SMDJ45 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMDJ45 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 45V reverse standoff voltage and provides peak pulse power dissipation of 3000W in a DO-214AB (SMC) package. The SMDJ45 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Multiple active alternatives from established manufacturers provide compatible electrical and mechanical characteristics suitable for direct replacement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	45	V
Voltage - Breakdown (Min)	47.39	V
Voltage - Clamping (Max) @ Ipp	76.34	V
Current - Peak Pulse (10/1000µs)	41.3	A
Power - Peak Pulse	3000	W
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
Operating Temperature Range	-65°C to 150°C	TJ
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution eligibility for the SMDJ45 is determined by the following critical parameters:

Voltage - Reverse Standoff (Typ): Must equal 45V
Unidirectional Channels: Must equal 1
Package / Case: Must be DO-214AB or SMC equivalent
Mounting Type: Must be Surface Mount
Type: Must be Zener diode
Applications: General Purpose

Substitute parts are grouped into two categories based on peak pulse current and power dissipation capacity:

Group A (Full Power Rating): Parts with 41.2A to 41.3A peak pulse current and 3000W peak pulse power. These provide direct electrical equivalence to the SMDJ45.

Group B (Reduced Power Rating): Parts with 20.6A to 20.63A peak pulse current and 1500W peak pulse power. These operate at half the power dissipation capacity and require circuit-level evaluation for compatibility.

All substitute parts maintain the same 45V reverse standoff voltage, 50V minimum breakdown voltage, and 72.7V maximum clamping voltage, ensuring functional compatibility in transient suppression applications.

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)	Operating Temp Range (°C)	Product Status
SMDJ45	Littelfuse Inc.	45	47.39	76.34	41.3	3000	-65 to 150	Obsolete
SMDJ45A	Alpha & Omega Semiconductor Inc.	45	50	72.7	41.3	3000	-55 to 150	Active
SMCJ45A	Meritek	45	50	72.7	20.63	1500	-55 to 150	Active
SMCJ45A-TP	Micro Commercial Co	45	50	72.7	20.6	1500	-55 to 175	Active
SMCJ45AE3/TR13	Microchip Technology	45	50	72.7	20.6	1500	-65 to 150	Active
SMLJ45A	Bourns Inc.	45	50	72.7	41.2	3000	-55 to 150	Active
SMLJ45A-TP	Micro Commercial Co	45	50	72.7	41.2	3000	-55 to 175	Active
SMLJ45AE3/TR13	Microchip Technology	45	50	72.7	41.2	3000	-55 to 150	Active

Engineering Selection Recommendations

Primary Substitutes (Full Electrical Equivalence)

SMDJ45A (Alpha & Omega Semiconductor Inc.), SMLJ45A (Bourns Inc.), SMLJ45A-TP (Micro Commercial Co), and SMLJ45AE3/TR13 (Microchip Technology) provide direct electrical replacement with 41.2A to 41.3A peak pulse current and 3000W power dissipation. All are active products with ROHS3 compliance. SMLJ45A-TP and SMLJ45AE3/TR13 support extended operating temperatures to 175°C and -65°C respectively, offering broader thermal operating ranges for specific applications.

Secondary Substitutes (Reduced Power Rating)

SMCJ45A (Meritek), SMCJ45A-TP (Micro Commercial Co), and SMCJ45AE3/TR13 (Microchip Technology) operate at 20.6A to 20.63A peak pulse current and 1500W power dissipation. These parts are suitable for applications where transient energy levels are lower than the original design specification. All maintain active product status and ROHS3 compliance.

All substitute parts are available in DO-214AB (SMC) surface-mount packaging and maintain the 45V reverse standoff voltage specification. Selection should prioritize active products with established supply availability and compliance certifications matching your application requirements.

Frequently Asked Questions (FAQ)

Q: Can SMCJ45A replace SMDJ45 directly in all applications?

A: SMCJ45A maintains the same 45V reverse standoff voltage and DO-214AB package but operates at half the peak pulse power (1500W vs. 3000W). Direct replacement is valid only if your circuit's transient energy dissipation does not exceed 1500W. Verify peak pulse current requirements in your application before substitution.

Q: What is the difference between SMDJ45A and SMLJ45A?

A: Both parts provide equivalent electrical performance with 41.2A to 41.3A peak pulse current and 3000W power dissipation. The primary difference is manufacturer: SMDJ45A is from Alpha & Omega Semiconductor Inc., while SMLJ45A is from Bourns Inc. Both are active products with identical voltage ratings and package specifications.

Q: Does packaging type (Tape & Reel vs. Bulk) affect electrical performance?

A: No. Packaging type (Tape & Reel or Bulk) is a logistics and handling specification only. Electrical characteristics, performance, and reliability remain identical regardless of packaging format. Selection should be based on your assembly process requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification, matching the original SMDJ45 specification. Verify REACH status with your supplier if regulatory compliance for specific markets is required.

Q: What is the operating temperature difference between substitutes?

A: The SMDJ45 operates from -65°C to 150°C. Substitute parts vary: most operate -55°C to 150°C, while SMCJ45A-TP and SMLJ45A-TP extend to 175°C. SMCJ45AE3/TR13 and SMLJ45AE3/TR13 maintain the -65°C lower limit. Select based on your thermal environment specifications.

Q: Can I use SMLJ45AE3/TR13 in place of SMDJ45 if my circuit requires -65°C operation?

A: Yes. SMLJ45AE3/TR13 maintains the -65°C lower operating temperature limit and provides full electrical equivalence with 41.2A peak pulse current and 3000W power dissipation. Verify tape & reel packaging compatibility with your assembly process.

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