SMDJ28 Transient Voltage Suppressor (TVS) Diode – Equivalent & Substitute Parts

Part Overview

The SMDJ28 is a unidirectional transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component operates with a 28V reverse standoff voltage and provides peak pulse power dissipation of 3000W in a DO-214AB (SMC) package. The SMDJ28 is classified as obsolete, necessitating identification of active equivalent parts that maintain electrical and mechanical compatibility for new designs and production continuity.

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)	66.1	A
Power – Peak Pulse	3000	W
Package / Case	DO-214AB, SMC	–
Mounting Type	Surface Mount	–
Operating Temperature Range	-65 to 150	°C (TJ)
RoHS Status	ROHS3 Compliant	–
Type	Zener	–
Unidirectional Channels	1	–

Substitute Part Grouping Explanation

Substitution of the SMDJ28 is determined by the following critical parameters:

Voltage Rating: Reverse standoff voltage of 28V and breakdown voltage minimum of 29.48V establish the primary voltage class
Peak Pulse Current: 66.1A at 10/1000µs pulse defines the current handling capability
Peak Pulse Power: 3000W (3kW) establishes the power dissipation class
Package: DO-214AB (SMC) surface-mount package ensures mechanical and thermal compatibility
Mounting Type: Surface mount configuration for automated assembly
Temperature Range: Operating range of -65°C to 150°C (TJ) defines thermal operating limits
Compliance: ROHS3 compliance required for regulatory alignment

Substitute parts are grouped into two categories based on peak pulse power rating:

Category A – Full Power Rating (3000W): Parts with 66A peak pulse current and 3000W power dissipation maintain identical electrical performance to the SMDJ28.

Category B – Reduced Power Rating (1500W): Parts with 33A peak pulse current and 1500W power dissipation provide lower power handling but maintain voltage regulation characteristics within the 28V class.

Parameter Comparison

Part Number	Manufacturer	Voltage – Reverse Standoff (V)	Voltage – Breakdown Min (V)	Voltage – Clamping Max @ Ipp (V)	Current – Peak Pulse (A)	Power – Peak Pulse (W)	Package	Operating Temp (°C)	Product Status
SMDJ28	Littelfuse Inc.	28	29.48	47.67	66.1	3000	DO-214AB, SMC	-65 to 150	Obsolete
SMDJ28A	Alpha & Omega Semiconductor Inc.	28	31.1	45.4	66.1	3000	DO-214AB, SMC	-55 to 150	Active
3.0SMCJ28A-13	Diodes Incorporated	28	31.1	45.4	66.1	3000	DO-214AB, SMC	-55 to 175	Active
SMCJ28A	Meritek	28	31.1	45.4	33.04	1500	DO-214AB, SMC	-55 to 150	Active
SMCJ28A-TP	Micro Commercial Co	28	31.1	45.4	33.1	1500	DO-214AB, SMC	-55 to 175	Active
SMCJ28AE3/TR13	Microchip Technology	28	31.1	45.4	33	1500	DO-214AB, SMC	-65 to 150	Active
SMLJ28A	Bourns Inc.	28	31.1	45.4	66	3000	DO-214AB, SMC	-55 to 150	Active
SMLJ28A-TP	Micro Commercial Co	28	31.1	45.4	66	3000	DO-214AB, SMC	-55 to 175	Active
SMLJ28AE3/TR13	Microchip Technology	28	31.1	45.4	66	300	DO-214AB, SMC	-55 to 150	Active
TV15C280J-G	Comchip Technology	28	31.1	45.4	33.04	1500	DO-214AB, SMC	-55 to 150	Active

Engineering Selection Recommendations

Primary Substitutes (Full Electrical Equivalence – 3000W Class)

SMDJ28A (Alpha & Omega Semiconductor Inc.) and SMLJ28A (Bourns Inc.) provide direct electrical equivalence with 66A peak pulse current and 3000W power dissipation. Both are active products with ROHS3 compliance. SMDJ28A operates within -55°C to 150°C, matching the original temperature range lower bound. SMLJ28A extends to -55°C to 150°C with identical power handling. For applications requiring the full -65°C lower temperature limit of the SMDJ28, neither option extends to -65°C; however, SMCJ28AE3/TR13 (Microchip Technology) maintains -65°C operation but at reduced 1500W power rating.

3.0SMCJ28A-13 (Diodes Incorporated) and SMLJ28A-TP (Micro Commercial Co) both deliver 3000W power dissipation with extended upper temperature ratings to 175°C, providing thermal margin for high-ambient applications. Both maintain ROHS3 compliance and active product status.

Secondary Substitutes (Reduced Power Rating – 1500W Class)

SMCJ28A (Meritek), SMCJ28A-TP (Micro Commercial Co), TV15C280J-G (Comchip Technology), and SMCJ28AE3/TR13 (Microchip Technology) operate at 33A peak pulse current with 1500W power dissipation. These are suitable for applications where peak pulse power requirements do not exceed 1500W. SMCJ28AE3/TR13 uniquely maintains the -65°C lower temperature limit while providing 1500W power handling.

Compliance and Availability

All substitute parts maintain ROHS3 compliance and unidirectional single-channel configuration. Inventory availability ranges from 756 to 23,100 pieces across manufacturers, supporting production requirements. Selection should prioritize active product status and compliance certifications for long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can SMCJ28A (1500W) replace SMDJ28 (3000W) in my application?

A: Substitution depends on actual peak pulse power requirements. If your circuit generates transient pulses below 1500W, SMCJ28A is electrically compatible. If transient energy exceeds 1500W, the reduced power rating may cause thermal stress or component failure. Verify your application's peak pulse power specification before selection.

Q: What is the difference between SMDJ28A and SMLJ28A?

A: Both deliver identical electrical performance: 28V standoff voltage, 66A peak pulse current, and 3000W power dissipation in DO-214AB packages. The primary difference is manufacturer (Alpha & Omega Semiconductor vs. Bourns Inc.). SMDJ28A operates -55°C to 150°C; SMLJ28A operates -55°C to 150°C. Selection can be based on supplier availability and procurement preference.

Q: Why does SMLJ28AE3/TR13 show 300W instead of 3000W power rating?

A: This appears to be a data entry anomaly in the provided specification. SMLJ28AE3/TR13 maintains 66A peak pulse current identical to other 3000W-class parts. Verify the actual power rating with Microchip Technology documentation before design implementation.

Q: Does the clamping voltage difference (47.67V vs. 45.4V) affect circuit performance?

A: The SMDJ28 clamps at 47.67V maximum, while substitute parts clamp at 45.4V maximum. The lower clamping voltage in substitutes provides tighter overvoltage protection. If your circuit requires the higher 47.67V clamping threshold, verify that substitute parts' 45.4V clamping is acceptable for downstream component voltage ratings.

Q: Are all substitute parts available in tape-and-reel packaging?

A: Most substitute parts are available in tape-and-reel (TR) packaging for automated assembly. SMCJ28A (Meritek) and SMCJ28A (Meritek duplicate entry) do not specify packaging format. Confirm packaging availability with your supplier before finalizing procurement specifications.

Q: Which substitute offers the widest operating temperature range?

A: 3.0SMCJ28A-13 (Diodes Incorporated) and SMLJ28A-TP (Micro Commercial Co) both extend to 175°C upper operating temperature, compared to 150°C for most alternatives. For high-temperature applications, these options provide thermal margin. SMCJ28AE3/TR13 (Microchip Technology) uniquely maintains -65°C lower limit while operating to 150°C.

Q: Is the DO-214AB package identical across all substitute parts?

A: Yes. All substitute parts use DO-214AB (SMC) surface-mount package, ensuring mechanical compatibility with existing PCB layouts and automated assembly equipment. No package redesign is required for substitution.

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