SMCJ85 Equivalent & Substitute Parts

Part Overview

The Littelfuse SMCJ85 is a transient voltage suppressor (TVS) diode designed for general-purpose overvoltage protection in surface-mount applications. This unidirectional Zener diode operates at 85V reverse standoff with a 143.85V maximum clamping voltage and 11A peak pulse current capability in a DO-214AB (SMC) package. The SMCJ85 is classified as obsolete, necessitating identification of active equivalent and substitute parts that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	85	V
Voltage - Breakdown (Min)	89.28	V
Voltage - Clamping (Max) @ Ipp	143.85	V
Current - Peak Pulse (10/1000µs)	11	A
Power - Peak Pulse	1500	W
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
Operating Temperature Range	-55 to 150	°C
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the SMCJ85 is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 85V (exact match required)
Voltage - Clamping (Max) @ Ipp: 137V to 151V (acceptable range based on provided data)
Current - Peak Pulse (10/1000µs): 10.4A to 11A (acceptable range for SMCJ series); 20.8A (acceptable for SMLJ series with higher power rating)
Package / Case: DO-214AB, SMC (exact match required)
Mounting Type: Surface Mount (exact match required)
Type: Zener, Unidirectional (exact match required)

Substitute Categories:

Category 1: Direct Electrical Equivalents (SMCJ Series) Parts maintaining 11A peak pulse current, 1500W power rating, and 137V clamping voltage:

SMCJ85A (MDD, Micro Commercial Co)
SMCJ85A-13-F (Diodes Incorporated)
SMCJ85A-TP (Micro Commercial Co)
SMCJ85AE3/TR13 (Microchip Technology)

Category 2: Higher Power Rating Equivalents (SMLJ Series) Parts with increased peak pulse current (20.8A) and 3000W power rating, maintaining 85V standoff and 137V clamping:

SMLJ85A (Bourns Inc.)
SMLJ85A-TP (Micro Commercial Co)
SMLJ85AE3/TR13 (Microchip Technology)

Category 3: Clamping Voltage Variant Part with higher clamping voltage (151V) while maintaining other electrical parameters:

SMCJ85E3/TR13 (Microchip Technology)

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)	Product Status	Package
SMCJ85	Littelfuse	85	143.85	11	1500	-55 to 150	Obsolete	DO-214AB, SMC
SMCJ85A	MDD	85	137	11	1500	-50 to 150	Active	DO-214AB, SMC
SMCJ85A-13-F	Diodes Incorporated	85	137	10.4	1500	-55 to 150	Active	DO-214AB, SMC
SMCJ85A-TP	Micro Commercial Co	85	137	11	1500	-55 to 175	Active	DO-214AB, SMC
SMCJ85AE3/TR13	Microchip Technology	85	137	10.4	1500	-65 to 150	Active	DO-214AB, SMC
SMCJ85E3/TR13	Microchip Technology	85	151	9.9	1500	-65 to 150	Active	DO-214AB, SMC
SMLJ85A	Bourns Inc.	85	137	20.8	3000	-55 to 150	Active	DO-214AB, SMC
SMLJ85A-TP	Micro Commercial Co	85	137	20.8	3000	-55 to 175	Active	DO-214AB, SMC
SMLJ85AE3/TR13	Microchip Technology	85	137	20.8	300	-55 to 150	Active	DO-214AB, SMC

Engineering Selection Recommendations

For Direct Replacement (SMCJ Series - 11A, 1500W):

SMCJ85A-TP (Micro Commercial Co) is the primary recommended substitute. This part maintains identical electrical specifications to the original SMCJ85, offers active product status with established supply chain availability (3397 pcs in stock), and extends the operating temperature range to 175°C. RoHS3 compliance and REACH unaffected status confirm regulatory alignment.

SMCJ85AE3/TR13 (Microchip Technology) provides an alternative with extended lower temperature operation (-65°C) and active status, suitable for applications requiring broader thermal performance. Peak pulse current is rated at 10.4A, which remains within acceptable tolerance for the 85V standoff class.

For Higher Power Applications (SMLJ Series - 20.8A, 3000W):

SMLJ85A-TP (Micro Commercial Co) and SMLJ85A (Bourns Inc.) both provide doubled peak pulse current and doubled power dissipation capability while maintaining the same 85V standoff and 137V clamping voltage. These are suitable for applications requiring enhanced transient energy absorption. SMLJ85A-TP offers extended temperature range to 175°C.

For Clamping Voltage Variant:

SMCJ85E3/TR13 (Microchip Technology) provides 151V clamping voltage with 9.9A peak pulse current. This variant is appropriate only when circuit design specifically requires higher clamping voltage tolerance.

All recommended substitutes carry RoHS3 compliance and are packaged in DO-214AB (SMC) surface-mount format, ensuring mechanical and environmental compatibility with existing PCB designs.

Frequently Asked Questions (FAQ)

Q: Can SMCJ85A directly replace SMCJ85 in existing designs?

A: Yes. SMCJ85A maintains the critical electrical parameters: 85V reverse standoff, 137V clamping voltage (within acceptable tolerance of the original 143.85V), 11A peak pulse current, and 1500W power rating. The DO-214AB package and surface-mount configuration are identical. Verify that the lower clamping voltage (137V vs. 143.85V) is acceptable for your specific circuit protection requirements.

Q: What is the difference between SMCJ85A and SMLJ85A?

A: Both maintain 85V standoff and 137V clamping voltage in DO-214AB packages. The primary difference is peak pulse current and power dissipation: SMCJ85A is rated for 11A and 1500W, while SMLJ85A is rated for 20.8A and 3000W. Select SMLJ85A when the circuit experiences higher transient energy that exceeds the 1500W capability of SMCJ85A.

Q: Are there temperature range differences between substitutes?

A: Yes. The original SMCJ85 operates from -55°C to 150°C. SMCJ85A-TP and SMLJ85A-TP extend the upper limit to 175°C. SMCJ85AE3/TR13 and SMCJ85E3/TR13 extend the lower limit to -65°C. Select based on your application's thermal requirements.

Q: Does packaging differ between SMCJ and SMLJ series?

A: No. Both SMCJ and SMLJ series use the DO-214AB (SMC) surface-mount package. The physical footprint and PCB layout are identical. The series designation reflects internal die size and current rating, not package format.

Q: What does "Tape & Reel (TR)" packaging mean?

A: Tape & Reel packaging indicates the parts are supplied on continuous carrier tape wound on reels, suitable for automated pick-and-place assembly. This is standard for high-volume production. Verify your assembly equipment compatibility with SMC package specifications.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All recommended substitutes carry RoHS3 compliance certification, confirming restriction of hazardous substances in accordance with current environmental regulations.

Q: Can I use SMCJ85E3/TR13 with 151V clamping instead of 137V?

A: SMCJ85E3/TR13 is a valid substitute only if your circuit design specifically tolerates or requires the higher 151V clamping voltage. If the original design was optimized for 143.85V clamping, the 151V variant may alter circuit protection characteristics. Consult your circuit protection analysis before substitution.

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