P6SMB33AT3G Equivalent & Substitute Parts

Part Overview

The P6SMB33AT3G is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc. in the P6SMB series. This surface mount component is rated for 28.2V reverse standoff voltage with a 45.7V maximum clamping voltage and 13.2A peak pulse current. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	28.2	V
Voltage - Breakdown (Min)	31.4	V
Voltage - Clamping (Max) @ Ipp	45.7	V
Current - Peak Pulse (10/1000µs)	13.2	A
Power - Peak Pulse	600	W
Package / Case	DO-214AA, SMB	—
Operating Temperature Range	-65°C to 150°C	TJ
Type	Zener	—
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution eligibility for the P6SMB33AT3G is determined by the following critical parameters:

Voltage - Reverse Standoff (Typ): 28.2V ± tolerance
Voltage - Clamping (Max) @ Ipp: 45.7V ± tolerance
Current - Peak Pulse (10/1000µs): minimum 13.2A
Package / Case: DO-214AA (SMB) form factor
Unidirectional Channels: 1
Type: Zener diode

Substitute parts are grouped into two categories:

Direct Electrical Equivalents maintain all critical voltage and current parameters within acceptable engineering tolerances, ensuring drop-in replacement capability.

Functional Equivalents meet the core voltage suppression requirements but may exhibit variations in peak pulse current handling or clamping voltage characteristics. These parts are suitable for applications where the specified performance envelope permits minor parameter deviations.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Clamping (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Package	Product Status	Operating Temp (°C)
P6SMB33AT3G	Littelfuse Inc.	28.2	45.7	13.2	600	DO-214AA, SMB	Obsolete	-65 to 150
P6SMB33A	Eaton - Electronics Division	28.2	45.7	13.3	600	DO-214AA, SMB	Active	-55 to 150
1KSMB33A	Taiwan Semiconductor Corporation	28.2	45.7	21.9	1000	DO-214AA, SMB	Active	-55 to 175
SMBJ30A	MDD	30.0	48.4	12.4	600	DO-214AA, SMB	Active	-55 to 150
TPSMB33A	Littelfuse Inc.	28.2	45.7	13.3	600	DO-214AA, SMB	Active	-65 to 175
SM6T33A	STMicroelectronics	28.2	59.0	68.0	600	DO-214AA, SMB	Active	-55 to 150
SM6T33AY	STMicroelectronics	28.2	59.0	68.0	600	DO-214AA, SMB	Active	-55 to 150
SMBJ33A	Good-Ark Semiconductor	33.0	53.3	11.3	600	DO-214AA, SMB	Active	-55 to 150
SMBJP6KE33A-TP	Micro Commercial Co	28.2	45.7	13.3	600	DO-214AA, SMB	Active	-55 to 175

Engineering Selection Recommendations

Primary Substitutes (Direct Electrical Equivalents)

P6SMB33A (Eaton - Electronics Division) and TPSMB33A (Littelfuse Inc.) are direct electrical equivalents with matching 28.2V reverse standoff, 45.7V clamping voltage, and 13.3A peak pulse current. Both are active products with ROHS3 compliance. TPSMB33A extends the operating temperature range to 175°C and carries AEC-Q101 automotive qualification, making it suitable for temperature-critical or automotive applications. P6SMB33A is specified for telecom applications and maintains the -55°C to 150°C operating range.

SMBJP6KE33A-TP (Micro Commercial Co) provides identical electrical parameters with extended temperature range (-55°C to 175°C) and active product status.

Secondary Substitutes (Functional Equivalents with Enhanced Performance)

1KSMB33A (Taiwan Semiconductor Corporation) maintains the 28.2V reverse standoff and 45.7V clamping voltage but provides enhanced current handling at 21.9A and increased power dissipation at 1000W. This part is suitable for applications requiring higher transient energy absorption. Operating temperature extends to 175°C.

Conditional Substitutes (Parameter Deviations)

SM6T33A and SM6T33AY (STMicroelectronics) share the 28.2V reverse standoff voltage but exhibit higher clamping voltage (59V) and significantly higher peak pulse current (68A at 8/20µs pulse). These parts are suitable only where the application circuit can tolerate the elevated clamping voltage. SM6T33AY includes AEC-Q101 automotive qualification.

SMBJ33A (Good-Ark Semiconductor) deviates from the original specification with 33V reverse standoff voltage and 53.3V clamping voltage. This part is not recommended as a direct substitute due to voltage parameter mismatch.

SMBJ30A (MDD) exhibits 30V reverse standoff and 48.4V clamping voltage, representing a marginal deviation from the original 28.2V specification. Selection requires circuit-level validation.

Frequently Asked Questions (FAQ)

Q: Can P6SMB33A be used as a direct replacement for P6SMB33AT3G?

A: Yes. P6SMB33A maintains identical voltage parameters (28.2V reverse standoff, 45.7V clamping) and equivalent current rating (13.3A vs. 13.2A). Both use DO-214AA (SMB) packaging. The primary difference is product status (active vs. obsolete) and operating temperature range (-55°C to 150°C vs. -65°C to 150°C). Verify the lower temperature limit is acceptable for your application.

Q: What is the difference between TPSMB33A and P6SMB33A?

A: Both parts are electrically equivalent with 28.2V reverse standoff and 45.7V clamping voltage. TPSMB33A is manufactured by Littelfuse (same as the original part), extends operating temperature to 175°C, and carries AEC-Q101 automotive qualification. P6SMB33A is manufactured by Eaton and is specified for telecom applications with a -55°C to 150°C operating range.

Q: Why does 1KSMB33A have higher current and power ratings?

A: 1KSMB33A is designed for higher transient energy absorption with 21.9A peak pulse current and 1000W power dissipation compared to the original 13.2A and 600W. The core voltage parameters (28.2V reverse standoff, 45.7V clamping) remain identical. This part is suitable for applications requiring enhanced surge protection but may introduce unnecessary cost if the original ratings are sufficient.

Q: Can SM6T33A replace P6SMB33AT3G?

A: SM6T33A shares the 28.2V reverse standoff voltage but exhibits significantly different clamping characteristics (59V vs. 45.7V) and substantially higher peak pulse current (68A vs. 13.2A). This part is not a direct substitute. Use only if circuit design permits the higher clamping voltage and the application benefits from enhanced current handling.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts are RoHS compliant (ROHS3 or equivalent). Verify specific compliance documentation for your supply chain requirements.

Q: What packaging considerations apply to these substitutes?

A: All substitute parts use DO-214AA (SMB) surface mount packaging, maintaining mechanical and thermal compatibility with the original P6SMB33AT3G. Verify PCB footprint and thermal design specifications with your layout documentation.

Q: Which substitute is recommended for automotive applications?

A: TPSMB33A and SM6T33AY both carry AEC-Q101 automotive qualification. TPSMB33A is the preferred choice as it maintains the original electrical parameters while extending temperature range and providing automotive-grade reliability.

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