SMAJ33AE3/TR13 Equivalent & Substitute Parts

Part Overview

The SMAJ33AE3/TR13 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Microchip Technology, designed for general-purpose overvoltage protection in surface-mount applications. This component operates with a 33V reverse standoff voltage and provides clamping at 53.3V maximum, with a peak pulse current rating of 9.4A. The device is classified as Active product status and is RoHS3 compliant with unlimited moisture sensitivity level (MSL 1).

Equivalent and substitute parts are identified based on matching electrical characteristics within the 33V voltage class, compatible DO-214AC (SMA) packaging, and equivalent or superior performance ratings. Substitutes are selected from manufacturers offering TVS diodes with identical or enhanced specifications for direct circuit replacement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	33	V
Voltage - Breakdown (Min)	36.7	V
Voltage - Clamping (Max) @ Ipp	53.3	V
Current - Peak Pulse (10/1000µs)	9.4	A
Power - Peak Pulse	500	W
Operating Temperature Range	-65 to 150	°C (TJ)
Package / Case	DO-214AC, SMA	—
Mounting Type	Surface Mount	—
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
MSL Rating	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the SMAJ33AE3/TR13 are grouped based on the following substitution criteria:

Primary Matching Parameters:

Voltage - Reverse Standoff (Typ): 33V
Voltage - Breakdown (Min): 36.7V
Package / Case: DO-214AC, SMA
Mounting Type: Surface Mount
Type: Zener, Unidirectional (1 channel)
RoHS3 Compliance

Substitution Logic:

Parts are classified into two categories based on electrical performance:

Direct Equivalents — Parts with identical clamping voltage (53.3V) and similar peak pulse current (7.5A to 9.4A). These provide equivalent protection characteristics and are interchangeable in applications where the original specification is met.
Enhanced Performance Substitutes — Parts with higher clamping voltages (60.8V to 69.7V) and/or higher peak pulse current ratings (33A to 57A). These provide superior transient suppression capability and are suitable for applications requiring increased margin or higher energy dissipation.

All substitute parts maintain the 33V standoff voltage class, DO-214AC package compatibility, and surface-mount configuration required for direct PCB replacement.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (Max) @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temperature (°C)	Package
SMAJ33AE3/TR13	Microchip Technology	33	53.3	9.4	500	-65 to 150	DO-214AC, SMA
SMAJ33A	MDD	33	53.3	7.5	400	-50 to 150	DO-214AC, SMA
SMAJ33A-13-F	Diodes Incorporated	33	53.3	7.5	400	-55 to 150	DO-214AC, SMA
SMAJ33A-TP	Micro Commercial Co	33	53.3	7.5	400	-55 to 175	DO-214AC, SMA
SMAJ33A-TR	STMicroelectronics	33	69.7	33	400	-55 to 150	DO-214AC, SMA
SMA6J33A-TR	STMicroelectronics	33	60.8	57	600	-55 to 175	DO-214AC, SMA
SZ1SMA33AT3G	Littelfuse Inc.	33	53.3	7.5	400	-65 to 150	DO-214AC, SMA
TV04A330J-G	Comchip Technology	33	53.3	7.5	400	-55 to 150	DO-214AC, SMA
SM4T39AY	STMicroelectronics	33	69.7	33	400	-55 to 150	DO-214AC, SMA

Engineering Selection Recommendations

Direct Equivalent Selection:

The following parts provide equivalent electrical performance to the SMAJ33AE3/TR13 with identical 53.3V clamping voltage and comparable current ratings:

SMAJ33A (MDD): Direct equivalent with 7.5A peak pulse current. Suitable for applications with identical protection requirements. Operating temperature range -50 to 150°C.
SMAJ33A-13-F (Diodes Incorporated): Direct equivalent with 7.5A peak pulse current and RoHS3 compliance. Operating temperature range -55 to 150°C. Active product status.
SMAJ33A-TP (Micro Commercial Co): Direct equivalent with 7.5A peak pulse current and extended upper operating temperature to 175°C. RoHS3 compliant, Active product status.
SZ1SMA33AT3G (Littelfuse Inc.): Direct equivalent with 7.5A peak pulse current. Automotive-grade component with AEC-Q101 qualification. Operating temperature range -65 to 150°C matches original part. RoHS3 compliant, Active product status.
TV04A330J-G (Comchip Technology): Direct equivalent with 7.5A peak pulse current. RoHS3 compliant, Active product status. Operating temperature range -55 to 150°C.

Enhanced Performance Selection:

The following parts provide superior transient suppression capability with higher clamping voltages and peak pulse current ratings:

SMAJ33A-TR (STMicroelectronics): Enhanced performance with 69.7V clamping voltage and 33A peak pulse current (8/20µs). Suitable for applications requiring increased protection margin. RoHS3 compliant, Active product status.
SMA6J33A-TR (STMicroelectronics): Enhanced performance with 60.8V clamping voltage, 57A peak pulse current (8/20µs), and 600W peak pulse power. Extended operating temperature to 175°C. RoHS3 compliant, Active product status.
SM4T39AY (STMicroelectronics): Enhanced performance with 69.7V clamping voltage and 33A peak pulse current (8/20µs). Automotive-grade with AEC-Q101 qualification. RoHS3 compliant, Active product status.

All recommended substitutes maintain RoHS3 compliance, MSL 1 rating, and Active product status. Selection between direct equivalents and enhanced performance parts depends on application-specific transient energy requirements and thermal constraints.

Frequently Asked Questions (FAQ)

Q: Can SMAJ33A (MDD) be used as a direct replacement for SMAJ33AE3/TR13?

A: Yes. Both parts share identical 33V standoff voltage, 53.3V clamping voltage, 7.5A peak pulse current, and DO-214AC package. The primary difference is the operating temperature range: SMAJ33A operates -50 to 150°C versus -65 to 150°C for the original part. Selection depends on whether the lower temperature limit of -50°C is acceptable for your application.

Q: What is the difference between direct equivalents and enhanced performance substitutes?

A: Direct equivalents (SMAJ33A, SMAJ33A-13-F, SMAJ33A-TP, SZ1SMA33AT3G, TV04A330J-G) provide identical 53.3V clamping voltage and 7.5A current ratings. Enhanced performance substitutes (SMAJ33A-TR, SMA6J33A-TR, SM4T39AY) offer higher clamping voltages (60.8V to 69.7V) and significantly higher peak pulse currents (33A to 57A), providing greater transient suppression capability and energy dissipation.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are RoHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity rating, matching the original SMAJ33AE3/TR13 specification.

Q: Can I use SMA6J33A-TR in place of SMAJ33AE3/TR13?

A: Yes, with consideration for enhanced performance. SMA6J33A-TR provides superior transient suppression with 60.8V clamping voltage and 57A peak pulse current versus 53.3V and 9.4A for the original part. The higher ratings provide additional protection margin. Operating temperature extends to 175°C. This substitution is suitable for applications where enhanced protection is beneficial or required.

Q: What is the significance of the 8/20µs pulse specification on some parts?

A: The 8/20µs notation indicates the pulse waveform used for measuring peak pulse current. Parts specified with 8/20µs (SMAJ33A-TR, SMA6J33A-TR, SM4T39AY) use a different measurement standard than the 10/1000µs specification on the original SMAJ33AE3/TR13. Both standards are valid; the 8/20µs waveform is commonly used for power line protection applications, while 10/1000µs is used for general-purpose transient suppression.

Q: Is SZ1SMA33AT3G suitable for automotive applications?

A: Yes. SZ1SMA33AT3G carries automotive-grade qualification with AEC-Q101 certification. It provides direct electrical equivalence to SMAJ33AE3/TR13 with identical 53.3V clamping voltage and 7.5A peak pulse current, plus the added benefit of automotive qualification if required by your application.

Q: What packaging options are available for these substitutes?

A: All substitute parts use DO-214AC (SMA) surface-mount package, identical to the original SMAJ33AE3/TR13. Packaging variants (Tape & Reel, Cut Tape, Digi-Reel) differ only in supply format and do not affect electrical performance or PCB compatibility.

Q: Can I substitute a part with a higher operating temperature range?

A: Yes. Parts with extended upper temperature limits (SMAJ33A-TP to 175°C, SMA6J33A-TR to 175°C) are suitable replacements when the original -65 to 150°C range is not a constraint. Extended temperature capability provides additional design margin for high-temperature environments.

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