SMBJ120 Equivalent & Substitute Parts

Part Overview

The SMBJ120 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse, designed for general-purpose overvoltage protection in surface-mount applications. The device features a 120V reverse standoff voltage rating and 600W peak pulse power handling capability in a DO-214AA (SMB) package. The original Littelfuse SMBJ120 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)	120	V
Voltage - Breakdown (Min)	126	V
Voltage - Clamping (Max) @ Ipp	202.65	V
Current - Peak Pulse (10/1000µs)	3.1	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

Substitute parts for the SMBJ120 are qualified based on the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 120V
Voltage - Breakdown (Min): 126V or higher
Current - Peak Pulse (10/1000µs): 3.1A
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Mounting Type: Surface Mount
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

All identified substitute parts maintain these core electrical specifications and package compatibility. Variations in clamping voltage (193V vs. 202.65V) and operating temperature ranges are within acceptable substitution parameters for general-purpose TVS applications, as the primary protection function is preserved.

Parameter Comparison

Parameter	SMBJ120 (Littelfuse)	SMBJ120A (MDD)	SMBJ120A-13-F (Diodes Inc.)	SMBJ120A-E3/52 (Vishay)	SMBJ120A-E3/5B (Vishay)
Manufacturer	Littelfuse	MDD	Diodes Incorporated	Vishay General Semiconductor	Vishay General Semiconductor
Product Status	Obsolete	Active	Active	Active	Active
Voltage - Reverse Standoff (Typ)	120V	120V	120V	120V	120V
Voltage - Breakdown (Min)	126V	133V	133V	133V	133V
Voltage - Clamping (Max) @ Ipp	202.65V	193V	193V	193V	193V
Current - Peak Pulse (10/1000µs)	3.1A	3.1A	3.1A	3.1A	3.1A
Power - Peak Pulse	600W	600W	600W	600W	600W
Operating Temperature Range	-65 to 150°C	-50 to 150°C	-55 to 150°C	-55 to 150°C	-55 to 150°C
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

All identified substitute parts are classified as active products with ROHS3 compliance and MSL 1 rating, ensuring regulatory compliance and manufacturing continuity. The SMBJ120A from MDD, SMBJ120A-13-F from Diodes Incorporated, and SMBJ120A-E3/52 and SMBJ120A-E3/5B from Vishay General Semiconductor maintain the core electrical specifications required for 120V TVS protection applications.

The primary electrical difference among substitutes is the clamping voltage specification: the original SMBJ120 specifies 202.65V maximum clamping, while all active substitutes specify 193V maximum clamping. This represents a 9.65V reduction in clamping voltage, which provides improved transient suppression performance. All substitutes maintain the 120V reverse standoff voltage and 3.1A peak pulse current ratings.

Operating temperature ranges vary slightly: the original part supports -65 to 150°C, while MDD SMBJ120A supports -50 to 150°C, and Diodes Incorporated and Vishay parts support -55 to 150°C. Selection should be based on specific application temperature requirements.

Frequently Asked Questions (FAQ)

Q: Can SMBJ120A parts from different manufacturers be used interchangeably?

A: Yes. SMBJ120A from MDD, SMBJ120A-13-F from Diodes Incorporated, and SMBJ120A-E3/52 and SMBJ120A-E3/5B from Vishay are electrically and mechanically equivalent. All maintain 120V reverse standoff voltage, 3.1A peak pulse current, 600W power rating, and DO-214AA (SMB) package compatibility. Selection may be based on availability, packaging format (cut tape, tape & reel), or supply chain preference.

Q: What is the significance of the lower clamping voltage in substitute parts?

A: The substitute parts specify 193V maximum clamping voltage compared to 202.65V in the original SMBJ120. This lower clamping voltage indicates improved transient suppression performance, as the device clamps overvoltage transients to a lower peak level, providing better circuit protection.

Q: Are there operating temperature considerations when selecting a substitute?

A: The original SMBJ120 supports -65 to 150°C junction temperature. MDD SMBJ120A supports -50 to 150°C, while Diodes Incorporated and Vishay parts support -55 to 150°C. Applications requiring operation below -50°C should verify compatibility with the selected substitute part's temperature range.

Q: What packaging options are available for substitute parts?

A: SMBJ120A-13-F from Diodes Incorporated is available in Tape & Reel (TR) packaging. SMBJ120A-E3/52 from Vishay is available in Cut Tape (CT) & Digi-Reel format. SMBJ120A-E3/5B from Vishay is available in Tape & Reel (TR). MDD SMBJ120A packaging format should be confirmed with the supplier. Selection depends on production volume and assembly process requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All identified substitute parts are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, meeting current regulatory requirements for electronic component manufacturing and assembly.

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