1SMB75AT3G Equivalent & Substitute Parts

Part Overview

The 1SMB75AT3G is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc. in the DO-214AA (SMB) surface mount package. This unidirectional Zener-type device provides transient voltage protection for general-purpose applications with a 75V reverse standoff voltage and 121V maximum clamping voltage at peak pulse current. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	75	V
Voltage - Breakdown (Min)	83.3	V
Voltage - Clamping (Max) @ Ipp	121	V
Current - Peak Pulse (10/1000µs)	4.9	A
Power - Peak Pulse	600	W
Operating Temperature Range	-65 to 150	°C (TJ)
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the 1SMB75AT3G is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff: 75V (nominal)
Voltage - Breakdown (Min): 83.3V
Voltage - Clamping (Max) @ Ipp: 121V or 134V (acceptable variance)
Current - Peak Pulse (10/1000µs): 4.5A to 5A (acceptable range)
Power - Peak Pulse: 600W
Package / Case: DO-214AA (SMB)
Mounting Type: Surface Mount
Type: Zener, Unidirectional
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level: 1 (Unlimited)

Substitute parts are grouped into two categories: direct equivalents with identical clamping voltage (121V) and functional equivalents with slightly elevated clamping voltage (134V). All substitutes maintain the same reverse standoff voltage, breakdown voltage, power rating, package, and compliance certifications.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Product Status	Voltage - Reverse Standoff (Typ)	Voltage - Breakdown (Min)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Package / Case	RoHS Status
1SMB75AT3G	Littelfuse Inc.	Obsolete	75V	83.3V	121V	4.9A	600W	-65 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A-HR	Littelfuse Inc.	Active	75V	83.3V	121V	5A	600W	-65 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A-HRA	Littelfuse Inc.	Active	75V	83.3V	121V	5A	600W	-65 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A	Meritek	Active	75V	83.3V	121V	4.96A	600W	-55 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A-13-F	Diodes Incorporated	Active	75V	83.3V	121V	4.9A	600W	-55 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A-M3/52	Vishay General Semiconductor - Diodes Division	Active	75V	83.3V	121V	5A	600W	-55 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75A-M3/5B	Vishay General Semiconductor - Diodes Division	Active	75V	83.3V	121V	5A	600W	-55 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75AE3/TR13	Microchip Technology	Active	75V	83.3V	121V	4.9A	600W	-65 to 150°C	DO-214AA, SMB	ROHS3 Compliant
SMBJ75E3/TR13	Microchip Technology	Active	75V	83.3V	134V	4.5A	600W	-65 to 150°C	DO-214AA, SMB	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, matching the original 1SMB75AT3G specifications. Selection among substitutes depends on application-specific requirements:

For direct electrical equivalence with 121V clamping voltage, SMBJ75A-HR, SMBJ75A-HRA, SMBJ75A (Meritek), SMBJ75A-13-F, SMBJ75A-M3/52, SMBJ75A-M3/5B, and SMBJ75AE3/TR13 are functionally identical. The Littelfuse SMBJ75A-HR and SMBJ75A-HRA maintain the original manufacturer lineage and extended temperature range (-65 to 150°C), providing continuity with the obsolete 1SMB75AT3G.

SMBJ75E3/TR13 offers an alternative with elevated clamping voltage (134V) and reduced peak pulse current (4.5A), suitable for applications requiring higher voltage margin at the cost of lower current handling.

Temperature range considerations: Littelfuse and Microchip parts support -65°C minimum operating temperature, while Meritek, Diodes Incorporated, and Vishay parts support -55°C minimum. Applications requiring operation below -55°C must use Littelfuse or Microchip alternatives.

Frequently Asked Questions (FAQ)

Q: Can SMBJ75E3/TR13 be used as a direct replacement for 1SMB75AT3G?

A: SMBJ75E3/TR13 is functionally compatible but not a direct replacement. It maintains the same reverse standoff voltage (75V) and power rating (600W) but has a higher clamping voltage (134V vs. 121V) and lower peak pulse current (4.5A vs. 4.9A). Use this part only if the application circuit can tolerate the higher clamping voltage.

Q: What is the difference between SMBJ75A-HR and SMBJ75A-HRA?

A: Both parts are manufactured by Littelfuse Inc. with identical electrical specifications (75V standoff, 121V clamping, 5A peak pulse current, 600W power rating, -65 to 150°C operating range, and DO-214AA SMB package). The suffix difference (-HR vs. -HRA) indicates packaging or tape configuration variants. Electrical performance is equivalent.

Q: Are all substitute parts available in the same SMB package?

A: Yes. All substitute parts listed use the DO-214AA (SMB) surface mount package, maintaining mechanical compatibility with the original 1SMB75AT3G footprint and assembly process.

Q: Which substitute offers the best temperature range coverage?

A: Littelfuse (SMBJ75A-HR, SMBJ75A-HRA) and Microchip (SMBJ75AE3/TR13, SMBJ75E3/TR13) parts support the full -65 to 150°C operating range, matching the original 1SMB75AT3G. Meritek, Diodes Incorporated, and Vishay alternatives support -55 to 150°C, which is acceptable for most general-purpose applications but may not suit extreme low-temperature environments.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 Compliant certification and MSL 1 (Unlimited) moisture sensitivity rating, matching the compliance profile of the original 1SMB75AT3G.

Q: What is the peak pulse current tolerance across substitutes?

A: The original 1SMB75AT3G specifies 4.9A peak pulse current. Substitute parts range from 4.5A to 5A. This variation is within acceptable tolerance for general-purpose TVS applications. SMBJ75E3/TR13 at 4.5A represents the lower bound; all others fall between 4.9A and 5A.

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