Request Quote
(Ships tomorrow)
3KASMC18AHM3_A/I Equivalent & Substitute Parts
Part Overview
The 3KASMC18AHM3_A/I is an 18V 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 Zener diode provides transient overvoltage protection with a peak pulse power rating of 3000W and peak pulse current of 93.2A at 32.2V clamping voltage. The part is qualified to AEC-Q101 automotive standards and operates across -65°C to 185°C junction temperature range. As this part carries an obsolete product status, equivalent and substitute parts with active availability are necessary for ongoing design support and procurement continuity.
Substiute Parts
Key Parameters
| Parameter | Value |
|---|---|
| Voltage - Reverse Standoff (Typ) | 18V |
| Voltage - Breakdown (Min) | 20V |
| Voltage - Clamping (Max) @ Ipp | 32.2V |
| Current - Peak Pulse (10/1000µs) | 93.2A |
| Power - Peak Pulse | 3000W |
| Operating Temperature Range | -65°C ~ 185°C (TJ) |
| Package / Case | DO-214AB, SMC |
| Grade | Automotive |
| Qualification | AEC-Q101 |
| RoHS Status | ROHS3 Compliant |
Substitute Part Grouping Explanation
Substitution eligibility for the 3KASMC18AHM3_A/I is determined by the following critical parameters:
- Voltage - Reverse Standoff: 18V (primary voltage rating)
- Voltage - Breakdown (Min): 20V (minimum trigger threshold)
- Package / Case: DO-214AB, SMC (mechanical and electrical compatibility)
- Unidirectional Channels: 1 (circuit topology requirement)
- Type: Zener (functional classification)
Substitute parts must maintain the 18V standoff voltage and 20V minimum breakdown voltage to ensure proper circuit protection function. The DO-214AB SMC package is mandatory for PCB footprint compatibility. Peak pulse current and clamping voltage may vary within acceptable ranges for the application, provided the part remains rated for transient overvoltage suppression in the specified voltage class.
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 | Package | Product Status |
|---|---|---|---|---|---|---|---|---|---|
| 3KASMC18AHM3_A/I | Vishay | 18V | 20V | 32.2V | 93.2A | 3000W | -65°C ~ 185°C | DO-214AB (SMC) | Obsolete |
| 3KASMC18AHM3_B/I | Vishay | 18V | 20V | 29.2V | 103A | 3000W | -65°C ~ 185°C | DO-214AB (SMC) | Active |
| SMLJ18E3/TR13 | Microchip Technology | 18V | 20V | 32.2V | 93.2A | 300W | -55°C ~ 150°C | DO-214AB (SMC) | Active |
| 5.0SMDJ18A | Taiwan Semiconductor Corporation | 18V | 20V | 29.2V | 172A | 5000W | -55°C ~ 175°C | DO-214AB (SMC) | Active |
| SMCJ18A | MDD | 18V | 20V | 29.2V | 51.4A | 1500W | -50°C ~ 150°C | DO-214AB (SMC) | Active |
| SMCJ18A-HR | Littelfuse Inc. | 18V | 20V | 29.2V | 51.4A | 1500W | -65°C ~ 150°C | DO-214AB (SMC) | Active |
| SMCJ18A-HRA | Littelfuse Inc. | 18V | 20V | 29.2V | 51.4A | 1500W | -65°C ~ 150°C | DO-214AB (SMC) | Active |
Engineering Selection Recommendations
Direct Replacement (Highest Compatibility): The 3KASMC18AHM3_B/I from Vishay is the primary direct replacement. It maintains identical voltage ratings (18V standoff, 20V breakdown), package format (DO-214AB SMC), and automotive qualification (AEC-Q101). Operating temperature range matches the original (-65°C ~ 185°C). This part is currently in active production status with 1044 units in stock.
Automotive-Grade Alternatives: The SMCJ18A-HR and SMCJ18A-HRA from Littelfuse Inc. are qualified alternatives for automotive applications. Both maintain the 18V/20V voltage specification and DO-214AB SMC package. Operating temperature range extends to -65°C minimum, matching the original specification. These parts are active and available (932 and 811 units respectively).
General-Purpose Alternatives: The 5.0SMDJ18A from Taiwan Semiconductor Corporation offers higher peak pulse power (5000W) and current (172A) while maintaining voltage compatibility. Operating temperature range is -55°C ~ 175°C, which is narrower than the original but suitable for many applications. This part has the highest inventory availability (18400 units).
The SMLJ18E3/TR13 from Microchip Technology provides identical clamping voltage (32.2V) and peak pulse current (93.2A) to the original part. However, peak pulse power is reduced to 300W, and operating temperature range is -55°C ~ 150°C. This part is suitable only for applications where the reduced power rating is acceptable.
The SMCJ18A from MDD provides the lowest peak pulse specifications (51.4A, 1500W) and narrowest operating temperature range (-50°C ~ 150°C). Selection of this part requires confirmation that application requirements do not exceed these ratings.
Voltage Deviation: The SMCJ16A from EVVO Semi operates at 16V standoff with 17.8V minimum breakdown. This part does not meet the 18V standoff requirement and is not suitable as a direct substitute.
Frequently Asked Questions (FAQ)
Q: Can I use a substitute part with different peak pulse power rating? A: Yes, provided the substitute part's power rating meets or exceeds your circuit's transient energy requirements. The 3KASMC18AHM3_A/I is rated for 3000W peak pulse. Parts rated at 5000W (5.0SMDJ18A) provide additional margin. Parts rated below 3000W (SMCJ18A at 1500W, SMLJ18E3 at 300W) require application analysis to confirm adequacy.
Q: Does operating temperature range affect substitution? A: Yes. The original part operates -65°C ~ 185°C. Substitutes with narrower ranges may not be suitable for all applications. The 3KASMC18AHM3_B/I and Littelfuse SMCJ18A-HR/-HRA maintain the -65°C minimum. Parts with -55°C minimum or -50°C minimum have reduced low-temperature capability.
Q: Are all substitute parts automotive-qualified? A: No. Only the 3KASMC18AHM3_B/I (Vishay), SMCJ18A-HR, and SMCJ18A-HRA (Littelfuse) carry AEC-Q101 automotive qualification. General-purpose alternatives (MDD SMCJ18A, Microchip SMLJ18E3, Taiwan Semiconductor 5.0SMDJ18A) are not automotive-qualified and are suitable only for non-automotive applications.
Q: What is the difference between SMCJ18A-HR and SMCJ18A-HRA? A: Both parts from Littelfuse maintain identical electrical specifications (18V standoff, 20V breakdown, 29.2V clamping, 51.4A peak pulse, 1500W power, -65°C ~ 150°C operating range) and DO-214AB SMC package. The suffix designations indicate different product variants within the Littelfuse SMCJ-HR series. Electrical compatibility is equivalent.
Q: Can I substitute a part with higher peak pulse current? A: Yes. Higher peak pulse current (172A in 5.0SMDJ18A versus 93.2A in the original) provides additional transient suppression capability without compromising circuit function. The voltage ratings remain the same, ensuring proper protection threshold.
Q: Is the DO-214AB SMC package mandatory? A: Yes. The original part uses DO-214AB (SMC) surface mount package. All listed substitutes use the same package for PCB footprint compatibility. Parts in different packages (such as DO-214AC SMA) are not mechanically compatible.
Alternative Parts
SJ6012L2TP
Littelfuse Inc.
6 Alternative Parts
JMK107BBJ476MA-RE
Taiyo Yuden
10 Alternative Parts
GMK107BBJ475MA-T
Taiyo Yuden
5 Alternative Parts
SJ6020N2ARP
Littelfuse Inc.
3 Alternative Parts
SJ6025R2ATP
Littelfuse Inc.
4 Alternative Parts
2474-05L
API Delevan Inc.
1 Alternative Parts
4590R-684K
API Delevan Inc.
1 Alternative Parts
CM6560R-334
API Delevan Inc.
1 Alternative Parts
CM6460-104
API Delevan Inc.
1 Alternative Parts
5526-12
API Delevan Inc.
1 Alternative Parts