SMAJ180 Transient Voltage Suppressor Equivalent & Substitute Parts

Part Overview

The SMAJ180 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 180V reverse standoff voltage rating with a 306.6V maximum clamping voltage and 1.4A peak pulse current capability in a DO-214AC (SMA) package. The SMAJ180 is currently listed as obsolete, making equivalent substitute parts necessary for ongoing design support and procurement.

Substiute Parts

SMAJ180

Littelfuse Inc.In Stock: 1127SMAJ180 Datasheet

Current PartRFQ

SMAJ180A

Good-Ark SemiconductorIn Stock: 30402SMAJ180A Datasheet

DirectRFQ

SMAJ180A-TP

Micro Commercial CoIn Stock: 5404SMAJ180A-TP Datasheet

MFR RecommendedRFQ

SMAJ188A-TR

STMicroelectronicsIn Stock: 15414SMAJ188A-TR Datasheet

MFR RecommendedRFQ

TV04A181J-G

Comchip TechnologyIn Stock: 859TV04A181J-G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMAJ180 is determined by the following critical parameters:

• Reverse Standoff Voltage (Typ): 180V — substitute parts must maintain this voltage rating
• Package / Case: DO-214AC (SMA) — mechanical and electrical compatibility requires identical package
• Peak Pulse Power: 400W — substitute parts must support this power dissipation level
• Unidirectional Configuration: Single-channel zener diode topology
• RoHS3 Compliance: Environmental and regulatory requirement
• Moisture Sensitivity Level: MSL 1 (Unlimited) — no moisture sensitivity constraints

Substitute parts are grouped into two categories: direct electrical equivalents with identical clamping voltage characteristics, and functional alternatives with slightly different clamping voltages that remain within acceptable operating parameters for general-purpose protection applications.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Closest Electrical Match):

SMAJ180A (Good-Ark Semiconductor) and SMAJ180A-TP (Micro Commercial Co) are the preferred direct substitutes. Both maintain the 180V reverse standoff voltage, 1.4A peak pulse current, and 400W power rating. The clamping voltage differential (292V vs. 306.6V) represents a 4.8% reduction, which remains within acceptable tolerance for general-purpose transient suppression. Both parts are active products with ROHS3 compliance and MSL 1 rating. SMAJ180A-TP offers extended operating temperature range to 175°C (TA), providing additional thermal margin in high-temperature environments.

Secondary Substitute (Voltage-Variant):

TV04A181J-G (Comchip Technology) maintains the 180V reverse standoff voltage with a clamping voltage of 291.6V and peak pulse current of 1.37A. This part is functionally equivalent for general-purpose protection applications with minimal performance deviation.

Alternative Substitute (Higher Voltage Rating):

SMAJ188A-TR (STMicroelectronics) features an 188V reverse standoff voltage with significantly higher clamping voltage (388V) and peak pulse current (6A at 8/20µs). This part is suitable only for applications where higher transient energy absorption is required and the elevated clamping voltage is acceptable.

All substitute parts maintain DO-214AC (SMA) package compatibility, ROHS3 compliance, and MSL 1 moisture sensitivity rating, ensuring direct mechanical and regulatory compatibility with the original SMAJ180 design.

Frequently Asked Questions (FAQ)

Q: Can SMAJ180A directly replace SMAJ180 in existing designs?

A: Yes. SMAJ180A maintains identical reverse standoff voltage (180V), peak pulse current (1.4A), and power rating (400W) in the same DO-214AC (SMA) package. The 4.8% reduction in clamping voltage (292V vs. 306.6V) is within acceptable tolerance for general-purpose transient suppression circuits.

Q: What is the difference between SMAJ180A and SMAJ180A-TP?

A: Both parts are electrically identical with 180V standoff voltage and 292V clamping voltage. The primary difference is operating temperature range: SMAJ180A-TP supports -55 to 175°C (TA), compared to SMAJ180A at -55 to 150°C (TJ). SMAJ180A-TP is preferred for high-temperature applications.

Q: Why does SMAJ188A-TR have different electrical specifications?

A: SMAJ188A-TR is a higher-voltage variant with 188V reverse standoff voltage, 388V clamping voltage, and 6A peak pulse current. This part is suitable only for applications requiring higher transient energy absorption. The elevated clamping voltage may not be appropriate for circuits designed for the original 180V/306.6V characteristics.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (SMAJ180A, SMAJ180A-TP, TV04A181J-G, and SMAJ188A-TR) are ROHS3 compliant with MSL 1 moisture sensitivity rating, ensuring regulatory and environmental compatibility with the original SMAJ180.

Q: What packaging options are available for substitute parts?

A: All substitute parts are supplied in DO-214AC (SMA) surface-mount package, identical to the original SMAJ180. Packaging formats include Cut Tape (CT), Digi-Reel, and Tape & Reel (TR) options depending on manufacturer and distributor availability.

Q: Can TV04A181J-G be used as a direct replacement?

A: TV04A181J-G is functionally compatible with 180V reverse standoff voltage and 291.6V clamping voltage, representing a 4.8% reduction from the original 306.6V specification. Peak pulse current is 1.37A, slightly below the original 1.4A. This part is suitable for general-purpose protection applications with minimal performance deviation.