SMBJ85C Transient Voltage Suppressor Diode - Equivalent & Substitute Parts

Part Overview

The SMBJ85C is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features an 85V reverse standoff voltage with a 143.85V maximum clamping voltage and 4.4A peak pulse current capability in a DO-214AA (SMB) package. The SMBJ85C is classified as obsolete, making identification of functionally equivalent active alternatives necessary for new designs and ongoing production support.

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)	4.4	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	-
Mounting Type	Surface Mount	-
Operating Temperature	-65 to 150	°C (TJ)
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the SMBJ85C is determined by strict alignment of electrical and mechanical parameters. The following criteria establish functional equivalence:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 85V (exact match required)
Voltage - Clamping (Max) @ Ipp: 137V to 143.85V (acceptable range)
Current - Peak Pulse (10/1000µs): 4.38A to 4.4A (acceptable range)
Power - Peak Pulse: 600W (exact match)
Package / Case: DO-214AA, SMB (exact match required)
Mounting Type: Surface Mount (exact match required)
Type: Zener (exact match required)
Bidirectional Channels: 1 (exact match required)

All substitute parts listed maintain these core electrical specifications within acceptable tolerances and share identical mechanical packaging. Compliance certifications (RoHS3, REACH) are verified for each substitute.

Parameter Comparison

Part Number	Manufacturer	VWM (V)	VBR Min (V)	VC Max @ Ipp (V)	Ipp (A)	Power (W)	Package	Status	Temp Range (°C)
SMBJ85C	Littelfuse Inc.	85	89.28	143.85	4.4	600	DO-214AA, SMB	Obsolete	-65 to 150
SMBJ85CA	Meritek	85	94.4	137	4.38	600	DO-214AA, SMB	Active	-55 to 150
SMBJ85CA-13-F	Diodes Incorporated	85	94.4	137	4.4	600	DO-214AA, SMB	Active	-55 to 150
SMBJ85CA-M3/52	Vishay General Semiconductor - Diodes Division	85	94.4	137	4.4	600	DO-214AA, SMB	Active	-55 to 150
SMBJ85CA-M3/5B	Vishay General Semiconductor - Diodes Division	85	94.4	137	4.4	600	DO-214AA, SMB	Active	-55 to 150
SMBJ85CA-TP	Micro Commercial Co	85	94.4	137	4.4	600	DO-214AA, SMB	Active	-55 to 175
TV06B850JB-G	Comchip Technology	85	94.4	137	4.38	600	DO-214AA, SMB	Active	Not specified
TV06B850JB-HF	Comchip Technology	85	94.4	137	4.38	600	DO-214AA, SMB	Active	Not specified

Engineering Selection Recommendations

All listed substitute parts are classified as Active products, ensuring ongoing availability and manufacturing support. Each substitute maintains ROHS3 compliance and meets REACH requirements, satisfying modern regulatory standards for electronic components.

The clamping voltage differential between the SMBJ85C (143.85V maximum) and substitute parts (137V maximum) falls within acceptable engineering tolerance for general-purpose transient suppression applications. The reverse standoff voltage of 85V is maintained across all substitutes, ensuring consistent circuit protection thresholds.

Peak pulse current specifications range from 4.38A to 4.4A across all substitutes, representing negligible variation in transient energy absorption capability. All parts share identical DO-214AA (SMB) surface-mount packaging, enabling direct PCB layout compatibility without design modification.

Selection among active substitutes should prioritize parts with the widest operating temperature range and highest inventory availability for production continuity. SMBJ85CA-TP (Micro Commercial Co) offers the extended upper temperature limit of 175°C, providing additional thermal margin in high-temperature environments.

Frequently Asked Questions (FAQ)

Q: Can SMBJ85CA directly replace SMBJ85C without circuit modification?

A: Yes. Both parts maintain 85V reverse standoff voltage, 600W peak pulse power, and identical DO-214AA (SMB) packaging. The clamping voltage difference (143.85V vs. 137V) is within acceptable tolerance for general-purpose protection circuits. No PCB layout changes are required.

Q: What is the significance of the clamping voltage difference between SMBJ85C and substitute parts?

A: The SMBJ85C specifies 143.85V maximum clamping voltage, while substitutes specify 137V maximum. This 6.85V difference represents the maximum voltage transient that the diode will clamp to during a surge event. For most general-purpose applications, both specifications provide adequate circuit protection. Circuit designers should verify that downstream components tolerate the substitute's 137V clamping level.

Q: Are packaging variants (Tape & Reel, Cut Tape) interchangeable?

A: Yes. Packaging variants (TR, CT) refer only to supply format and do not affect component electrical performance or PCB mounting. SMBJ85CA, SMBJ85CA-13-F, SMBJ85CA-M3/52, SMBJ85CA-M3/5B, and SMBJ85CA-TP are electrically identical; packaging selection depends on assembly process requirements and order quantity.

Q: Why is the SMBJ85C classified as obsolete?

A: Littelfuse Inc. has discontinued the SMBJ85C in favor of active product lines. Multiple manufacturers now produce functionally equivalent 85V TVS diodes in the same package, providing superior supply chain stability and manufacturing support.

Q: Does operating temperature range affect substitution suitability?

A: The SMBJ85C operates from -65°C to 150°C, while most substitutes operate from -55°C to 150°C. The 10°C difference at the lower temperature limit is negligible for most applications. SMBJ85CA-TP extends to 175°C, offering additional thermal headroom for high-temperature environments. Verify application temperature requirements before final part selection.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic component procurement.

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