SMCJ45C Transient Voltage Suppressor Diode - Equivalent & Substitute Parts

Part Overview

The SMCJ45C is a bidirectional Zener transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 45V reverse standoff voltage with a 76.34V maximum clamping voltage at peak pulse current of 20.6A, packaged in the DO-214AB (SMC) form factor. The SMCJ45C is classified as obsolete, necessitating identification of active equivalent and substitute parts that maintain electrical and mechanical compatibility for new designs or production continuity.

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)	20.6	A
Power - Peak Pulse	1500	W
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AB, SMC	—
Type	Zener	—
Bidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the SMCJ45C are classified into two functional groups based on electrical performance characteristics:

Group A: Direct Electrical Equivalents (SMCJ Series) Parts maintaining identical reverse standoff voltage (45V), breakdown voltage (50V minimum), clamping voltage (72.7V), and peak pulse current (20.6A) with 1500W peak pulse power rating. These parts are mechanically and electrically interchangeable with the original SMCJ45C in standard protection applications. Manufacturers include MDD, Diodes Incorporated, Micro Commercial Co, and Microchip Technology.

Group B: Enhanced Performance Alternatives (SMLJ Series) Parts with identical voltage specifications (45V standoff, 50V breakdown minimum, 72.7V clamping) but increased peak pulse current capability (41.2A) and doubled peak pulse power rating (3000W). These parts provide superior transient energy absorption while maintaining the same voltage protection envelope. Manufacturers include Bourns Inc., Micro Commercial Co, and Microchip Technology.

Group C: Variant Clamping Voltage (SMCJ45CE3/TR13) Part with identical voltage standoff and breakdown specifications but elevated clamping voltage (80.3V) and reduced peak pulse current (18.7A), maintaining 1500W peak pulse power. This variant is suitable for applications requiring higher voltage clamping margins.

Substitution eligibility is determined by: (1) matching reverse standoff voltage of 45V, (2) breakdown voltage minimum of 47.39V to 50V, (3) compatible package format (DO-214AB/SMC), (4) surface-mount technology, and (5) RoHS3 compliance.

Parameter Comparison

Part Number	Manufacturer	Standoff Voltage (V)	Breakdown Min (V)	Clamping Max (V)	Peak Pulse Current (A)	Peak Power (W)	Temp Range (°C)	Status
SMCJ45C	Littelfuse Inc.	45	47.39	76.34	20.6	1500	-55 to 150	Obsolete
SMCJ45CA	MDD	45	50	72.7	20.6	1500	-50 to 150	Active
SMCJ45CA-13-F	Diodes Incorporated	45	50	72.7	20.6	1500	-55 to 150	Active
SMCJ45CA-TP	Micro Commercial Co	45	50	72.7	20.6	1500	-55 to 175	Active
SMCJ45CAE3/TR13	Microchip Technology	45	50	72.7	20.6	1500	-65 to 150	Active
SMCJ45CE3/TR13	Microchip Technology	45	50	80.3	18.7	1500	-65 to 150	Active
SMLJ45CA	Bourns Inc.	45	50	72.7	41.2	3000	-55 to 150	Active
SMLJ45CA-TP	Micro Commercial Co	45	50	72.7	41.2	3000	-55 to 175	Active
SMLJ45CAE3/TR13	Microchip Technology	45	50	72.7	41.2	300	-55 to 150	Active

Engineering Selection Recommendations

For Direct Replacement (Equivalent Performance)

SMCJ45CA-13-F (Diodes Incorporated) is the primary recommendation for direct substitution. This part maintains identical electrical specifications to the SMCJ45C with matching temperature range (-55°C to 150°C), active product status, RoHS3 compliance, and standard Cut Tape & Digi-Reel packaging. Inventory availability is 1620 units.

SMCJ45CAE3/TR13 (Microchip Technology) provides an alternative with extended lower temperature rating (-65°C to 150°C) and active status. This part is suitable for applications requiring enhanced cold-temperature performance. Inventory availability is 713 units.

For Enhanced Protection Applications

SMLJ45CA (Bourns Inc.) and SMLJ45CA-TP (Micro Commercial Co) offer doubled peak pulse power capacity (3000W versus 1500W) with doubled peak pulse current (41.2A versus 20.6A) while maintaining identical voltage protection parameters. These parts are suitable for circuits requiring higher transient energy absorption. SMLJ45CA provides 13,067 units in stock; SMLJ45CA-TP provides 805 units.

For Extended Temperature Range

SMCJ45CA-TP (Micro Commercial Co) and SMLJ45CA-TP (Micro Commercial Co) both support extended upper operating temperature to 175°C, compared to the standard 150°C maximum. These variants are appropriate for high-temperature environments.

For Elevated Clamping Voltage Applications

SMCJ45CE3/TR13 (Microchip Technology) provides 80.3V maximum clamping voltage with reduced peak pulse current (18.7A). This variant is selected when circuit design requires higher voltage clamping margins within the 45V standoff voltage class.

All recommended substitutes maintain DO-214AB (SMC) package compatibility, surface-mount technology, RoHS3 compliance, and MSL 1 moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can SMCJ45CA parts directly replace SMCJ45C in existing designs?

A: Yes. SMCJ45CA variants from MDD, Diodes Incorporated, Micro Commercial Co, and Microchip Technology maintain identical reverse standoff voltage (45V), breakdown voltage (50V minimum), clamping voltage (72.7V), and peak pulse current (20.6A). All are packaged in DO-214AB (SMC) format with RoHS3 compliance. Electrical and mechanical compatibility is confirmed.

Q: What is the difference between SMCJ45CA and SMLJ45CA?

A: Both maintain identical voltage specifications (45V standoff, 50V breakdown, 72.7V clamping). The primary difference is peak pulse current and power rating: SMCJ45CA carries 20.6A at 1500W peak pulse power, while SMLJ45CA carries 41.2A at 3000W peak pulse power. SMLJ45CA is selected for applications requiring higher transient energy absorption capacity.

Q: Are temperature range differences significant for substitution?

A: Temperature range differences are application-dependent. The SMCJ45C operates -55°C to 150°C. Substitutes offer variations: SMCJ45CA (MDD) operates -50°C to 150°C; SMCJ45CA-13-F and SMCJ45CAE3/TR13 operate -55°C to 150°C; SMCJ45CA-TP operates -55°C to 175°C. Select based on circuit operating environment requirements.

Q: What does the clamping voltage specification mean for protection?

A: Clamping voltage is the maximum voltage across the TVS diode when conducting peak pulse current. The SMCJ45C clamps at 76.34V; most SMCJ45CA variants clamp at 72.7V; SMCJ45CE3/TR13 clamps at 80.3V. Lower clamping voltage provides tighter protection; higher clamping voltage allows greater voltage margin. Select based on protected circuit voltage tolerance.

Q: Is packaging format identical across all substitutes?

A: Yes. All substitute parts use DO-214AB (SMC) surface-mount package format, maintaining identical PCB footprint and reflow soldering compatibility with the original SMCJ45C design.

Q: What is the significance of product status (Active vs. Obsolete)?

A: Active status indicates current manufacturing and long-term availability. Obsolete status indicates discontinued production. All recommended substitutes carry Active status, ensuring supply chain continuity and future availability for production and repair applications.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All substitute parts listed maintain RoHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, matching the original SMCJ45C environmental and regulatory specifications.

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