SMBJ300 Equivalent & Substitute Parts

Part Overview

The SMBJ300 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. The device features a 300V reverse standoff voltage, 510.3V maximum clamping voltage, and 600W peak pulse power rating in a DO-214AA (SMB) package. The SMBJ300 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	300	V
Voltage - Breakdown (Min)	317.7	V
Voltage - Clamping (Max) @ Ipp	510.3	V
Current - Peak Pulse (10/1000µs)	1.3	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	-
Operating Temperature	-65 to 150	°C (TJ)
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the SMBJ300 is determined by the following critical parameters:

Voltage - Reverse Standoff: 300V (exact match required)
Voltage - Clamping (Max) @ Ipp: 480–510V (acceptable range based on circuit protection requirements)
Current - Peak Pulse: 1.2–1.3A (acceptable range)
Power - Peak Pulse: 600W (exact match required)
Package / Case: DO-214AA, SMB (exact match required)
Type: Zener, Unidirectional (exact match required)

Substitute parts are grouped into three categories:

Direct Equivalents: Parts with clamping voltages between 480–510V, matching all electrical and mechanical specifications.

Upgrade Parts: Parts with lower clamping voltages (480–486V) that provide improved performance characteristics while maintaining functional compatibility.

Automotive-Grade Alternatives: Parts qualified to AEC-Q101 standards for applications requiring automotive-grade reliability.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Breakdown (Min) (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temperature (°C)	Product Status	Package
SMBJ300	Littelfuse Inc.	300	317.7	510.3	1.3	600	-65 to 150	Obsolete	DO-214AA, SMB
SMBJ300A	Good-Ark Semiconductor	300	335	486	1.3	600	-55 to 150	Active	DO-214AA, SMB
SMBJ300A-H	Bourns Inc.	300	335	486	1.3	600	-55 to 150	Active	DO-214AA, SMB
TV06B301J-G	Comchip Technology	300	335	486	1.23	600	Not specified	Active	DO-214AA, SMB
TV06B301J-HF	Comchip Technology	300	335	486	1.23	600	Not specified	Active	DO-214AA, SMB
P6SMB350A-M3/52	Vishay General Semiconductor - Diodes Division	300	333	482	1.24	600	-65 to 150	Active	DO-214AA, SMB
P6SMB350A-M3/5B	Vishay General Semiconductor - Diodes Division	300	333	482	1.24	600	-65 to 150	Active	DO-214AA, SMB
SMBJP6KE350A-TP	Micro Commercial Co	300	332	482	1.3	600	-55 to 175	Active	DO-214AA, SMB
SMBJP6KE350AL-TP	Micro Commercial Co	300	332	482	1.3	600	-55 to 175	Active	DO-214AA, SMB
ATV06B301J-HF	Comchip Technology	300	335	486	1.23	600	-55 to 150	Active	DO-214AA, SMB
P6SMB350A	Eaton - Electronics Division	300	332	482	1.3	600	-55 to 150	Active	DO-214AA, SMB

Engineering Selection Recommendations

For Direct Replacement (Active Status, Standard Grade):

SMBJ300A (Good-Ark Semiconductor) and SMBJ300A-H (Bourns Inc.) are the primary direct substitutes. Both maintain the 300V reverse standoff voltage, 1.3A peak pulse current, and 600W power rating. The clamping voltage of 486V is within acceptable tolerance for general-purpose protection applications. Both parts are in active production status with ROHS3 compliance.

For Extended Temperature Range Applications:

SMBJP6KE350A-TP and SMBJP6KE350AL-TP (Micro Commercial Co) extend the operating temperature range to -55°C to 175°C, providing enhanced thermal performance. These parts maintain 1.3A peak pulse current and 600W power rating with 482V clamping voltage.

For Automotive Applications:

ATV06B301J-HF (Comchip Technology) is qualified to AEC-Q101 automotive standards. This part maintains the 300V reverse standoff voltage, 1.23A peak pulse current, and 600W power rating with 486V clamping voltage. Use this part for automotive-grade circuit protection requirements.

For Wide Temperature Range with Extended Thermal Performance:

P6SMB350A-M3/52 and P6SMB350A-M3/5B (Vishay General Semiconductor - Diodes Division) maintain the original -65°C to 150°C operating temperature range with 482V clamping voltage and 1.24A peak pulse current. These parts are available in Cut Tape and Tape & Box packaging options.

Frequently Asked Questions (FAQ)

Q: Can SMBJ300A be used as a direct replacement for SMBJ300?

A: Yes. SMBJ300A maintains the critical electrical parameters: 300V reverse standoff voltage, 1.3A peak pulse current, and 600W power rating. The clamping voltage of 486V is within acceptable tolerance for general-purpose transient voltage suppression. Both parts use the DO-214AA (SMB) package.

Q: What is the difference between the clamping voltages in the substitute parts?

A: The original SMBJ300 specifies 510.3V maximum clamping voltage. Substitute parts range from 482V to 486V. Lower clamping voltages provide faster transient suppression and reduced voltage overshoot, which is beneficial for sensitive circuit protection. All values remain within the 300V reverse standoff voltage class.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant and suitable for applications requiring RoHS compliance.

Q: Which substitute part should be used for automotive applications?

A: ATV06B301J-HF is qualified to AEC-Q101 automotive standards. This part is specifically designed for automotive-grade circuit protection and reliability requirements.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in multiple packaging formats: Cut Tape (CT), Tape & Reel (TR), and Tape & Box (TB). All parts maintain the DO-214AA (SMB) surface-mount package for PCB compatibility.

Q: Can substitute parts with lower clamping voltages affect circuit performance?

A: Lower clamping voltages (482–486V versus 510.3V) result in faster transient suppression and reduced voltage overshoot. This is generally beneficial for protecting sensitive components. Verify that the lower clamping voltage is acceptable for your specific circuit protection requirements.

Q: Are there inventory considerations when selecting a substitute part?

A: Yes. Inventory levels vary by manufacturer and part number. SMBJ300A (Good-Ark Semiconductor) and P6SMB350A (Eaton - Electronics Division) have higher inventory availability (15,445 and 19,651 units respectively), making them suitable for high-volume production requirements.

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