1SMB85AT3G Equivalent & Substitute Parts

Part Overview

The 1SMB85AT3G is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc. in the DO-214AA (SMB) surface mount package. This component is designed for general-purpose transient voltage suppression applications with an 85V reverse standoff voltage and 137V maximum clamping voltage. The part is currently listed as obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	1SMB85AT3G
Manufacturer	Littelfuse Inc.
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Unidirectional Channels	1
Voltage - Reverse Standoff (Typ)	85V
Voltage - Breakdown (Min)	94.4V
Voltage - Clamping (Max) @ Ipp	137V
Current - Peak Pulse (10/1000µs)	4.4A
Power - Peak Pulse	600W
Package / Case	DO-214AA, SMB
Mounting Type	Surface Mount
Operating Temperature	-65°C ~ 150°C (TJ)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the 1SMB85AT3G is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 85V
Voltage - Breakdown (Min): 94.4V
Voltage - Clamping (Max) @ Ipp: 137V
Current - Peak Pulse (10/1000µs): 4.4A (or within 0.02A tolerance)
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB
Mounting Type: Surface Mount
Type: Zener
Unidirectional Channels: 1
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

All substitute parts listed maintain these core electrical specifications and physical package requirements, ensuring direct functional replacement in existing circuit designs.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Product Status	Inventory
1SMB85AT3G	Littelfuse Inc.	85V	94.4V	137V	4.4A	600W	-65°C ~ 150°C (TJ)	Obsolete	30400 Pcs
SMBJ85A	Meritek	85V	94.4V	137V	4.38A	600W	-55°C ~ 150°C	Active	2060 Pcs
SMBJ85A-HR	Littelfuse Inc.	85V	94.4V	137V	4.4A	600W	-65°C ~ 150°C (TJ)	Active	3435 Pcs
SMBJ85A-HRA	Littelfuse Inc.	85V	94.4V	137V	4.4A	600W	-65°C ~ 150°C (TJ)	Active	658 Pcs
SMBJ85A-13-F	Diodes Incorporated	85V	94.4V	137V	4.4A	600W	-55°C ~ 150°C (TJ)	Active	4344 Pcs
SMBJ85A-M3/52	Vishay General Semiconductor - Diodes Division	85V	94.4V	137V	4.4A	600W	-55°C ~ 150°C (TJ)	Active	940 Pcs
SMBJ85A-M3/5B	Vishay General Semiconductor - Diodes Division	85V	94.4V	137V	4.4A	600W	-55°C ~ 150°C (TJ)	Active	778 Pcs
TV06B850J-G	Comchip Technology	85V	94.4V	137V	4.38A	600W	Not specified	Active	745 Pcs

Engineering Selection Recommendations

All listed substitute parts are ROHS3 compliant and maintain MSL 1 (Unlimited) moisture sensitivity rating, matching the original 1SMB85AT3G specifications.

For applications requiring the full -65°C to 150°C operating temperature range of the original part, select from: SMBJ85A-HR, SMBJ85A-HRA (both Littelfuse Inc., active status). These parts are direct successors from the original manufacturer and provide identical electrical performance with extended product lifecycle support.

For applications operating within -55°C to 150°C, active alternatives include SMBJ85A-13-F (Diodes Incorporated), SMBJ85A-M3/52, and SMBJ85A-M3/5B (Vishay General Semiconductor - Diodes Division). These parts deliver equivalent electrical specifications with higher current inventory availability.

SMBJ85A (Meritek) and TV06B850J-G (Comchip Technology) provide functional equivalence with peak pulse current of 4.38A, within acceptable tolerance of the original 4.4A specification.

Frequently Asked Questions (FAQ)

Q: Can SMBJ85A-HR directly replace 1SMB85AT3G in existing designs?

A: Yes. SMBJ85A-HR maintains identical electrical parameters (85V standoff, 137V clamping, 4.4A peak pulse) and operating temperature range (-65°C to 150°C). Both use DO-214AA (SMB) surface mount packaging. This is the recommended direct replacement from Littelfuse Inc.

Q: What is the difference between SMBJ85A-HR and SMBJ85A-HRA?

A: Both parts are manufactured by Littelfuse Inc. with identical electrical specifications and operating temperature range. SMBJ85A-HRA is available in lower inventory (658 Pcs vs. 3435 Pcs for SMBJ85A-HR). Selection between these variants should be based on procurement availability and lead time requirements.

Q: Are Vishay TransZorb® parts (SMBJ85A-M3/52, SMBJ85A-M3/5B) compatible?

A: Yes. Both Vishay parts maintain the required 85V standoff, 137V clamping, and 4.4A peak pulse specifications in DO-214AA (SMB) packaging. Operating temperature range is -55°C to 150°C, which is suitable for applications not requiring the full -65°C lower limit.

Q: What is the significance of the 4.38A vs. 4.4A peak pulse current difference?

A: The 0.02A difference between SMBJ85A (Meritek) and TV06B850J-G (Comchip Technology) versus the original 4.4A specification falls within normal manufacturing tolerance for TVS diodes. Both parts are functionally equivalent for general-purpose transient voltage suppression applications.

Q: Can I use SMBJ85A (Meritek) if my application operates below -55°C?

A: No. SMBJ85A is rated for -55°C to 150°C operating temperature. If your application requires operation at -65°C, select SMBJ85A-HR or SMBJ85A-HRA from Littelfuse Inc., which are rated to -65°C.

Q: Are all substitute parts available in Tape & Reel (TR) packaging?

A: SMBJ85A-HR, SMBJ85A-HRA, SMBJ85A-13-F, SMBJ85A-M3/52, and SMBJ85A-M3/5B are supplied in Tape & Reel packaging. SMBJ85A (Meritek) and TV06B850J-G (Comchip Technology) packaging specifications are not detailed but are compatible with standard SMB assembly processes.

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