SMCJ28 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMCJ28 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 28V reverse standoff voltage with a 47.67V maximum clamping voltage at peak pulse current of 33.1A, housed in a DO-214AB (SMC) package. The SMCJ28 is classified as obsolete; equivalent and substitute parts from active manufacturers are available to maintain design continuity and ensure supply chain reliability.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	28	V
Voltage - Breakdown (Min)	29.48	V
Voltage - Clamping (Max) @ Ipp	47.67	V
Current - Peak Pulse (10/1000µs)	33.1	A
Power - Peak Pulse	1500	W
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	DO-214AB, SMC	—
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the SMCJ28 is determined by the following critical parameters:

Voltage - Reverse Standoff: 28V (fixed requirement)
Voltage - Clamping (Max) @ Ipp: 45.4V to 50V (acceptable range for general-purpose protection)
Current - Peak Pulse: 30A to 66.1A (higher values provide enhanced transient suppression capability)
Power - Peak Pulse: 1500W to 3000W (higher power ratings offer improved thermal performance)
Package / Case: DO-214AB, SMC (mechanical and thermal compatibility)
Mounting Type: Surface Mount (assembly process compatibility)
Operating Temperature: -55°C minimum to 150°C or higher (thermal operating envelope)
RoHS Status: ROHS3 Compliant (regulatory requirement)
Moisture Sensitivity Level: 1 (Unlimited) (handling and storage compatibility)

Substitute parts maintain the 28V reverse standoff voltage and DO-214AB package while allowing variation in clamping voltage, peak pulse current, and power dissipation within the specified ranges. All substitutes are from active manufacturers with current production status and full regulatory compliance.

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)	Product Status	RoHS Status
SMCJ28	Littelfuse Inc.	28	47.67	33.1	1500	-55 to 150	Obsolete	ROHS3 Compliant
SMCJ28A	Meritek	28	45.4	33.04	1500	-55 to 150	Active	ROHS3 Compliant
3.0SMCJ28A-13	Diodes Incorporated	28	45.4	66.1	3000	-55 to 175	Active	ROHS3 Compliant
SMCJ28A-13-F	Diodes Incorporated	28	45.4	33	1500	-55 to 150	Active	ROHS3 Compliant
SMCJ28A-TP	Micro Commercial Co	28	45.4	33.1	1500	-55 to 175	Active	ROHS3 Compliant
SMCJ28AE3/TR13	Microchip Technology	28	45.4	33	1500	-65 to 150	Active	ROHS3 Compliant
SMCJ28E3/TR13	Microchip Technology	28	50	30	1500	-65 to 150	Active	ROHS3 Compliant
SMLJ28A	Bourns Inc.	28	45.4	66	3000	-55 to 150	Active	ROHS3 Compliant
SMLJ28A-TP	Micro Commercial Co	28	45.4	66	3000	-55 to 175	Active	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts maintain the 28V reverse standoff voltage and DO-214AB package form factor required for direct replacement. Selection among substitutes depends on application-specific requirements:

Direct Electrical Equivalents (1500W Power Rating, ~33A Peak Pulse Current): SMCJ28A (Meritek), SMCJ28A-13-F (Diodes Incorporated), SMCJ28A-TP (Micro Commercial Co), SMCJ28AE3/TR13 (Microchip Technology), and SMCJ28E3/TR13 (Microchip Technology) provide electrical performance aligned with the original SMCJ28 specification. These parts are suitable for applications where the original 1500W power dissipation and 30–33A peak pulse current are sufficient.

Enhanced Performance Alternatives (3000W Power Rating, 66A Peak Pulse Current): 3.0SMCJ28A-13 (Diodes Incorporated), SMLJ28A (Bourns Inc.), and SMLJ28A-TP (Micro Commercial Co) offer doubled power dissipation and doubled peak pulse current capability. These parts are appropriate for applications requiring enhanced transient suppression margin or higher energy absorption.

Temperature Range Considerations: SMCJ28AE3/TR13 and SMCJ28E3/TR13 (Microchip Technology) extend the lower operating temperature to -65°C. SMCJ28A-TP (Micro Commercial Co) and SMLJ28A-TP (Micro Commercial Co) extend the upper operating temperature to 175°C. Select based on system thermal requirements.

Regulatory and Supply Status: All substitute parts are ROHS3 compliant and carry active product status from established manufacturers, ensuring long-term availability and regulatory alignment.

Frequently Asked Questions (FAQ)

Q: Can SMCJ28A directly replace SMCJ28? A: Yes. SMCJ28A from Meritek maintains the 28V reverse standoff voltage, 45.4V clamping voltage, 33.04A peak pulse current, 1500W power rating, and DO-214AB package. Electrical performance is equivalent for general-purpose transient suppression applications.

Q: What is the difference between SMCJ28A and 3.0SMCJ28A-13? A: Both maintain 28V reverse standoff and 45.4V clamping voltage. The 3.0SMCJ28A-13 provides 66.1A peak pulse current and 3000W power dissipation compared to 33A and 1500W for SMCJ28A. The higher ratings provide enhanced transient energy absorption and thermal performance.

Q: Are SMLJ28A and SMCJ28A interchangeable? A: Both are housed in DO-214AB packages with 28V reverse standoff and 45.4V clamping voltage. SMLJ28A provides 66A peak pulse current and 3000W power rating versus 33A and 1500W for SMCJ28A. Mechanical compatibility is confirmed; electrical performance differs in transient suppression capability.

Q: Does clamping voltage variation affect substitution? A: The SMCJ28 specifies 47.67V maximum clamping voltage. Substitute parts range from 45.4V to 50V. Lower clamping voltages (45.4V) provide tighter voltage regulation; higher clamping voltages (50V) allow slightly more voltage transient before suppression. Selection depends on circuit protection requirements.

Q: Which substitute offers the widest operating temperature range? A: SMCJ28A-TP and SMLJ28A-TP (Micro Commercial Co) extend the upper temperature limit to 175°C. SMCJ28AE3/TR13 and SMCJ28E3/TR13 (Microchip Technology) extend the lower temperature limit to -65°C. Choose based on system thermal environment.

Q: Are all substitutes available in tape and reel packaging? A: Most substitutes are supplied in tape and reel format for automated assembly. Verify packaging specification with the supplier for specific procurement requirements.

Q: What is the significance of the ROHS3 compliance marking? A: ROHS3 compliance confirms the part meets Restriction of Hazardous Substances Directive requirements, ensuring regulatory alignment for applications subject to environmental and safety standards.

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