1SMA33CAT3 Equivalent & Substitute Parts

Part Overview

The 1SMA33CAT3 is a bidirectional Transient Voltage Suppressor (TVS) diode manufactured by onsemi, designed for surface mount applications in the DO-214AC (SMA) package. This component provides 33V reverse standoff voltage with a 53.3V maximum clamping voltage and 7.5A peak pulse current capability. The part is classified as obsolete, making identification of active equivalent and substitute components essential for ongoing design support and procurement.

Key Parameters

Parameter	Value	Unit
Manufacturer Part Number	1SMA33CAT3	—
Manufacturer	onsemi	—
Category	Transient Voltage Suppressors (TVS)	—
Package / Case	DO-214AC, SMA	—
Type	Zener	—
Bidirectional Channels	1	—
Voltage - Reverse Standoff (Typ)	33	V
Voltage - Breakdown (Min)	36.7	V
Voltage - Clamping (Max) @ Ipp	53.3	V
Current - Peak Pulse (10/1000µs)	7.5	A
Power - Peak Pulse	400	W
Capacitance @ Frequency	190	pF @ 1MHz
Operating Temperature	-65 to 150	°C (TJ)
Mounting Type	Surface Mount	—
RoHS Status	RoHS non-compliant	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the 1SMA33CAT3 is determined by strict electrical and mechanical parameter matching within the TVS diode category. The critical parameters that define substitutability are:

Voltage - Reverse Standoff (Typ): 33V
Voltage - Breakdown (Min): 36.7V
Package / Case: DO-214AC, SMA
Mounting Type: Surface Mount
Bidirectional Channels: 1
Type: Zener

Substitute parts are grouped into two categories:

Direct Electrical Equivalents maintain identical or functionally equivalent clamping voltage (53.3V), peak pulse current (7.5A), and power dissipation (400W) specifications. These parts are pin-compatible and electrically interchangeable without circuit modification.

Similar Electrical Alternatives share the same reverse standoff voltage (33V), breakdown voltage (36.7V), and package format but may differ in clamping voltage, peak pulse current, or power rating. These parts require circuit-level evaluation to confirm suitability for the intended application.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Breakdown Min (V)	Voltage - Clamping Max @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Package	Product Status	RoHS Status
1SMA33CAT3	onsemi	33	36.7	53.3	7.5	400	DO-214AC, SMA	Obsolete	RoHS non-compliant
SMAJ33CA	Good-Ark Semiconductor	33	36.7	53.3	7.5	400	DO-214AC, SMA	Active	ROHS3 Compliant
SMAJ33CA-TR	STMicroelectronics	33	36.7	69.7	33 (8/20µs)	400	DO-214AC, SMA	Active	ROHS3 Compliant
SM4T39CAY	STMicroelectronics	33	36.7	69.7	33 (8/20µs)	400	DO-214AC, SMA	Active	ROHS3 Compliant
SMA6J33CA-TR	STMicroelectronics	33	36.7	60.8	57 (8/20µs)	600	DO-214AC, SMA	Active	ROHS3 Compliant
SMAJ33CA-13-F	Diodes Incorporated	33	36.7	53.3	7.5	400	DO-214AC, SMA	Active	ROHS3 Compliant
SMAJ33CA-TP	Micro Commercial Co	33	36.7	53.3	7.5	400	DO-214AC, SMA	Active	ROHS3 Compliant
SMAJ33CAE3/TR13	Microchip Technology	33	36.7	53.3	9.4	500	DO-214AC, SMA	Active	ROHS3 Compliant
TV04A330JB-G	Comchip Technology	33	36.7	53.3	7.5	400	DO-214AC, SMA	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Electrical Equivalents (Recommended for Pin-Compatible Replacement)

SMAJ33CA (Good-Ark Semiconductor), SMAJ33CA-13-F (Diodes Incorporated), SMAJ33CA-TP (Micro Commercial Co), and TV04A330JB-G (Comchip Technology) provide identical electrical specifications to the 1SMA33CAT3. All substitute parts are active products with ROHS3 compliance, addressing the obsolescence and RoHS non-compliance status of the original component. These parts maintain 33V reverse standoff voltage, 36.7V minimum breakdown voltage, 53.3V maximum clamping voltage, 7.5A peak pulse current, and 400W power dissipation. Selection among these equivalents should be based on availability, lead time, and procurement cost.

Enhanced Performance Alternatives (Conditional Substitution)

SMAJ33CAE3/TR13 (Microchip Technology) offers increased peak pulse current (9.4A) and power dissipation (500W) while maintaining the same voltage specifications and package format. This part provides additional margin for transient protection and is suitable for applications requiring higher energy absorption capacity.

SMA6J33CA-TR (STMicroelectronics) provides significantly higher peak pulse current (57A at 8/20µs) and power dissipation (600W), with a clamping voltage of 60.8V. This part is appropriate for high-energy transient environments but requires verification that the increased clamping voltage remains within circuit tolerance limits.

SMAJ33CA-TR and SM4T39CAY (both STMicroelectronics) offer 33A peak pulse current (8/20µs) and 69.7V clamping voltage. These parts are suitable for applications with higher transient energy requirements, provided the elevated clamping voltage is compatible with downstream circuit components.

Compliance Considerations

All active substitute parts listed are ROHS3 compliant, providing regulatory advantage over the obsolete, RoHS non-compliant 1SMA33CAT3. Procurement of active, compliant alternatives ensures long-term supply chain viability and regulatory alignment.

Frequently Asked Questions (FAQ)

Q: Can SMAJ33CA-TR be used as a direct replacement for 1SMA33CAT3?

A: SMAJ33CA-TR shares the same reverse standoff voltage (33V), breakdown voltage (36.7V), and package format (DO-214AC, SMA). However, it differs in clamping voltage (69.7V vs. 53.3V) and peak pulse current (33A vs. 7.5A). Substitution requires circuit-level evaluation to confirm that the higher clamping voltage does not exceed component voltage ratings downstream of the TVS diode.

Q: What is the difference between SMAJ33CA and SMAJ33CA-TP?

A: Both parts are electrically identical with 33V reverse standoff voltage, 36.7V breakdown voltage, 53.3V clamping voltage, 7.5A peak pulse current, and 400W power dissipation. The primary difference is packaging format: SMAJ33CA is available in Cut Tape (CT) and Digi-Reel formats, while SMAJ33CA-TP is supplied in Tape & Reel (TR) format. Selection depends on procurement and assembly requirements.

Q: Is SMA6J33CA-TR suitable for the same application as 1SMA33CAT3?

A: SMA6J33CA-TR maintains the same reverse standoff voltage (33V) and breakdown voltage (36.7V) but provides enhanced performance with 57A peak pulse current (8/20µs), 600W power dissipation, and 60.8V clamping voltage. This part is suitable for applications requiring higher transient energy absorption. Verify that the increased clamping voltage is compatible with circuit requirements.

Q: Why are all substitute parts ROHS3 compliant while the original 1SMA33CAT3 is not?

A: The 1SMA33CAT3 is an obsolete component manufactured before widespread RoHS compliance requirements. All active substitute parts listed are manufactured to current RoHS3 standards, ensuring regulatory compliance and long-term supply chain availability.

Q: Can SMAJ33CAE3/TR13 be used in place of 1SMA33CAT3?

A: Yes. SMAJ33CAE3/TR13 maintains identical voltage specifications (33V reverse standoff, 36.7V breakdown, 53.3V clamping) and package format (DO-214AC, SMA). It provides enhanced performance with 9.4A peak pulse current and 500W power dissipation compared to the original 7.5A and 400W. This part is a direct upgrade suitable for the same application.

Q: What packaging formats are available for substitute parts?

A: Substitute parts are available in Cut Tape (CT), Digi-Reel, and Tape & Reel (TR) formats. Selection depends on assembly process requirements and procurement volume. All parts maintain the same DO-214AC (SMA) component package format, ensuring mechanical compatibility.

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