SMAJ18A-M3/61 Equivalent & Substitute Parts

Part Overview

The SMAJ18A-M3/61 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division. This surface mount component operates in the DO-214AC (SMA) package and is designed for general-purpose transient voltage suppression applications. The part is Active status and RoHS3 compliant. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity when the primary part number becomes unavailable or when alternative packaging formats are required.

Substiute Parts

SMAJ18A-M3/61

Vishay General Semiconductor - Diodes DivisionIn Stock: 936SMAJ18A-M3/61 Datasheet

Current PartRFQ

SMAJ18A-E3/61

Vishay General Semiconductor - Diodes DivisionIn Stock: 23381SMAJ18A-E3/61 Datasheet

DirectRFQ

SMAJ18A

MDDIn Stock: 15558SMAJ18A Datasheet

DirectRFQ

SMAJ18A-13-F

Diodes IncorporatedIn Stock: 25070SMAJ18A-13-F Datasheet

DirectRFQ

SMAJ18A-TP

Micro Commercial CoIn Stock: 4602SMAJ18A-TP Datasheet

DirectRFQ

SM4T21AY

STMicroelectronicsIn Stock: 2947SM4T21AY Datasheet

MFR RecommendedRFQ

SZ1SMA18AT3G

Littelfuse Inc.In Stock: 4173SZ1SMA18AT3G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SMAJ18A-M3/61 are classified based on strict electrical and mechanical parameter matching. The primary substitution criteria are:

Critical Parameters for Substitution:

• Voltage - Reverse Standoff (Typ): 18V
• Voltage - Breakdown (Min): 20V
• Voltage - Clamping (Max) @ Ipp: 29.2V
• Current - Peak Pulse (10/1000µs): 13.7A
• Power - Peak Pulse: 400W
• Package / Case: DO-214AC, SMA
• Mounting Type: Surface Mount
• Unidirectional Channels: 1

Grouping Categories:

Group 1: Direct Electrical & Mechanical Equivalents Parts with identical electrical specifications and DO-214AC (SMA) package configuration. Differences are limited to packaging format (Tape & Reel vs. Cut Tape) and manufacturer variants.

Group 2: Manufacturer Variants with Identical Specifications Parts from different manufacturers (MDD, Diodes Incorporated, Micro Commercial Co) with matching electrical parameters and SMA package format.

Group 3: Manufacturer-Recommended Alternatives Parts designated as manufacturer-recommended substitutes. These may have variations in peak pulse current measurement standards or clamping voltage specifications while maintaining the same reverse standoff voltage and general application suitability.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical Performance):

SMAJ18A-E3/61, SMAJ18A (MDD), SMAJ18A-13-F, SMAJ18A-TP, and SZ1SMA18AT3G are suitable direct substitutes for the SMAJ18A-M3/61. These parts maintain identical reverse standoff voltage (18V), breakdown voltage (20V), clamping voltage (29.2V), and peak pulse current (13.7A) specifications. All are RoHS3 compliant and MSL 1 rated. Selection among these alternatives should be based on packaging format availability (Tape & Reel vs. Cut Tape), operating temperature range requirements, and manufacturer inventory status.

Manufacturer-Recommended Alternative:

SM4T21AY (STMicroelectronics) is designated as a manufacturer-recommended substitute. This part maintains the same reverse standoff voltage (18V) and breakdown voltage (20V) as the primary part. However, it exhibits a higher clamping voltage (39.3V) and significantly higher peak pulse current (59A at 8/20µs measurement standard). This part is AEC-Q101 qualified for automotive applications. Selection of SM4T21AY should be limited to applications where the higher clamping voltage and increased current handling capability are acceptable or beneficial.

Temperature Range Considerations:

SMAJ18A-TP offers an extended upper operating temperature limit (-55°C ~ 175°C TA) compared to the primary part (-55°C ~ 150°C TJ). SZ1SMA18AT3G provides an extended lower temperature limit (-65°C ~ 150°C TJ). These variants are suitable when thermal performance requirements exceed the primary part specification.

Compliance & Certification:

All substitute parts maintain RoHS3 compliance and MSL 1 rating. SZ1SMA18AT3G and SM4T21AY carry AEC-Q101 automotive qualification. Selection should align with application-specific compliance requirements.

Frequently Asked Questions (FAQ)

Q: Can SMAJ18A-E3/61 be used as a direct replacement for SMAJ18A-M3/61?

A: Yes. SMAJ18A-E3/61 is a direct electrical equivalent with identical voltage and current specifications. The primary difference is packaging format: SMAJ18A-E3/61 is supplied in Cut Tape (CT) format while SMAJ18A-M3/61 is Tape & Reel (TR). Both are manufactured by Vishay and are suitable for identical applications.

Q: What is the difference between SMAJ18A-M3/61 and SM4T21AY?

A: Both parts share the same reverse standoff voltage (18V) and breakdown voltage (20V). However, SM4T21AY has a higher clamping voltage (39.3V vs. 29.2V) and higher peak pulse current rating (59A vs. 13.7A). SM4T21AY is AEC-Q101 qualified. Use SM4T21AY only when higher clamping voltage and current handling are required or acceptable for your application.

Q: Are all substitute parts in the same DO-214AC (SMA) package?

A: Yes. All listed substitute parts use the DO-214AC (SMA) surface mount package. This ensures mechanical and electrical compatibility with PCB layouts designed for the SMAJ18A-M3/61.

Q: What is the difference between Tape & Reel and Cut Tape packaging?

A: Tape & Reel (TR) packaging supplies components on continuous tape wound on reels, suitable for automated assembly lines. Cut Tape (CT) packaging supplies components on tape segments cut to specific lengths, suitable for manual assembly or smaller production runs. Electrical performance is identical; selection depends on assembly process requirements.

Q: Can SZ1SMA18AT3G replace SMAJ18A-M3/61 in automotive applications?

A: Yes. SZ1SMA18AT3G maintains identical electrical specifications and is AEC-Q101 qualified for automotive use. It also provides an extended lower operating temperature range (-65°C vs. -55°C). It is suitable for automotive applications requiring this qualification.

Q: What is the operating temperature range difference between SMAJ18A-TP and SMAJ18A-M3/61?

A: SMAJ18A-TP operates from -55°C to 175°C (TA), while SMAJ18A-M3/61 operates from -55°C to 150°C (TJ). SMAJ18A-TP provides 25°C additional upper temperature margin. Selection should be based on thermal environment requirements of the application.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are RoHS3 compliant and MSL 1 rated, meeting environmental and moisture sensitivity requirements equivalent to the primary part.