SMCJ45 Transient Voltage Suppressor (TVS) Diode – Equivalent & Substitute Parts

Part Overview

The SMCJ45 is a unidirectional Zener-type transient voltage suppressor manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 45V reverse standoff voltage with a maximum clamping voltage of 76.34V at peak pulse current, housed in a DO-214AB (SMC) package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for ongoing production and field replacement requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	SMCJ45
Manufacturer	Littelfuse Inc.
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Unidirectional Channels	1
Voltage – Reverse Standoff (Typ)	45V
Voltage – Breakdown (Min)	47.39V
Voltage – Clamping (Max) @ Ipp	76.34V
Current – Peak Pulse (10/1000µs)	20.6A
Power – Peak Pulse	1500W
Operating Temperature	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount
Package / Case	DO-214AB, SMC
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the SMCJ45 is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

Voltage – Reverse Standoff (Typ): 45V
Package / Case: DO-214AB, SMC
Mounting Type: Surface Mount
Unidirectional Channels: 1
Type: Zener
Power – Peak Pulse: 1500W
Operating Temperature Range: -55°C to 150°C minimum

Acceptable Variation Range:

Voltage – Clamping (Max) @ Ipp: 72.7V to 80.3V (within transient suppression design tolerance)
Current – Peak Pulse (10/1000µs): 18.7A to 20.63A (within pulse handling capability)
Voltage – Breakdown (Min): 50V (acceptable within 45V standoff specification)

Substitute parts are grouped into two categories: Direct Equivalents (matching clamping voltage 72.7V and peak pulse current 20.6A–20.63A) and Upgrade Alternatives (extended temperature range or modified electrical characteristics). All listed substitutes maintain DO-214AB package compatibility, ROHS3 compliance, and MSL 1 rating.

Parameter Comparison

Part Number	Manufacturer	Voltage – Reverse Standoff (Typ)	Voltage – Breakdown (Min)	Voltage – Clamping (Max) @ Ipp	Current – Peak Pulse (10/1000µs)	Power – Peak Pulse	Operating Temperature	Product Status	Package / Case
SMCJ45	Littelfuse Inc.	45V	47.39V	76.34V	20.6A	1500W	-55°C ~ 150°C	Obsolete	DO-214AB, SMC
SMCJ45A	Meritek	45V	50V	72.7V	20.63A	1500W	-55°C ~ 150°C	Active	DO-214AB (SMC)
SMCJ45A-E3/57T	Vishay General Semiconductor – Diodes Division	45V	50V	72.7V	20.6A	1500W	-55°C ~ 150°C	Active	DO-214AB, SMC
SMCJ45A-E3/9AT	Vishay General Semiconductor – Diodes Division	45V	50V	72.7V	20.6A	1500W	-55°C ~ 150°C	Active	DO-214AB, SMC
SMCJ45A-M3/57T	Vishay General Semiconductor – Diodes Division	45V	50V	72.7V	20.6A	1500W	-55°C ~ 150°C	Active	DO-214AB, SMC
SMCJ45A-M3/9AT	Vishay General Semiconductor – Diodes Division	45V	50V	72.7V	20.6A	1500W	-55°C ~ 150°C	Active	DO-214AB, SMC
TV15C450J-HF	Comchip Technology	45V	50V	72.7V	20.63A	1500W	-55°C ~ 150°C	Active	DO-214AB, SMC
SMCJ45AE3/TR13	Microchip Technology	45V	50V	72.7V	20.6A	1500W	-65°C ~ 150°C	Active	DO-214AB, SMC
SMCJ45E3/TR13	Microchip Technology	45V	50V	80.3V	18.7A	1500W	-65°C ~ 150°C	Active	DO-214AB, SMC

Engineering Selection Recommendations

Direct Equivalents (Preferred for Drop-In Replacement): SMCJ45A (Meritek), SMCJ45A-E3/57T, SMCJ45A-E3/9AT, SMCJ45A-M3/57T, SMCJ45A-M3/9AT (Vishay), and TV15C450J-HF (Comchip) are functionally equivalent to the obsolete SMCJ45. All maintain 45V reverse standoff voltage, 72.7V clamping voltage, 20.6A–20.63A peak pulse current, and 1500W peak pulse power within the -55°C to 150°C operating range. All are ROHS3 compliant with MSL 1 rating and housed in DO-214AB (SMC) packages. These parts are currently in active production status with substantial inventory availability.

Upgrade Alternatives (Extended Temperature Range): SMCJ45AE3/TR13 (Microchip) extends the lower operating temperature limit to -65°C while maintaining all other electrical specifications. SMCJ45E3/TR13 (Microchip) provides an extended temperature range (-65°C to 150°C) with a higher clamping voltage of 80.3V and reduced peak pulse current of 18.7A. The SMCJ45E3/TR13 is suitable only when the higher clamping voltage and lower peak pulse current are acceptable within the circuit design.

Selection Basis: All recommended substitutes are active products with ROHS3 compliance and MSL 1 moisture sensitivity rating, ensuring regulatory alignment and long-term supply continuity. Packaging variants (Cut Tape, Tape & Reel) are available across manufacturers to accommodate different procurement and assembly workflows.

Frequently Asked Questions (FAQ)

Q: Can SMCJ45A from Meritek directly replace the obsolete Littelfuse SMCJ45? A: Yes. Both components share identical reverse standoff voltage (45V), package type (DO-214AB, SMC), mounting configuration (surface mount), and operating temperature range (-55°C to 150°C). The clamping voltage difference (72.7V vs. 76.34V) and peak pulse current (20.63A vs. 20.6A) fall within acceptable transient suppression design tolerances.

Q: What is the difference between SMCJ45A-E3/57T and SMCJ45A-M3/57T? A: Both parts are manufactured by Vishay and share identical electrical specifications (45V standoff, 72.7V clamping, 20.6A peak pulse). The suffix designations indicate different packaging and tape configurations. The "-E3/57T" variant uses Cut Tape (CT) & Digi-Reel packaging, while "-M3/57T" uses standard Tape & Reel (TR). Selection depends on assembly line requirements and procurement preferences.

Q: Is the Comchip TV15C450J-HF compatible with the SMCJ45? A: Yes. The TV15C450J-HF maintains the same 45V reverse standoff voltage, 72.7V clamping voltage, 20.63A peak pulse current, 1500W peak pulse power, and DO-214AB (SMC) package. It is ROHS3 compliant with MSL 1 rating and currently in active production.

Q: When should I use SMCJ45E3/TR13 instead of SMCJ45A? A: SMCJ45E3/TR13 is selected only when the extended lower operating temperature (-65°C vs. -55°C) is required. This part has a higher clamping voltage (80.3V) and lower peak pulse current (18.7A). Use only if circuit design specifications explicitly allow these electrical parameter changes.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All listed substitute parts carry ROHS3 compliance certification and MSL 1 (unlimited moisture sensitivity) rating, matching the original SMCJ45 specifications.

Q: What packaging options are available for SMCJ45A variants? A: Vishay offers SMCJ45A in multiple packaging configurations: Cut Tape (CT) & Digi-Reel (E3/57T variant) and standard Tape & Reel (M3/57T and M3/9AT variants). Meritek and Comchip supply standard Tape & Reel packaging. Selection is based on assembly equipment compatibility and procurement workflow.

Q: Can I mix different manufacturers' SMCJ45A parts in the same production run? A: Yes. All SMCJ45A variants from Meritek, Vishay, and Comchip meet identical electrical and mechanical specifications for the 45V/72.7V rating. Substitution between manufacturers is electrically valid. Verify procurement and supply chain documentation for traceability requirements.

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