SMDJ8.5 Equivalent & Substitute Parts

Part Overview

The SMDJ8.5 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features an 8.5V reverse standoff voltage, 15.12V maximum clamping voltage, and 3000W peak pulse power rating in a DO-214AB (SMC) package. The product is currently obsolete, making equivalent and substitute parts necessary for ongoing design support and component procurement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	8.5	V
Voltage - Breakdown (Min)	8.93	V
Voltage - Clamping (Max) @ Ipp	15.12	V
Current - Peak Pulse (10/1000µs)	208.3	A
Power - Peak Pulse	3000	W
Package / Case	DO-214AB, SMC	—
Operating Temperature	-65 to 150	°C
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution for the SMDJ8.5 is determined by strict alignment of electrical and mechanical parameters. The critical substitution criteria are:

Primary Matching Parameters:

Voltage - Reverse Standoff: 8.5V (±tolerance)
Voltage - Clamping (Max) @ Ipp: 13.6V to 15.12V range
Current - Peak Pulse (10/1000µs): minimum 100A
Power - Peak Pulse: minimum 1500W
Package / Case: DO-214AB or SMC equivalent
Mounting Type: Surface Mount
Type: Zener, Unidirectional

Substitute parts are grouped into two categories based on power dissipation capability:

Category A (3000W Rating): SMDJ8.5A, SMLJ8.5A, SMLJ8.5A-TP, SMLJ8.5AE3/TR13 — Full electrical equivalence with original specifications.

Category B (1500W Rating): 1.5SMC10A-E3/57T, SMCJ8.5A, SMCJ8.5A-13-F, SMCJ8.5A-TP, SMCJ8.5AE3/TR13, SMCJ8V5A — Reduced power dissipation but maintained voltage and current parameters within acceptable operating ranges.

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)	Package	Product Status
SMDJ8.5	Littelfuse Inc.	8.5	15.12	208.3	3000	-65 to 150	DO-214AB, SMC	Obsolete
SMDJ8.5A	Alpha & Omega Semiconductor Inc.	8.5	14.4	208.4	3000	-55 to 150	DO-214AB, SMC	Active
1.5SMC10A-E3/57T	Vishay General Semiconductor - Diodes Division	8.55	14.5	103	1500	-65 to 150	DO-214AB, SMC	Active
SMCJ8.5A	EVVO Semi	8.5	14.4	104.2	1500	-55 to 150	DO-214AB, SMC	Active
SMCJ8.5A-13-F	Diodes Incorporated	8.5	14.4	104.2	1500	-55 to 150	DO-214AB, SMC	Active
SMCJ8.5A-TP	Micro Commercial Co	8.5	14.4	104.2	1500	-55 to 175	DO-214AB, SMC	Active
SMCJ8.5AE3/TR13	Microchip Technology	8.5	13.6	110.3	1500	-65 to 150	DO-214AB, SMC	Active
SMCJ8V5A	Fairchild Semiconductor	8.5	14.4	104.2	1500	—	DO-214AB, SMC	Active
SMLJ8.5A	Bourns Inc.	8.5	14.4	208.4	3000	-55 to 150	DO-214AB, SMC	Active
SMLJ8.5A-TP	Micro Commercial Co	8.5	14.4	208.4	3000	-55 to 175	DO-214AB, SMC	Active
SMLJ8.5AE3/TR13	Microchip Technology	8.5	14.4	208.4	300	-55 to 150	DO-214AB, SMC	Active

Engineering Selection Recommendations

Direct Equivalents (3000W Category): SMDJ8.5A, SMLJ8.5A, and SMLJ8.5A-TP provide full electrical and thermal equivalence to the original SMDJ8.5. All three are active products with ROHS3 compliance. SMLJ8.5A-TP offers the widest operating temperature range (-55°C to 175°C) and is recommended for applications requiring extended thermal performance.

Alternative Substitutes (1500W Category): SMCJ8.5A-TP and SMCJ8.5AE3/TR13 are suitable for applications where peak pulse power does not exceed 1500W. SMCJ8.5A-TP supports the highest operating temperature (175°C) among 1500W options. SMCJ8.5AE3/TR13 maintains the original -65°C lower temperature limit, matching the SMDJ8.5 specification.

Compliance Considerations: All substitute parts listed are ROHS3 compliant. SMLJ8.5A carries REACH Affected status; all other substitutes are REACH Unaffected or REACH Compliant. Verify compliance requirements for your specific application before final selection.

Frequently Asked Questions (FAQ)

Q: Can I use a 1500W-rated substitute in place of the original 3000W SMDJ8.5? A: Yes, provided your circuit's peak pulse power requirement does not exceed 1500W. The voltage and current parameters remain compatible. Verify thermal dissipation requirements in your application.

Q: What is the difference between SMCJ and SMLJ series substitutes? A: SMLJ series parts maintain the original 3000W peak pulse power rating and 208.3A peak current specification. SMCJ series parts reduce power to 1500W and peak current to approximately 104A. Select based on your application's power dissipation requirements.

Q: Are all substitute parts available in the same DO-214AB package? A: Yes. All listed substitutes use DO-214AB (SMC) surface-mount packaging, ensuring mechanical and footprint compatibility with the original SMDJ8.5 design.

Q: Which substitute offers the best temperature range coverage? A: SMLJ8.5A-TP and SMCJ8.5A-TP both support -55°C to 175°C operating temperature, exceeding the original -65°C to 150°C range. For applications requiring the full -65°C lower limit, select SMCJ8.5AE3/TR13 or 1.5SMC10A-E3/57T.

Q: Is the voltage clamping difference between 13.6V and 15.12V significant? A: The clamping voltage variation (13.6V to 15.12V) falls within acceptable TVS diode tolerance ranges for 8.5V standoff applications. Verify your circuit's maximum allowable clamping voltage before selection. Lower clamping voltages provide tighter protection margins.

Q: What packaging options are available for these substitutes? A: Substitute parts are available in Tape & Reel (TR), Cut Tape (CT), Bulk, and Digi-Reel packaging formats. Verify your procurement and assembly requirements when selecting specific part variants.

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