SMCJ18C Equivalent & Substitute Parts

Part Overview

The SMCJ18C is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., rated for 18V reverse standoff with a 30.66V maximum clamping voltage at peak pulse current of 51.4A. The device is packaged in DO-214AB (SMC) surface mount configuration and is designed for general-purpose transient voltage suppression applications. The SMCJ18C is classified as obsolete, necessitating identification of active equivalent and substitute parts that maintain electrical and mechanical compatibility within specified parameter tolerances.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	18	V
Voltage - Breakdown (Min)	18.95	V
Voltage - Clamping (Max) @ Ipp	30.66	V
Current - Peak Pulse (10/1000µs)	51.4	A
Power - Peak Pulse	1500	W
Mounting Type	Surface Mount	—
Package / Case	DO-214AB, SMC	—
Operating Temperature Range	-55 to 150	°C
Type	Zener	—
Bidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the SMCJ18C are grouped based on the following electrical and mechanical criteria:

Primary Substitution Parameters:

Voltage - Reverse Standoff (Typ): 18V
Voltage - Breakdown (Min): 18.95V to 20V range
Mounting Type: Surface Mount
Package / Case: DO-214AB, SMC
Type: Zener, Bidirectional, Single Channel
RoHS Status: ROHS3 Compliant
MSL: 1 (Unlimited)

Acceptable Variation Ranges:

Voltage - Clamping (Max) @ Ipp: 29.2V to 39.3V (within transient suppression design margins)
Current - Peak Pulse (10/1000µs): 51.4A to 254A (higher current ratings provide enhanced protection capability)
Power - Peak Pulse: 1500W to 3000W (higher power ratings maintain thermal performance)
Operating Temperature: -55°C to -65°C minimum; 150°C to 175°C maximum (extended ranges acceptable)

Substitute parts meeting these criteria are functionally equivalent for general-purpose transient voltage suppression applications with identical reverse standoff voltage and compatible package specifications.

Parameter Comparison

Part Number	Manufacturer	VR (Typ) V	VBR (Min) V	VC (Max) @ Ipp V	Ipp A	PPP W	Temp Range °C	Status
SMCJ18C	Littelfuse Inc.	18	18.95	30.66	51.4	1500	-55 to 150	Obsolete
SMCJ18CA	EVVO Semi	18	20	29.2	51.4	1500	-55 to 150	Active
SMCJ18CA-13-F	Diodes Incorporated	18	20	29.2	51.4	1500	-55 to 150	Active
SMCJ18CA-TP	Micro Commercial Co	18	20	29.2	51.4	1500	-55 to 175	Active
SMCJ18CA-TR	STMicroelectronics	18	20	39.3	254	1500	-55 to 150	Active
SMCJ18CAE3/TR13	Microchip Technology	18	20	29.2	51.4	1500	-65 to 150	Active
SMCJ18CE3/TR13	Microchip Technology	18	20	32.2	46.6	1500	-65 to 150	Active
SMLJ18CA	Bourns Inc.	18	20	29.2	102.8	3000	-55 to 150	Active
SMLJ18CA-TP	Micro Commercial Co	18	20	29.2	102.8	3000	-55 to 175	Active

Engineering Selection Recommendations

Direct Electrical Equivalents (Identical Ipp and PPP): SMCJ18CA (EVVO Semi), SMCJ18CA-13-F (Diodes Incorporated), SMCJ18CA-TP (Micro Commercial Co), SMCJ18CAE3/TR13 (Microchip Technology), and SMCJ18CE3/TR13 (Microchip Technology) provide direct functional equivalence with the SMCJ18C. All are ROHS3 compliant with MSL 1 rating. Selection among these parts depends on packaging format availability (Cut Tape, Digi-Reel, or Tape & Reel) and inventory requirements.

Enhanced Performance Alternatives: SMCJ18CA-TR (STMicroelectronics) offers increased peak pulse current (254A at 8/20µs) and higher clamping voltage (39.3V), suitable for applications requiring enhanced transient suppression margin. SMLJ18CA (Bourns Inc.) and SMLJ18CA-TP (Micro Commercial Co) provide doubled peak pulse current (102.8A) and doubled peak pulse power (3000W), appropriate for high-energy transient environments.

Temperature Range Considerations: SMCJ18CA-TP and SMLJ18CA-TP extend the maximum operating temperature to 175°C, compared to 150°C for most alternatives. SMCJ18CAE3/TR13 and SMCJ18CE3/TR13 extend the minimum operating temperature to -65°C.

All substitute parts maintain the 18V reverse standoff voltage, DO-214AB (SMC) package configuration, and single-channel bidirectional topology required for direct replacement of the SMCJ18C.

Frequently Asked Questions (FAQ)

Q: Can SMLJ18CA replace SMCJ18C directly? A: SMLJ18CA is electrically compatible with identical 18V reverse standoff voltage and 29.2V clamping voltage. However, it provides doubled peak pulse current (102.8A vs. 51.4A) and doubled peak pulse power (3000W vs. 1500W). This higher rating does not prevent direct substitution but represents enhanced protection capability. Verify circuit design does not depend on the lower current rating of the original part.

Q: What is the difference between SMCJ18CA and SMCJ18CA-TR? A: Both maintain 18V reverse standoff voltage and identical package configuration. SMCJ18CA-TR (STMicroelectronics) specifies peak pulse current of 254A at 8/20µs pulse width and 39.3V clamping voltage, compared to SMCJ18CA at 51.4A (10/1000µs) and 29.2V. The different pulse width specification reflects manufacturer test methodology. SMCJ18CA-TR provides higher transient suppression capability.

Q: Are all substitute parts ROHS3 compliant? A: All listed substitute parts are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the original SMCJ18C specification.

Q: Does packaging format affect electrical performance? A: No. Cut Tape (CT), Digi-Reel, and Tape & Reel (TR) packaging formats are logistics variants only. Electrical specifications remain identical across packaging options for the same part number.

Q: Which substitute provides the closest electrical match to SMCJ18C? A: SMCJ18CA (EVVO Semi), SMCJ18CA-13-F (Diodes Incorporated), and SMCJ18CAE3/TR13 (Microchip Technology) provide the closest match with identical 51.4A peak pulse current and 29.2V clamping voltage. All are active products with full ROHS3 compliance.

Q: Can I use SMCJ18CE3/TR13 instead of SMCJ18CAE3/TR13? A: SMCJ18CE3/TR13 maintains the 18V reverse standoff voltage but specifies 32.2V clamping voltage and 46.6A peak pulse current. This represents a different electrical characteristic within the 18V family. Substitution is acceptable only if circuit design tolerates the modified clamping voltage and reduced current rating.

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