1SMA30AT3 Equivalent & Substitute Parts

Part Overview

The 1SMA30AT3 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by onsemi, designed for general-purpose transient protection applications. This component features a 30V reverse standoff voltage with a 48.4V maximum clamping voltage at peak pulse current of 8.3A, housed in a surface-mount SMA (DO-214AC) package. The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	1SMA30AT3
Manufacturer	onsemi
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Unidirectional Channels	1
Voltage - Reverse Standoff (Typ)	30V
Voltage - Breakdown (Min)	33.3V
Voltage - Clamping (Max) @ Ipp	48.4V
Current - Peak Pulse (10/1000µs)	8.3A
Power - Peak Pulse	400W
Package / Case	DO-214AC, SMA
Mounting Type	Surface Mount
Operating Temperature	-65°C ~ 150°C (TJ)
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitute parts for the 1SMA30AT3 are classified based on strict electrical and mechanical parameter alignment:

Direct Equivalents maintain identical electrical specifications: 30V reverse standoff voltage, 33.3V minimum breakdown voltage, 48.4V maximum clamping voltage, 8.3A peak pulse current, and 400W peak pulse power. These parts are pin-compatible and functionally interchangeable in the same circuit application without design modification.

Similar Substitutes share the core voltage protection parameters (30V standoff, 33.3V breakdown, 48.4V clamping) and identical package format (DO-214AC/SMA) but may differ in peak pulse current ratings, clamping voltage specifications, or operating temperature ranges. These parts require verification of application-specific current handling requirements before selection.

Key Parameters for Substitution Eligibility:

Voltage - Reverse Standoff: 30V
Voltage - Breakdown (Min): 33.3V
Voltage - Clamping (Max) @ Ipp: 48.4V (±tolerance acceptable)
Package / Case: DO-214AC, SMA
Mounting Type: Surface Mount
Unidirectional Channels: 1

Parameter Comparison

Part Number	Manufacturer	Standoff Voltage	Breakdown Voltage (Min)	Clamping Voltage (Max)	Peak Pulse Current	Peak Pulse Power	Package	Operating Temp	Product Status	RoHS Status
1SMA30AT3	onsemi	30V	33.3V	48.4V	8.3A	400W	DO-214AC, SMA	-65°C ~ 150°C	Obsolete	RoHS non-compliant
SMAJ30A	MDD	30V	33.3V	48.4V	8.3A	400W	DO-214AC, SMA	-50°C ~ 150°C	Active	ROHS3 Compliant
PTVS30VS1UR,115	Nexperia USA Inc.	30V	33.3V	48.4V	8.3A	400W	SOD-123W	-55°C ~ 150°C	Active	ROHS3 Compliant
SM4T35AY	STMicroelectronics	30V	33.3V	64.3V	36A (8/20µs)	400W	DO-214AC, SMA	-55°C ~ 150°C	Active	ROHS3 Compliant
SMAJ30A-13-F	Diodes Incorporated	30V	33.3V	48.4V	8.3A	400W	DO-214AC, SMA	-55°C ~ 150°C	Active	ROHS3 Compliant
SMAJ30A-TP	Micro Commercial Co	30V	33.3V	48.4V	8.3A	400W	DO-214AC, SMA	-55°C ~ 175°C	Active	ROHS3 Compliant
SMAJ30A-TR	STMicroelectronics	30V	33.3V	64.3V	36A (8/20µs)	400W	DO-214AC, SMA	-55°C ~ 150°C	Active	ROHS3 Compliant
SMAJ30AE3/TR13	Microchip Technology	30V	33.3V	48.4V	10.3A	500W	DO-214AC, SMA	-65°C ~ 150°C	Active	ROHS3 Compliant
SMAJ30E3/TR13	Microchip Technology	30V	33.3V	54.6V	9.3A	500W	DO-214AC, SMA	-65°C ~ 150°C	Active	ROHS3 Compliant
TV04A300J-G	Comchip Technology	30V	33.3V	48.4V	8.26A	400W	DO-214AC, SMA	-55°C ~ 150°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Identical Electrical Performance): SMAJ30A (MDD), SMAJ30A-13-F (Diodes Incorporated), and TV04A300J-G (Comchip Technology) provide direct electrical equivalence to the 1SMA30AT3 with matching 30V standoff, 33.3V breakdown, 48.4V clamping, and 8.3A peak pulse current specifications. All three are active products with ROHS3 compliance, addressing the obsolescence and RoHS non-compliance status of the original part.

Enhanced Performance Alternatives (Higher Current/Power Rating): SMAJ30AE3/TR13 (Microchip Technology) and SMAJ30E3/TR13 (Microchip Technology) maintain voltage specifications while offering increased peak pulse current (10.3A and 9.3A respectively) and higher peak pulse power (500W). These parts are suitable for applications requiring additional transient energy absorption margin. SMAJ30AE3/TR13 matches the original operating temperature range (-65°C ~ 150°C).

Package Variant (Different Form Factor): PTVS30VS1UR,115 (Nexperia USA Inc.) provides electrical equivalence but uses SOD-123W packaging instead of SMA. This part is suitable only if PCB layout accommodates the alternative package geometry.

Higher Clamping Voltage Variants (Not Recommended for Direct Substitution): SM4T35AY (STMicroelectronics) and SMAJ30A-TR (STMicroelectronics) feature 64.3V clamping voltage with significantly higher peak pulse current (36A). These parts do not maintain electrical equivalence and are suitable only for applications with different voltage protection requirements.

Compliance Consideration: All recommended substitute parts carry ROHS3 compliance certification, resolving the RoHS non-compliance status of the obsolete 1SMA30AT3.

Frequently Asked Questions (FAQ)

Q: Can SMAJ30A directly replace 1SMA30AT3 without circuit modification? A: Yes. SMAJ30A maintains identical electrical specifications (30V standoff, 33.3V breakdown, 48.4V clamping, 8.3A peak pulse current) and identical SMA package format. No circuit design changes are required.

Q: What is the difference between SMAJ30A-13-F and SMAJ30A-TP? A: Both parts share identical electrical specifications and SMA packaging. The primary difference is operating temperature range: SMAJ30A-TP extends to 175°C (versus 150°C for SMAJ30A-13-F), providing enhanced thermal margin for high-temperature applications.

Q: Why do SM4T35AY and SMAJ30A-TR show higher clamping voltage (64.3V)? A: These parts are from different product lines within their respective manufacturers' TVS portfolios. The 64.3V clamping voltage represents a different protection level and is not electrically equivalent to the 1SMA30AT3. Selection of these parts requires application-specific voltage protection requirements verification.

Q: Is PTVS30VS1UR,115 a suitable replacement? A: PTVS30VS1UR,115 provides electrical equivalence but uses SOD-123W packaging instead of SMA (DO-214AC). This part is suitable only if the PCB layout and footprint accommodate the SOD-123W form factor. Verify mechanical compatibility before selection.

Q: Which substitute part offers the best thermal performance? A: SMAJ30A-TP (Micro Commercial Co) extends operating temperature to 175°C, providing the highest thermal rating among direct electrical equivalents. SMAJ30AE3/TR13 and SMAJ30E3/TR13 (Microchip Technology) match the original -65°C lower temperature limit.

Q: Are all substitute parts RoHS compliant? A: Yes. All listed substitute parts carry ROHS3 compliance certification, addressing the RoHS non-compliance status of the obsolete 1SMA30AT3.

Q: What is the inventory status of substitute parts? A: SMAJ30A (MDD) offers the highest inventory availability at 28,300 pieces. SMAJ30A-13-F (Diodes Incorporated) provides 17,605 pieces. Availability varies by manufacturer and distributor; verify current stock before procurement.

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