1SMC43AT3G Transient Voltage Suppressor Equivalent & Substitute Parts

Part Overview

The 1SMC43AT3G 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 43V reverse standoff voltage with a 69.4V maximum clamping voltage and 21.6A peak pulse current capability in a DO-214AB (SMC) package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for new designs or production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	43	V
Voltage - Breakdown (Min)	47.8	V
Voltage - Clamping (Max) @ Ipp	69.4	V
Current - Peak Pulse (10/1000µs)	21.6	A
Power - Peak Pulse	1500	W
Package / Case	DO-214AB, SMC	—
Operating Temperature Range	-65 to 150	°C (TJ)
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the 1SMC43AT3G is determined by strict equivalence in the following electrical parameters: voltage rating (43V reverse standoff, 47.8V minimum breakdown, 69.4V maximum clamping), unidirectional channel configuration (1 channel), and zener diode type. Mechanical compatibility requires surface-mount packaging in DO-214AB (SMC) or compatible form factors. Substitute parts are grouped into three categories based on peak pulse current and power dissipation capacity:

Category 1 (1500W, 21.6–21.7A): Direct electrical and thermal equivalents with identical power ratings. These parts maintain the original thermal design margins and are suitable for direct replacement in existing layouts.

Category 2 (3000W, 43.2–43.3A): Enhanced current handling with doubled power dissipation. These parts provide increased transient protection margin and are suitable for applications requiring higher surge immunity.

Category 3 (5000W, 72.1A): Maximum current handling with significantly increased power dissipation. These parts are suitable for high-energy transient environments and provide the highest protection margin.

All substitute parts maintain compliance with RoHS3 and EAR99 export classification. Product status (active vs. obsolete) and operating temperature range are secondary selection criteria based on application requirements.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Package	Operating Temp (°C)	Product Status
1SMC43AT3G	Littelfuse Inc.	43	69.4	21.6	1500	DO-214AB, SMC	-65 to 150	Obsolete
SMCJ43A	MDD	43	69.4	21.7	1500	DO-214AB, SMC	-50 to 150	Active
SMCJ43A-HR	Littelfuse Inc.	43	69.4	21.7	1500	DO-214AB, SMC	-65 to 150	Active
SMCJ43A-HRA	Littelfuse Inc.	43	69.4	21.7	1500	DO-214AB, SMC	-65 to 150	Active
SMCJ43A-HRAT7	Littelfuse Inc.	43	69.4	21.7	1500	DO-214AB, SMC	-65 to 150	Active
SMCG43AHE3/57T	Vishay General Semiconductor - Diodes Division	43	69.4	21.6	1500	DO-215AB, SMC Gull Wing	-55 to 150	Active
SMDJ43A	Alpha & Omega Semiconductor Inc.	43	69.4	43.3	3000	DO-214AB, SMC	-55 to 150	Active
SMDJ43A-T7	Littelfuse Inc.	43	69.4	43.2	3000	DO-214AB, SMC	-65 to 150	Active
5.0SMDJ43A	Taiwan Semiconductor Corporation	43	69.4	72.1	5000	DO-214AB, SMC	-55 to 175	Active
5.0SMDJ43A-T7	Littelfuse Inc.	43	69.4	72.1	5000	DO-214AB, SMC	-65 to 150	Active

Engineering Selection Recommendations

Direct Replacement (1500W Category): For applications requiring exact electrical and thermal equivalence to the 1SMC43AT3G, select from SMCJ43A-HR, SMCJ43A-HRA, or SMCJ43A-HRAT7 (all Littelfuse Inc., active status). These parts maintain the original -65°C to 150°C operating temperature range and are available in tape and reel packaging. SMCJ43A (MDD) provides equivalent electrical performance with a reduced lower operating temperature limit of -50°C.

Enhanced Protection (3000W Category): SMDJ43A-T7 (Littelfuse Inc.) and SMDJ43A (Alpha & Omega Semiconductor Inc.) provide doubled peak pulse current and power dissipation while maintaining the 43V voltage rating and DO-214AB package. These are suitable for applications with higher transient energy requirements. SMDJ43A-T7 maintains the -65°C lower temperature limit.

Maximum Protection (5000W Category): 5.0SMDJ43A-T7 (Littelfuse Inc.) and 5.0SMDJ43A (Taiwan Semiconductor Corporation) provide the highest current handling and power dissipation. 5.0SMDJ43A-T7 maintains the -65°C lower temperature limit and is recommended for high-energy transient environments.

Package Consideration: SMCG43AHE3/57T (Vishay General Semiconductor) uses DO-215AB (SMC Gull Wing) packaging and includes AEC-Q101 automotive qualification. This part is suitable only if the PCB layout accommodates the gull-wing form factor and automotive-grade reliability is required.

All recommended substitutes are RoHS3 compliant and EAR99 classified. Selection should prioritize active product status and compliance with application temperature requirements.

Frequently Asked Questions (FAQ)

Q: Can SMCJ43A-HR be used as a direct replacement for 1SMC43AT3G?

A: Yes. SMCJ43A-HR maintains identical electrical parameters (43V standoff, 69.4V clamping, 21.7A peak pulse, 1500W power) and the same operating temperature range (-65°C to 150°C). Both use DO-214AB (SMC) packaging. The primary difference is product status: 1SMC43AT3G is obsolete while SMCJ43A-HR is active.

Q: What is the difference between SMCJ43A and SMDJ43A?

A: Both maintain the 43V voltage rating and 69.4V clamping voltage. SMCJ43A delivers 21.7A peak pulse and 1500W power dissipation. SMDJ43A delivers 43.2–43.3A peak pulse and 3000W power dissipation. SMDJ43A is suitable for applications requiring higher transient current handling. Both use DO-214AB (SMC) packaging.

Q: Can I use 5.0SMDJ43A-T7 in place of 1SMC43AT3G?

A: Electrically, yes. 5.0SMDJ43A-T7 maintains the 43V voltage rating and 69.4V clamping voltage. However, it delivers 72.1A peak pulse and 5000W power dissipation compared to the original 21.6A and 1500W. This higher capability may not be necessary for all applications and could affect thermal design. Use only if the application requires enhanced transient protection or if thermal analysis confirms compatibility.

Q: Does SMCG43AHE3/57T require PCB layout changes?

A: Yes. SMCG43AHE3/57T uses DO-215AB (SMC Gull Wing) packaging instead of the standard DO-214AB (SMC) package. The gull-wing form factor requires different PCB footprint and soldering approach. This part is suitable only if the PCB layout is redesigned to accommodate the gull-wing package.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts are RoHS3 compliant and EAR99 classified, matching the compliance profile of the original 1SMC43AT3G.

Q: What is the operating temperature difference between SMCJ43A and SMCJ43A-HR?

A: SMCJ43A (MDD) operates from -50°C to 150°C. SMCJ43A-HR (Littelfuse Inc.) operates from -65°C to 150°C. If the application requires operation below -50°C, SMCJ43A-HR is required.

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