3KASMC18AHE3_A/H Transient Voltage Suppressor Diode - Equivalent & Substitute Parts

Part Overview

The 3KASMC18AHE3_A/H is an 18V Zener transient voltage suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, designed for surface mount applications in the DO-214AB (SMC) package. This unidirectional TVS diode provides 29.2V clamping voltage at 103A peak pulse current with 3000W peak pulse power dissipation. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	18	V
Voltage - Breakdown (Min)	20	V
Voltage - Clamping (Max) @ Ipp	29.2	V
Current - Peak Pulse (10/1000µs)	103	A
Power - Peak Pulse	3000	W
Operating Temperature Range	-65 to 185	°C (TJ)
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution eligibility for the 3KASMC18AHE3_A/H is determined by the following critical parameters:

Mandatory Matching Parameters:

Voltage - Reverse Standoff (Typ): 18V
Voltage - Breakdown (Min): 20V
Voltage - Clamping (Max) @ Ipp: 29.2V
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
Type: Zener
Unidirectional Channels: 1

Allowable Variation Parameters:

Current - Peak Pulse (10/1000µs): Equal to or greater than 103A
Power - Peak Pulse: Equal to or greater than 3000W
Operating Temperature Range: Equal to or exceeding -65°C to 185°C
RoHS Status: ROHS3 Compliant or equivalent
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts must maintain identical voltage specifications and package form factor while supporting equal or superior current handling and power dissipation capabilities. Operating temperature range may be narrower if the application does not require the full -65°C to 185°C span.

Parameter Comparison

Part Number	Manufacturer	Vwm (V)	Vbr (V)	Vc @ Ipp (V)	Ipp (A)	Ppk (W)	Temp Range (°C)	Package	Status
3KASMC18AHE3_A/H	Vishay	18	20	29.2	103	3000	-65 to 185	DO-214AB (SMC)	Obsolete
3KASMC18AHE3_B/H	Vishay	18	20	29.2	103	3000	-65 to 185	DO-214AB (SMC)	Active
SMC30J18A	STMicroelectronics	18	20	29.2	103	3000	-55 to 175	DO-214AB (SMC)	Active
5.0SMDJ18A	Taiwan Semiconductor Corporation	18	20	29.2	172	5000	-55 to 175	DO-214AB (SMC)	Active
SMCJ18A	MDD	18	20	29.2	51.4	1500	-50 to 150	DO-214AB (SMC)	Active
SMCJ18A-HR	Littelfuse Inc.	18	20	29.2	51.4	1500	-65 to 150	DO-214AB (SMC)	Active
SMCJ18A-HRA	Littelfuse Inc.	18	20	29.2	51.4	1500	-65 to 150	DO-214AB (SMC)	Active
SMCJ16A	EVVO Semi	16	17.8	26	57.7	600	-65 to 150	DO-214AC (SMA)	Active

Engineering Selection Recommendations

Direct Equivalents (Recommended for Replacement):

3KASMC18AHE3_B/H is the primary direct equivalent. This part maintains identical electrical specifications (18V standoff, 20V breakdown, 29.2V clamping, 103A peak pulse, 3000W peak power) and package form factor while offering active product status. The only difference is packaging format (Tape & Reel versus bulk), which does not affect electrical performance.

Compatible Alternatives (Voltage and Package Match):

SMC30J18A (STMicroelectronics) and 5.0SMDJ18A (Taiwan Semiconductor Corporation) maintain the required 18V/20V/29.2V voltage specifications and DO-214AB (SMC) package compatibility. SMC30J18A provides equivalent current and power ratings (103A, 3000W) with a narrower operating temperature range (-55°C to 175°C). The 5.0SMDJ18A offers enhanced performance with 172A peak pulse current and 5000W peak power dissipation, suitable for applications requiring higher transient energy absorption.

Partial Compatibility (Voltage Match, Reduced Performance):

SMCJ18A (MDD), SMCJ18A-HR, and SMCJ18A-HRA maintain the 18V/20V/29.2V voltage specifications and DO-214AB (SMC) package but provide reduced peak pulse current (51.4A) and power dissipation (1500W). These parts are suitable only for applications with lower transient energy requirements than the original specification.

Not Recommended:

SMCJ16A (EVVO Semi) does not meet substitution criteria. The 16V standoff voltage, 17.8V breakdown voltage, and 26V clamping voltage differ from the required 18V/20V/29.2V specifications. Additionally, the package is DO-214AC (SMA) rather than DO-214AB (SMC), requiring PCB layout modification.

Frequently Asked Questions (FAQ)

Q: Can I use 3KASMC18AHE3_B/H as a direct replacement for 3KASMC18AHE3_A/H?

A: Yes. Both parts are identical in electrical specifications and package form factor. The difference is packaging format (Tape & Reel versus bulk). Electrical performance and PCB compatibility are unchanged.

Q: What is the difference between SMC30J18A and 5.0SMDJ18A?

A: Both maintain the required 18V standoff and 29.2V clamping voltages. SMC30J18A provides 103A peak pulse current and 3000W power dissipation, matching the original part. The 5.0SMDJ18A provides enhanced performance with 172A peak pulse current and 5000W power dissipation, allowing it to handle larger transient events. The 5.0SMDJ18A has a narrower operating temperature range (-55°C to 175°C versus -65°C to 185°C).

Q: Why is SMCJ18A listed as a substitute if it has lower current and power ratings?

A: SMCJ18A maintains the critical voltage specifications (18V standoff, 20V breakdown, 29.2V clamping) and package form factor. However, its 51.4A peak pulse current and 1500W power dissipation are insufficient for applications requiring the full 103A/3000W capability of the original part. Use SMCJ18A only if your circuit design requires less than 51.4A peak pulse current.

Q: Can I use SMCJ16A as a substitute?

A: No. SMCJ16A has a 16V standoff voltage and 26V clamping voltage, which do not match the required 18V/29.2V specifications. Additionally, it uses a different package (DO-214AC SMA instead of DO-214AB SMC), requiring PCB redesign. This part is not electrically or mechanically compatible.

Q: What does "Tape & Reel (TR)" packaging mean?

A: Tape & Reel is an automated packaging format where components are mounted on a continuous carrier tape wound on a reel, suitable for high-volume automated assembly. Bulk packaging contains loose components. Both formats contain identical components; the difference is handling and assembly method.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 Compliant status, meeting the same environmental and hazardous substance restrictions as the original 3KASMC18AHE3_A/H.

Q: What is the significance of the operating temperature range difference?

A: The original part operates from -65°C to 185°C (TJ). Some substitutes have narrower ranges (e.g., -55°C to 175°C). If your application requires operation at temperatures below -55°C or above 175°C, select a substitute with a matching or wider temperature range. For most commercial and industrial applications operating within -40°C to 85°C, the narrower range is acceptable.

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