1SMB45AT3G Equivalent & Substitute Parts

Part Overview

The 1SMB45AT3G 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 a 45V reverse standoff voltage with 72.7V maximum clamping voltage and 8.3A peak pulse current capability in a DO-214AA (SMB) package. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain identical electrical and mechanical specifications for continued system support and new designs.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	45	V
Voltage - Breakdown (Min)	50	V
Voltage - Clamping (Max) @ Ipp	72.7	V
Current - Peak Pulse (10/1000µs)	8.3	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	—
Operating Temperature Range	-65 to 150	°C (TJ)
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the 1SMB45AT3G is determined by strict equivalence across the following electrical and mechanical parameters:

Voltage - Reverse Standoff: 45V (typical)
Voltage - Breakdown: 50V (minimum)
Voltage - Clamping: 72.7V (maximum at Ipp)
Current - Peak Pulse: 8.3A (10/1000µs)
Power - Peak Pulse: 600W
Package: DO-214AA / SMB (surface mount)
Unidirectional configuration (single channel)
General-purpose applications
RoHS3 compliance and MSL 1 rating

All identified substitute parts maintain these core electrical specifications and package requirements. Variations in operating temperature range, capacitance characteristics, or manufacturer series designation do not affect functional substitutability when the above parameters are matched.

Parameter Comparison

Part Number	Manufacturer	VWM (V)	VBR (V)	VC (V)	Ipp (A)	PPP (W)	Package	Status	Temp Range (°C)
1SMB45AT3G	Littelfuse Inc.	45	50	72.7	8.3	600	DO-214AA, SMB	Obsolete	-65 to 150
SMBJ45A	MDD	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-50 to 150
SACB45	Littelfuse Inc.	45	50	77	6.8	500	DO-214AA, SMB	Active	-55 to 150
SMBJ45A-HR	Littelfuse Inc.	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-65 to 150
SMBJ45A-HRA	Littelfuse	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-65 to 150
SMBJ45A-13-F	Diodes Incorporated	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-55 to 150
SMBJ45A-M3/52	Vishay General Semiconductor - Diodes Division	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-55 to 150
SMBJ45A-M3/5B	Vishay General Semiconductor - Diodes Division	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-55 to 150
SMBJ45AE3/TR13	Microchip Technology	45	50	72.7	8.3	600	DO-214AA, SMB	Active	-65 to 150

Engineering Selection Recommendations

Direct electrical equivalents with identical clamping voltage (72.7V) and peak pulse current (8.3A) are available from multiple manufacturers in active production status:

Primary Equivalents (Full Parameter Match):

SMBJ45A-HR (Littelfuse Inc.) — Active status, original manufacturer alternative, -65 to 150°C operating range
SMBJ45A-HRA (Littelfuse) — Active status, original manufacturer alternative, -65 to 150°C operating range
SMBJ45AE3/TR13 (Microchip Technology) — Active status, -65 to 150°C operating range
SMBJ45A-13-F (Diodes Incorporated) — Active status, -55 to 150°C operating range
SMBJ45A-M3/52 (Vishay General Semiconductor - Diodes Division) — Active status, -55 to 150°C operating range
SMBJ45A-M3/5B (Vishay General Semiconductor - Diodes Division) — Active status, -55 to 150°C operating range
SMBJ45A (MDD) — Active status, -50 to 150°C operating range

All listed equivalents maintain RoHS3 compliance and MSL 1 rating. Selection among these alternatives depends on supply chain availability, packaging format (tape & reel vs. bulk), and specific operating temperature requirements for the application.

Secondary Alternative (Modified Electrical Characteristics):

SACB45 (Littelfuse Inc.) — Active status, original manufacturer product. Note: Clamping voltage is 77V (vs. 72.7V) and peak pulse current is 6.8A (vs. 8.3A). This part is suitable only for applications where the higher clamping voltage and lower current rating are acceptable.

Frequently Asked Questions (FAQ)

Q: Can SACB45 be used as a direct replacement for 1SMB45AT3G?

A: SACB45 is not a direct electrical equivalent. While it maintains the same 45V reverse standoff voltage and DO-214AA package, the clamping voltage is 77V (compared to 72.7V) and peak pulse current is 6.8A (compared to 8.3A). Use SACB45 only if your circuit design tolerates these parameter differences.

Q: What is the difference between SMBJ45A-HR and SMBJ45A-HRA?

A: Both parts are manufactured by Littelfuse and share identical electrical specifications (45V standoff, 72.7V clamping, 8.3A peak pulse) and operating temperature range (-65 to 150°C). The designation difference reflects internal product line organization. Either part is functionally equivalent for the 1SMB45AT3G application.

Q: Does operating temperature range affect substitutability?

A: Operating temperature range does not affect electrical substitutability if the substitute part's range encompasses your application requirements. The 1SMB45AT3G operates from -65 to 150°C. Substitutes with narrower ranges (such as -50 to 150°C or -55 to 150°C) are suitable for applications operating within those limits.

Q: Are all substitute parts available in tape & reel packaging?

A: Packaging format varies by manufacturer and supplier. SMBJ45A (MDD) is available in standard packaging. Littelfuse SMBJ45A-HR and SMBJ45A-HRA, Vishay SMBJ45A-M3/52 and SMBJ45A-M3/5B, Diodes SMBJ45A-13-F, and Microchip SMBJ45AE3/TR13 are available in tape & reel format. Confirm packaging availability with your supplier.

Q: Is the 1SMB45AT3G still manufactured?

A: No. The 1SMB45AT3G is classified as obsolete. All listed substitute parts are in active production status and are recommended for new designs and legacy system support.

Q: Do all substitute parts meet RoHS3 and MSL 1 requirements?

A: Yes. All identified substitute parts are RoHS3 compliant with MSL 1 (unlimited moisture sensitivity level) rating, matching the compliance profile of the original 1SMB45AT3G.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message