Max) @ Ipp: 45.4V
Current - Peak Pulse (10/1000µs): 66.1A
Power - Peak Pulse: 3000W
Type: Zener, Unidirectional
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
RoHS Status: RoHS3 Compliant

Substitute parts are grouped into two categories:

Category 1: Direct Electrical & Mechanical Equivalents (Preferred) Parts with identical electrical specifications, same package, and active product status. These include 3KASMC28AHM3_B/H (Vishay), 3.0SMCJ28A-13 (Diodes Incorporated), SM30T33AY (STMicroelectronics), SMDJ28A (Alpha & Omega Semiconductor), SMDJ28A-HR (Littelfuse), SMDJ28A-HRA (Littelfuse), SMDJ28A-HRAT7 (Littelfuse), and TPSMD28A (Littelfuse).

Category 2: Manufacturer-Recommended Alternatives Parts with modified electrical specifications or compliance status but recommended by the original manufacturer. These include 1SMC28A TR13 TIN/LEAD (Central Semiconductor Corp) with reduced peak pulse current (33A) and power (1.5kW), and 3.0SMC28A (Littelfuse) with increased clamping voltage (59V) and peak pulse current (470A at 8/20µs).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Breakdown Min (V)	Voltage - Clamping Max @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temp (°C)	Product Status	RoHS Status
3KASMC28AHM3_A/H	Vishay	28	31.1	45.4	66.1	3000	-65 ~ 185	Obsolete	RoHS3
3KASMC28AHM3_B/H	Vishay	28	31.1	45.4	66.1	3000	-65 ~ 185	Active	RoHS3
3.0SMCJ28A-13	Diodes Incorporated	28	31.1	45.4	66.1	3000	-55 ~ 175	Active	RoHS3
SM30T33AY	STMicroelectronics	28	31.1	45.4	66.1	3000	-55 ~ 175	Active	RoHS3
SMDJ28A	Alpha & Omega Semiconductor	28	31.1	45.4	66.1	3000	-55 ~ 150	Active	RoHS3
SMDJ28A-HR	Littelfuse	28	31.1	45.4	66.1	3000	-65 ~ 150	Active	RoHS3
SMDJ28A-HRA	Littelfuse	28	31.1	45.4	66.1	3000	-65 ~ 150	Active	RoHS3
SMDJ28A-HRAT7	Littelfuse	28	31.1	45.4	66.1	3000	-65 ~ 150	Active	RoHS3
TPSMD28A	Littelfuse	28	31.1	45.4	66.1	3000	-65 ~ 150	Active	RoHS3
1SMC28A TR13 TIN/LEAD	Central Semiconductor Corp	28	31.1	45.4	33	1500	-65 ~ 150	Active	RoHS Non-compliant
3.0SMC28A	Littelfuse	28	31.1	59	470 (8/20µs)	—	-65 ~ 150	Active	RoHS3

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

The 3KASMC28AHM3_B/H from Vishay is the optimal substitute, offering identical electrical specifications and the same operating temperature range (-65°C ~ 185°C) as the obsolete 3KASMC28AHM3_A/H. Both parts carry AEC-Q101 automotive qualification and RoHS3 compliance. The primary difference is packaging format (Tape & Reel vs. bulk), which does not affect electrical performance.

For applications requiring active product status with full electrical equivalence, the following parts are suitable:

3.0SMCJ28A-13 (Diodes Incorporated): Identical electrical specifications, active status, RoHS3 compliant. Operating temperature range is -55°C ~ 175°C, which is acceptable for most applications but does not extend to the full -65°C lower limit.
SM30T33AY (STMicroelectronics): Identical electrical specifications, active status, AEC-Q101 qualified, RoHS3 compliant. Operating temperature range is -55°C ~ 175°C.
SMDJ28A (Alpha & Omega Semiconductor): Identical electrical specifications, active status, RoHS3 compliant. Operating temperature range is -55°C ~ 150°C.
SMDJ28A-HR, SMDJ28A-HRA, SMDJ28A-HRAT7 (Littelfuse): All three variants offer identical electrical specifications, active status, and RoHS3 compliance with operating temperature range -65°C ~ 150°C.
TPSMD28A (Littelfuse): Identical electrical specifications, active status, AEC-Q101 qualified, RoHS3 compliant. Operating temperature range is -65°C ~ 150°C.

Alternative Substitutes (Application-Dependent):

The 1SMC28A TR13 TIN/LEAD (Central Semiconductor Corp) maintains the same voltage ratings but delivers reduced peak pulse current (33A vs. 66.1A) and power dissipation (1.5kW vs. 3kW). This part is RoHS non-compliant and should only be selected for applications where reduced surge current handling is acceptable and RoHS compliance is not required.

The 3.0SMC28A (Littelfuse) maintains the same 28V reverse standoff voltage but increases the clamping voltage to 59V and peak pulse current to 470A (8/20µs pulse). This part is suitable only for applications where higher surge current capacity and increased clamping voltage are beneficial or required.

Frequently Asked Questions (FAQ)

Q: Can I use 3KASMC28AHM3_B/H as a direct replacement for 3KASMC28AHM3_A/H?

A: Yes. Both parts are manufactured by Vishay with identical electrical specifications (28V standoff, 45.4V clamping, 66.1A peak pulse, 3000W power), the same DO-214AB (SMC) package, and equivalent operating temperature ranges. The primary difference is packaging format (Tape & Reel vs. bulk). Both carry AEC-Q101 qualification and RoHS3 compliance.

Q: What is the key difference between the primary substitutes?

A: All primary substitutes (3.0SMCJ28A-13, SM30T33AY, SMDJ28A variants, TPSMD28A) maintain identical electrical specifications and package type. The differences are manufacturer, operating temperature range, and product series designation. Selection depends on availability, supply chain preference, and specific temperature requirements. Parts rated to -65°C (Vishay 3KASMC28AHM3_B/H, Littelfuse SMDJ28A-HR/HRA/HRAT7, TPSMD28A) are preferred for applications requiring extended low-temperature operation.

Q: Why is 1SMC28A TR13 TIN/LEAD listed as a substitute if it has lower current and power ratings?

A: This part is listed as a manufacturer-recommended alternative by the original supplier. It maintains the same voltage ratings (28V standoff, 45.4V clamping) but with reduced surge current handling (33A vs. 66.1A) and power dissipation (1.5kW vs. 3kW). It is suitable only for applications where the lower surge current capacity is acceptable. Additionally, this part is RoHS non-compliant, making it unsuitable for applications requiring RoHS3 compliance.

Q: Can I use 3.0SMC28A as a substitute?

A: The 3.0SMC28A maintains the same 28V reverse standoff voltage but differs significantly in clamping voltage (59V vs. 45.4V) and peak pulse current (470A at 8/20µs vs. 66.1A at 10/1000µs). This part is suitable only for applications where higher surge current capacity and increased clamping voltage are required or beneficial. It is not a direct electrical equivalent and should only be selected when the modified specifications align with circuit requirements.

Q: Are all substitute parts RoHS3 compliant?

A: No. The 1SMC28A TR13 TIN/LEAD is RoHS non-compliant. All other substitutes listed are RoHS3 compliant. For applications requiring RoHS compliance, exclude the 1SMC28A TR13 TIN/LEAD from consideration.

Q: What is the operating temperature difference between substitutes?

A: The original 3KASMC28AHM3_A/H and its direct equivalent 3KASMC28AHM3_B/H operate from -65°C to 185°C. Most active substitutes operate from -55°C to 175°C or -65°C to 150°C. For applications requiring operation below -55°C or above 175°C, verify the specific substitute's temperature range. The Vishay 3KASMC28AHM3_B/H maintains the full -65°C to 185°C range.

Q: Do all substitutes use the same DO-214AB (SMC) package?

A: Yes. All listed substitutes use the DO-214AB (SMC) surface mount package, ensuring mechanical and footprint compatibility with the original 3KASMC28AHM3_A/H design.

Q: Which substitute has the best availability?

A: According to inventory data, SMDJ28A (Alpha & Omega Semiconductor) has the highest stock level at 41,900 pieces. TPSMD28A (Littelfuse) has 4,168 pieces in stock. Availability varies by distributor and should be verified at the time of procurement.

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