Equivalent & Substitute Parts for 1SMB75AT3

Part Overview

The 1SMB75AT3 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 75V reverse standoff voltage with a 121V maximum clamping voltage and 4.9A peak pulse current capability in the DO-214AA (SMB) package. The part is currently listed as obsolete, making identification of active equivalent and substitute components essential for ongoing design support and procurement.

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
Package / Case	DO-214AA, SMB	—
Operating Temperature	-65°C ~ 150°C	TJ
Type	Zener	—
Unidirectional Channels	1	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution for the 1SMB75AT3 is determined by strict equivalence across the following critical parameters:

Voltage - Reverse Standoff (Typ): 75V
Voltage - Clamping (Max) @ Ipp: 121V
Current - Peak Pulse (10/1000µs): 4.9A (±tolerance acceptable)
Package / Case: DO-214AA (SMB)
Type: Zener, Unidirectional
Power - Peak Pulse: 600W

Substitute parts are classified into two categories:

Direct Equivalents: Parts with identical electrical specifications (75V standoff, 121V clamp, 4.9A peak pulse) and active product status.

Similar Alternatives: Parts with comparable but not identical specifications that may serve the same circuit function with engineering evaluation. These include parts with voltage variations (70V standoff) or clamping voltage variations (134V clamp) that remain within the same product family and package.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Package	Product Status	RoHS Status
1SMB75AT3	onsemi	75	121	4.9	600	DO-214AA, SMB	Obsolete	RoHS non-compliant
SMBJ75A	Meritek	75	121	4.96	600	DO-214AA (SMB)	Active	ROHS3 Compliant
SMBJ75A-13-F	Diodes Incorporated	75	121	4.9	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ75A-HR	Littelfuse Inc.	75	121	5	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ75A-HRA	Littelfuse Inc.	75	121	5	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ75AE3/TR13	Microchip Technology	75	121	4.9	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ75E3/TR13	Microchip Technology	75	134	4.5	600	DO-214AA, SMB	Active	ROHS3 Compliant
SMBJ70CA-TP	Micro Commercial Co	70	113	5.3	600	DO-214AA, SMB	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalents (Recommended for 1:1 Replacement):

SMBJ75A-13-F (Diodes Incorporated) and SMBJ75AE3/TR13 (Microchip Technology) provide exact electrical equivalence to the 1SMB75AT3 with active product status and ROHS3 compliance. Both maintain 75V reverse standoff, 121V clamping voltage, and 4.9A peak pulse current in the DO-214AA (SMB) package. These parts are suitable for direct substitution in new designs and legacy system support.

SMBJ75A (Meritek) offers electrical equivalence with 4.96A peak pulse current (within tolerance of the original 4.9A specification) and active product status with ROHS3 compliance.

High-Current Alternatives (Equivalent Voltage, Enhanced Current Rating):

SMBJ75A-HR and SMBJ75A-HRA (Littelfuse Inc.) maintain identical voltage specifications (75V standoff, 121V clamp) with a 5A peak pulse current rating, providing a 2% increase over the original 4.9A specification. Both are ROHS3 compliant and active. These parts are suitable where additional current margin is beneficial.

Voltage-Variant Alternative (Lower Voltage Rating):

SMBJ70CA-TP (Micro Commercial Co) operates at 70V reverse standoff with 113V clamping voltage and 5.3A peak pulse current. This part is suitable only for applications where the lower voltage rating is acceptable and provides enhanced current handling capability.

Voltage-Variant Alternative (Higher Clamping Voltage):

SMBJ75E3/TR13 (Microchip Technology) maintains 75V reverse standoff but features 134V maximum clamping voltage with 4.5A peak pulse current. This part is suitable for applications requiring higher clamping voltage tolerance.

All recommended substitutes are ROHS3 compliant and carry active product status, ensuring long-term availability and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can SMBJ75A-13-F directly replace 1SMB75AT3 in existing designs?

A: Yes. SMBJ75A-13-F provides identical electrical specifications (75V standoff, 121V clamp, 4.9A peak pulse) in the same DO-214AA (SMB) package. The part is pin-compatible and electrically equivalent.

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

A: Both parts are electrically identical with 75V standoff, 121V clamping voltage, and 5A peak pulse current in the DO-214AA (SMB) package. The "-HRA" designation indicates a variant series designation from Littelfuse Inc. Both are suitable substitutes.

Q: Is SMBJ70CA-TP a suitable replacement for 1SMB75AT3?

A: SMBJ70CA-TP operates at a lower voltage rating (70V standoff, 113V clamp) compared to the original 1SMB75AT3 (75V standoff, 121V clamp). This part is suitable only if the circuit design permits operation at the lower voltage threshold.

Q: Why is SMBJ75E3/TR13 listed as a similar alternative rather than a direct equivalent?

A: SMBJ75E3/TR13 features a higher maximum clamping voltage (134V versus 121V) and lower peak pulse current (4.5A versus 4.9A). While the 75V reverse standoff voltage matches, the clamping voltage variation requires circuit evaluation before substitution.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original 1SMB75AT3 is RoHS non-compliant due to its obsolete status. Substitution with ROHS3-compliant alternatives ensures regulatory compliance in new designs and updated systems.

Q: What packaging options are available for these substitutes?

A: All substitute parts are available in DO-214AA (SMB) surface-mount package, matching the original 1SMB75AT3 footprint. Packaging variants (Cut Tape, Tape & Reel) are available from individual suppliers but do not affect electrical compatibility.

Q: Can I use SMBJ75A (Meritek) as a drop-in replacement?

A: Yes. SMBJ75A provides electrical equivalence with 4.96A peak pulse current (within tolerance of the 4.9A original specification), 75V standoff, and 121V clamping voltage. The part is ROHS3 compliant and active.

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