SMDJ30 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMDJ30 is a unidirectional transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. Specified with a 30V reverse standoff voltage, 50.82V maximum clamping voltage, and 62A peak pulse current capability, the SMDJ30 operates across -65°C to 150°C and is housed in a DO-214AB (SMC) package. The product is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for ongoing design support and production requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	30	V
Voltage - Breakdown (Min)	31.55	V
Voltage - Clamping (Max) @ Ipp	50.82	V
Current - Peak Pulse (10/1000µs)	62	A
Power - Peak Pulse	3000	W
Operating Temperature Range	-65 to 150	°C
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SMDJ30 is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 30V (exact match required)
Voltage - Clamping (Max) @ Ipp: 48.4V to 50.82V (acceptable range for protection circuit compatibility)
Current - Peak Pulse (10/1000µs): 62A minimum (equal or greater capability)
Power - Peak Pulse: 3000W minimum (equal or greater capability)
Package / Case: DO-214AB or SMC (mechanical and thermal compatibility)
Mounting Type: Surface Mount (PCB assembly process compatibility)
RoHS Status: ROHS3 Compliant (regulatory requirement)

Secondary Consideration:

Product Status: Active preferred (ensures long-term availability and supply chain stability)

Substitute parts are grouped into two categories based on peak pulse current and power dissipation capacity: full-specification equivalents (62A / 3000W) and reduced-specification alternatives (31A / 1500W). Full-specification equivalents provide direct functional replacement. Reduced-specification alternatives are suitable only for applications where peak pulse current does not exceed 31A and peak pulse power does not exceed 1500W.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temperature (°C)	Package	Product Status
SMDJ30	Littelfuse Inc.	30	50.82	62	3000	-65 to 150	DO-214AB	Obsolete
SMDJ30A	Alpha & Omega Semiconductor Inc.	30	48.4	62	3000	-55 to 150	DO-214AB	Active
3.0SMCJ30A-13	Diodes Incorporated	30	48.4	62	3000	-55 to 175	SMC	Active
SMCJ30A	MDD	30	48.4	31	1500	-50 to 150	SMC/DO-214AB	Active
SMCJ30A-TP	Micro Commercial Co	30	48.4	31	1500	-55 to 175	SMC	Active
SMCJLCE30AE3/TR13	Microsemi Corporation	30	48.4	31	1500	-65 to 150	DO-214AB	Active
SMLJ30A	Bourns Inc.	30	48.4	62	3000	-55 to 150	SMC	Active
SMLJ30A-TP	Micro Commercial Co	30	48.4	62	3000	-55 to 175	SMC	Active
SMLJ30AE3/TR13	Microchip Technology	30	48.4	62	3000	-55 to 150	DO-214AB	Active

Engineering Selection Recommendations

Full-Specification Equivalents (62A / 3000W):

For applications requiring the complete electrical performance of the SMDJ30, the following active parts provide direct substitution:

SMDJ30A (Alpha & Omega Semiconductor Inc.): Maintains 62A peak pulse current and 3000W power dissipation. Operating temperature range -55°C to 150°C is narrower than the original -65°C to 150°C; suitable for applications not requiring sub-55°C operation.
3.0SMCJ30A-13 (Diodes Incorporated): Delivers 62A peak pulse current and 3000W power dissipation with extended upper temperature rating to 175°C. Recommended for applications requiring elevated temperature performance.
SMLJ30A (Bourns Inc.): Provides 62A peak pulse current and 3000W power dissipation. Operating temperature -55°C to 150°C. REACH Affected status requires supply chain verification for regulated substance compliance.
SMLJ30A-TP (Micro Commercial Co): Delivers 62A peak pulse current and 3000W power dissipation with extended upper temperature rating to 175°C. Tape & Reel packaging supports automated assembly.
SMLJ30AE3/TR13 (Microchip Technology): Provides 62A peak pulse current and 3000W power dissipation. Tape & Reel packaging supports high-volume production.

Reduced-Specification Alternatives (31A / 1500W):

For applications where peak pulse current does not exceed 31A and peak pulse power does not exceed 1500W:

SMCJ30A (MDD): Rated 31A peak pulse current and 1500W power dissipation. Operating temperature -50°C to 150°C. Largest inventory availability (22,928 pcs).
SMCJ30A-TP (Micro Commercial Co): Rated 31A peak pulse current and 1500W power dissipation with extended upper temperature rating to 175°C. Tape & Reel packaging.
SMCJLCE30AE3/TR13 (Microsemi Corporation): Rated 31A peak pulse current and 1500W power dissipation. Operating temperature -65°C to 150°C matches original specification. Lowest capacitance (100pF @ 1MHz) suitable for high-frequency applications.

All recommended substitutes are ROHS3 compliant and maintain the 30V reverse standoff voltage and DO-214AB/SMC package compatibility required for mechanical and thermal integration.

Frequently Asked Questions (FAQ)

Q: Can SMCJ30A (31A / 1500W) be used as a direct replacement for SMDJ30 (62A / 3000W)?

A: SMCJ30A is a functional substitute only for applications where peak pulse current remains below 31A and peak pulse power remains below 1500W. If the original circuit design requires 62A peak pulse current or 3000W power dissipation capability, SMCJ30A will not provide adequate protection and may fail under transient overvoltage events. Verify application requirements before substitution.

Q: What is the difference between DO-214AB and SMC package designations?

A: DO-214AB and SMC refer to the same physical package form factor used for surface-mount diodes. Both designations are interchangeable for PCB assembly and thermal performance. Package designation differences reflect manufacturer nomenclature conventions and do not affect electrical or mechanical compatibility.

Q: Why does the SMDJ30A have a lower clamping voltage (48.4V) than the original SMDJ30 (50.82V)?

A: Clamping voltage variation within the 30V reverse standoff class is a normal manufacturing tolerance. The 48.4V clamping voltage of substitute parts remains within acceptable limits for general-purpose transient voltage suppression and does not compromise circuit protection. Both values meet the functional requirement of limiting transient overvoltage to safe levels.

Q: Are all substitute parts suitable for high-volume production?

A: Substitute parts with Tape & Reel (TR) packaging designation (SMDJ30A, 3.0SMCJ30A-13, SMCJ30A-TP, SMLJ30A-TP, SMLJ30AE3/TR13, SMCJLCE30AE3/TR13) are optimized for automated pick-and-place assembly. Parts without specified packaging may require manual handling or custom reel preparation. Verify packaging format compatibility with production equipment before design release.

Q: What is the significance of REACH Affected status for SMLJ30A?

A: REACH Affected status indicates the part may contain substances subject to European Union chemical regulations. Supply chain verification is required to confirm compliance with specific application requirements. Contact the manufacturer or authorized distributor for current REACH documentation and substance declarations.

Q: Which substitute provides the widest operating temperature range?

A: SMCJLCE30AE3/TR13 (Microsemi Corporation) and SMLJ30A-TP (Micro Commercial Co) both extend the upper operating temperature to 175°C. SMCJLCE30AE3/TR13 additionally maintains the lower temperature limit of -65°C, matching the original SMDJ30 specification. Select based on specific application temperature requirements.

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