SMBJ28 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMBJ28 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 47.67V clamping at peak pulse current. The SMBJ28 is classified as obsolete, necessitating identification of active equivalent and substitute 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)	13.3	A
Power - Peak Pulse	600	W
Operating Temperature Range	-65 to 150	°C (TJ)
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the SMBJ28 is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

Voltage - Reverse Standoff: 28V (exact match required)
Voltage - Breakdown (Min): 29.48V to 31.1V (acceptable range)
Voltage - Clamping (Max) @ Ipp: 45.4V to 47.67V (acceptable range)
Current - Peak Pulse (10/1000µs): 13.2A to 22A (acceptable range for general-purpose applications)
Power - Peak Pulse: 600W to 1000W (acceptable range)
Package / Case: DO-214AA, SMB (exact match required)
Mounting Type: Surface Mount (exact match required)
RoHS Status: ROHS3 Compliant (required for regulatory compliance)

Substitute parts are grouped into two categories based on peak pulse current capability:

Category A - Standard Current Rating (13.2A to 13.8A): Direct electrical equivalents with identical peak pulse current specifications. These parts are suitable for direct replacement in applications where the original 13.3A rating is specified.

Category B - Enhanced Current Rating (22A): Higher peak pulse current capability with increased power dissipation (1000W vs. 600W). These parts provide additional margin for transient protection but maintain the same voltage parameters and package form factor.

Parameter Comparison

Part Number	Manufacturer	Product Status	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temp Range (°C)	Package
SMBJ28	Littelfuse Inc.	Obsolete	28	47.67	13.3	600	-65 to 150	DO-214AA, SMB
SMBJ28A	MDD	Active	28	45.4	13.3	600	-50 to 150	DO-214AA, SMB
SZ1SMB28AT3G	Littelfuse Inc.	Active	28	45.4	13.2	600	-65 to 150	DO-214AA, SMB
SMB10J28A-E3/52	Vishay General Semiconductor - Diodes Division	Active	28	45.4	22	1000	-55 to 150	DO-214AA, SMB
SMB10J28A-E3/5B	Vishay General Semiconductor - Diodes Division	Active	28	45.4	22	1000	-55 to 150	DO-214AA, SMB
SMBJ28A-13-F	Diodes Incorporated	Active	28	45.4	13.2	600	-55 to 150	DO-214AA, SMB
SMBJ28A-E3/5B	Vishay General Semiconductor - Diodes Division	Active	28	45.5	13.2	600	-55 to 150	DO-214AA, SMB
SMBJ28A-TP	Micro Commercial Co	Active	28	45.4	13.2	600	-55 to 175	DO-214AA, SMB
SMBJ28A-TR	STMicroelectronics	Active	28	45.4	13.8	600	-55 to 150	DO-214AA, SMB

Engineering Selection Recommendations

Primary Substitutes (Category A - Standard Current Rating):

SMBJ28A-E3/5B (Vishay General Semiconductor - Diodes Division) and SMBJ28A-TP (Micro Commercial Co) are the preferred direct replacements. Both maintain the 28V reverse standoff voltage, 45.4V to 45.5V clamping voltage, and 13.2A peak pulse current. SMBJ28A-E3/5B is manufactured by Littelfuse's subsidiary and carries the TransZorb® series designation. SMBJ28A-TP extends the upper operating temperature to 175°C, providing additional thermal margin for high-temperature environments.

SZ1SMB28AT3G (Littelfuse Inc.) is an active Littelfuse product with AEC-Q101 automotive qualification. This part maintains the original -65°C lower temperature limit and is suitable for automotive and industrial applications requiring enhanced reliability standards.

SMBJ28A-13-F (Diodes Incorporated) and SMBJ28A-TR (STMicroelectronics) are functionally equivalent alternatives with 13.2A and 13.8A peak pulse current respectively, both within acceptable substitution parameters.

Secondary Substitute (Category B - Enhanced Current Rating):

SMB10J28A-E3/52 and SMB10J28A-E3/5B (Vishay General Semiconductor - Diodes Division) provide 22A peak pulse current and 1000W power dissipation. These parts are suitable for applications requiring higher transient protection margin or where circuit design permits the use of enhanced current ratings. Both are active products with full RoHS3 compliance.

Temperature Consideration:

The original SMBJ28 operates from -65°C to 150°C. Most active substitutes operate from -55°C to 150°C, representing a 10°C reduction in the lower temperature limit. SMBJ28A-TP extends to 175°C at the upper limit. Applications requiring the full -65°C lower limit should specify SZ1SMB28AT3G.

Compliance and Availability:

All substitute parts are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating. All listed parts are currently in active production status with substantial inventory availability.

Frequently Asked Questions (FAQ)

Q: Can SMBJ28A directly replace SMBJ28 in existing designs?

A: Yes. SMBJ28A maintains the critical electrical parameters: 28V reverse standoff voltage, 45.4V clamping voltage, 13.3A peak pulse current, and 600W power dissipation. The DO-214AA SMB package is identical. The primary difference is product status (active vs. obsolete) and a 10°C reduction in the lower operating temperature limit (-50°C vs. -65°C for MDD variant).

Q: What is the difference between Category A and Category B substitutes?

A: Category A substitutes (SMBJ28A-E3/5B, SMBJ28A-TP, SMBJ28A-13-F, SMBJ28A-TR) maintain the original 13.2A to 13.8A peak pulse current and 600W power dissipation. Category B substitutes (SMB10J28A-E3/52, SMB10J28A-E3/5B) provide 22A peak pulse current and 1000W power dissipation, offering higher transient protection capability. Both categories maintain the 28V reverse standoff voltage and DO-214AA SMB package.

Q: Are there temperature range differences between substitutes?

A: Yes. The original SMBJ28 operates from -65°C to 150°C. Most active substitutes operate from -55°C to 150°C. SMBJ28A-TP extends to 175°C at the upper limit. SZ1SMB28AT3G maintains the -65°C lower limit. Applications requiring full -65°C to 150°C operation should specify SZ1SMB28AT3G or SMBJ28A-TP depending on upper temperature requirements.

Q: Is the DO-214AA SMB package identical across all substitutes?

A: Yes. All listed substitute parts use the DO-214AA SMB surface-mount package. Mechanical compatibility and PCB footprint are identical. No layout modifications are required for substitution.

Q: What certifications apply to these substitute parts?

A: All substitute parts are ROHS3 compliant. SZ1SMB28AT3G carries AEC-Q101 automotive qualification. All parts have MSL 1 (Unlimited) moisture sensitivity rating, indicating no special storage or handling requirements.

Q: Which substitute offers the best compatibility with the original SMBJ28?

A: SZ1SMB28AT3G (Littelfuse Inc.) offers the highest compatibility, as it is manufactured by the original equipment supplier, maintains the -65°C lower temperature limit, and carries automotive-grade qualification. SMBJ28A-E3/5B (Vishay General Semiconductor - Diodes Division) is also a strong choice, being part of the TransZorb® series with established market presence.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message