SMCJ30 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMCJ30 is a unidirectional Zener-type transient voltage suppressor manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. The device features a 30V reverse standoff voltage with a 50.82V maximum clamping voltage at peak pulse current of 31A, packaged in the DO-214AB (SMC) form factor.

The SMCJ30 is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements. Active alternatives with compatible electrical and mechanical specifications are available from multiple manufacturers.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	30	V
Voltage - Breakdown (Min)	31.55	V
Voltage - Clamping (Max) @ Ipp	50.82	V
Current - Peak Pulse (10/1000µs)	31	A
Power - Peak Pulse	1500	W
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the SMCJ30 is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 30V (exact match required)
Voltage - Clamping (Max) @ Ipp: 48.4V to 50.82V (acceptable range for circuit protection equivalence)
Current - Peak Pulse (10/1000µs): 31A minimum (equal or greater capacity acceptable)
Package / Case: DO-214AB, SMC (identical form factor and pinout)
Mounting Type: Surface Mount (identical assembly compatibility)
RoHS Status: ROHS3 Compliant (regulatory equivalence)

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (31A Peak Pulse Current): Parts with 48.4V clamping voltage and 31A peak pulse current provide direct functional replacement with minimal circuit redesign consideration.

Category B - Enhanced Performance Alternatives (Higher Peak Pulse Current): Parts with 62A or higher peak pulse current and equivalent clamping voltage provide superior transient suppression capability while maintaining circuit compatibility.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temperature (°C)	Package / Case	Product Status
SMCJ30	Littelfuse Inc.	30	50.82	31	1500	-55 to 150	DO-214AB, SMC	Obsolete
SMCJ30A	MDD	30	48.4	31	1500	-50 to 150	DO-214AB, SMC	Active
SZ1SMC30AT3G	Littelfuse Inc.	30	48.4	31	1500	-65 to 150	DO-214AB, SMC	Active
3.0SMCJ30A-13	Diodes Incorporated	30	48.4	62	3000	-55 to 175	DO-214AB, SMC	Active
SMCJ30A-13-F	Diodes Incorporated	30	48.4	31	1500	-55 to 150	DO-214AB, SMC	Active
SMCJ30A-TP	Micro Commercial Co	30	48.4	31	1500	-55 to 175	DO-214AB, SMC	Active
SMCJ30A-TR	STMicroelectronics	30	64.3	156	1500	-55 to 150	DO-214AB, SMC	Active
SMCJ30AE3/TR13	Microchip Technology	30	48.4	31	1500	-65 to 150	DO-214AB, SMC	Active
SMCJ30E3/TR13	Microchip Technology	30	54.6	28	1500	-65 to 150	DO-214AB, SMC	Active

Engineering Selection Recommendations

Primary Recommendation - Direct Replacement: SMCJ30A (MDD), SMCJ30A-13-F (Diodes Incorporated), SMCJ30AE3/TR13 (Microchip Technology), and SMCJ30A-TP (Micro Commercial Co) are direct functional equivalents with 30V reverse standoff, 48.4V clamping voltage, and 31A peak pulse current. All are active products with ROHS3 compliance and MSL 1 rating. These parts are suitable for direct substitution in existing SMCJ30 designs without circuit modification.

Alternative - Littelfuse Active Product: SZ1SMC30AT3G (Littelfuse Inc.) maintains manufacturer continuity with the original SMCJ30 design. This part offers extended operating temperature range (-65°C to 150°C) and AEC-Q101 automotive qualification, providing enhanced reliability for demanding applications.

Enhanced Performance Option: 3.0SMCJ30A-13 (Diodes Incorporated) provides superior transient suppression with 62A peak pulse current and 3000W peak pulse power, while maintaining 30V reverse standoff and 48.4V clamping voltage. This part is suitable for applications requiring higher transient energy absorption capacity.

Consideration - STMicroelectronics Alternative: SMCJ30A-TR (STMicroelectronics) maintains 30V reverse standoff but exhibits higher clamping voltage (64.3V) and significantly higher peak pulse current (156A at 8/20µs). This part is suitable only when circuit design permits higher clamping voltage operation.

Not Recommended: SMCJ30E3/TR13 (Microchip Technology) exhibits 28A peak pulse current, below the 31A specification of the original SMCJ30. This part does not meet minimum performance requirements for direct substitution.

Frequently Asked Questions (FAQ)

Q: Can SMCJ30A (MDD) be used as a direct replacement for SMCJ30 (Littelfuse)? A: Yes. Both parts share identical 30V reverse standoff voltage, 31A peak pulse current, 1500W peak pulse power, and DO-214AB SMC packaging. The SMCJ30A exhibits slightly lower clamping voltage (48.4V vs. 50.82V), which is within acceptable tolerance for general-purpose transient suppression circuits.

Q: What is the difference between SMCJ30A-13-F and SMCJ30A-TP? A: Both parts are functionally equivalent with 30V reverse standoff, 48.4V clamping voltage, and 31A peak pulse current. SMCJ30A-13-F is supplied by Diodes Incorporated in Tape & Reel packaging. SMCJ30A-TP is supplied by Micro Commercial Co in Tape & Reel packaging with extended operating temperature range (-55°C to 175°C vs. -55°C to 150°C).

Q: Is 3.0SMCJ30A-13 suitable for SMCJ30 replacement? A: Yes, with design consideration. The 3.0SMCJ30A-13 maintains 30V reverse standoff and 48.4V clamping voltage but provides doubled peak pulse current (62A vs. 31A) and doubled peak pulse power (3000W vs. 1500W). This part is suitable for applications requiring enhanced transient suppression capability and is backward compatible with SMCJ30 circuit designs.

Q: Why does SMCJ30A-TR show different electrical characteristics? A: SMCJ30A-TR (STMicroelectronics) is a different device variant within the SMCJ30 series. While it maintains 30V reverse standoff voltage, it exhibits higher clamping voltage (64.3V) and significantly higher peak pulse current (156A at 8/20µs). This part is suitable only for applications where circuit design permits higher clamping voltage operation.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All substitute parts listed are ROHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity rating, matching the regulatory and environmental specifications of the original SMCJ30.

Q: What is the temperature range consideration for substitute selection? A: The original SMCJ30 operates from -55°C to 150°C. Substitute parts offer equivalent or extended ranges: SZ1SMC30AT3G and SMCJ30AE3/TR13 extend to -65°C; 3.0SMCJ30A-13 and SMCJ30A-TP extend to 175°C. Select based on application thermal requirements.

Q: Can SMCJ30E3/TR13 replace SMCJ30? A: No. SMCJ30E3/TR13 exhibits 28A peak pulse current, which is below the 31A minimum specification of the original SMCJ30. This part does not meet performance requirements for direct substitution.

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