P6SMB18AT3 Equivalent & Substitute Parts

Part Overview

The P6SMB18AT3 is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by onsemi, rated for 15.3V reverse standoff voltage with 25.2V maximum clamping voltage at peak pulse current. Housed in the DO-214AA (SMB) surface mount package, this component is designed for transient voltage protection in electronic circuits. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	15.3	V
Voltage - Breakdown (Min)	17.1	V
Voltage - Clamping (Max) @ Ipp	25.2	V
Current - Peak Pulse (10/1000µs)	24	A
Power - Peak Pulse	600	W
Operating Temperature Range	-65 to 150	°C (TJ)
Package / Case	DO-214AA, SMB	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the P6SMB18AT3 is determined by strict alignment of electrical and mechanical parameters. The following criteria establish valid equivalency:

Primary Substitution Criteria:

Voltage - Reverse Standoff (Typ): 15.3V
Voltage - Breakdown (Min): 17.1V
Voltage - Clamping (Max) @ Ipp: 25.2V ±0.3V tolerance acceptable
Current - Peak Pulse (10/1000µs): 24A ±15% tolerance acceptable
Power - Peak Pulse: 600W minimum
Package / Case: DO-214AA or SMB equivalent
Type: Unidirectional Zener diode
Unidirectional Channels: 1

Secondary Considerations:

Operating temperature range must encompass or exceed the original specification
RoHS compliance status and moisture sensitivity level (MSL 1 - Unlimited) are maintained across all substitutes
Surface mount mounting type is required

Parts that deviate from these core electrical parameters or package specifications are not direct substitutes and require circuit re-evaluation.

Parameter Comparison

Part Number	Manufacturer	VWM (V)	VBR Min (V)	VC Max (V)	Ipp (A)	Power (W)	Temp Range (°C)	Package	Status
P6SMB18AT3	onsemi	15.3	17.1	25.2	24	600	-65 to 150	DO-214AA, SMB	Obsolete
P6SMB18A	Eaton - Electronics Division	15.3	17.1	25.2	24.2	600	-55 to 150	DO-214AA, SMB	Active
P6SMB18A-M3/52	Vishay General Semiconductor - Diodes Division	15.3	17.1	25.2	23.8	600	-65 to 150	DO-214AA, SMB	Active
P6SMB18A-M3/5B	Vishay General Semiconductor - Diodes Division	15.3	17.1	25.2	23.8	600	-65 to 150	DO-214AA, SMB	Active
1KSMB18A	Taiwan Semiconductor Corporation	15.3	17.1	25.5	39.2	1000	-55 to 175	DO-214AA, SMB	Active
SMBJP6KE18A-TP	Micro Commercial Co	15.3	17.1	25.5	24.2	600	-55 to 175	DO-214AA, SMB	Active
TPSMB18A	Littelfuse Inc.	15.3	17.1	25.5	24.2	600	-65 to 175	DO-214AA, SMB	Active
SM6T18A	STMicroelectronics	15.3	17.1	32.5	123 (8/20µs)	600	-55 to 150	DO-214AA, SMB	Active
SM6T18AY	STMicroelectronics	15.3	17.1	32.5	123 (8/20µs)	600	-55 to 150	DO-214AA, SMB	Active
PTVS16VP1UP,115	Nexperia USA Inc.	16	17.8	26	23.1	600	-55 to 150	SOD-128	Discontinued

Engineering Selection Recommendations

Direct Electrical Equivalents (Recommended Primary Substitutes):

The P6SMB18A (Eaton), P6SMB18A-M3/52 (Vishay), and P6SMB18A-M3/5B (Vishay) provide the closest electrical match to the P6SMB18AT3. All three maintain the 15.3V standoff voltage, 17.1V minimum breakdown voltage, and 25.2V clamping voltage specification. Peak pulse current values (23.8A to 24.2A) fall within acceptable tolerance of the original 24A specification. All are active products with RoHS compliance and unlimited moisture sensitivity rating.

Extended Temperature Range Alternatives:

The TPSMB18A (Littelfuse) offers identical electrical parameters to the primary equivalents while extending the upper operating temperature to 175°C and maintaining the lower limit at -65°C, matching the original part's lower temperature specification. This part is AEC-Q101 qualified for automotive applications.

Higher Performance Alternatives:

The 1KSMB18A (Taiwan Semiconductor Corporation) and SMBJP6KE18A-TP (Micro Commercial Co) maintain core voltage specifications but offer increased peak pulse current (39.2A and 24.2A respectively) and higher power dissipation (1000W and 600W). These parts are suitable for applications requiring enhanced transient protection margin.

Non-Equivalent Parts:

The SM6T18A and SM6T18AY (STMicroelectronics) exhibit significantly higher clamping voltage (32.5V) and peak pulse current (123A at 8/20µs pulse), making them unsuitable as direct substitutes. The PTVS16VP1UP,115 (Nexperia) uses a different package (SOD-128) and has different voltage specifications (16V standoff, 17.8V breakdown), disqualifying it as an equivalent.

Frequently Asked Questions (FAQ)

Q: Can I use the SM6T18A as a substitute for the P6SMB18AT3?

A: No. While both are 15.3V standoff TVS diodes in SMB packages, the SM6T18A has a maximum clamping voltage of 32.5V compared to the P6SMB18AT3's 25.2V specification. This higher clamping voltage may allow excessive voltage transients to reach protected circuitry. The SM6T18A is not a direct equivalent.

Q: What is the difference between P6SMB18A-M3/52 and P6SMB18A-M3/5B?

A: Both parts are manufactured by Vishay and share identical electrical specifications (15.3V standoff, 25.2V clamping, 23.8A peak pulse). The difference lies in packaging configuration: M3/52 uses Tape & Box (TB) packaging, while M3/5B also uses Tape & Box. Both are suitable substitutes for the P6SMB18AT3.

Q: Is the 1KSMB18A a suitable substitute?

A: The 1KSMB18A maintains the required 15.3V standoff and 17.1V breakdown voltages. However, its 25.5V clamping voltage is 0.3V higher than the original specification, and its peak pulse current is 39.2A compared to 24A. This part provides enhanced protection margin and is suitable for applications where higher transient suppression capability is acceptable. Circuit validation is recommended for critical applications.

Q: Why is the PTVS16VP1UP,115 not listed as an equivalent?

A: The PTVS16VP1UP,115 has a 16V reverse standoff voltage and 17.8V minimum breakdown voltage, both higher than the P6SMB18AT3's 15.3V and 17.1V specifications. Additionally, it uses a SOD-128 package rather than DO-214AA (SMB), requiring different PCB footprint and assembly considerations. This part is not electrically or mechanically equivalent.

Q: Can I substitute the P6SMB18A from Eaton for the obsolete onsemi P6SMB18AT3?

A: Yes. The Eaton P6SMB18A is a direct electrical equivalent with matching 15.3V standoff, 17.1V breakdown, and 25.2V clamping voltages. Peak pulse current is 24.2A, within acceptable tolerance of the original 24A. The part is active, RoHS compliant, and available in standard SMB packaging. The only difference is the lower operating temperature limit (-55°C vs. -65°C), which is acceptable for most applications unless extreme cold operation is required.

Q: What packaging options are available for P6SMB18A substitutes?

A: All recommended substitutes use the DO-214AA (SMB) surface mount package, maintaining PCB footprint compatibility with the original P6SMB18AT3. Packaging variants include Cut Tape (CT) & Digi-Reel®, Tape & Reel (TR), and Tape & Box (TB), affecting only supply and handling methods, not electrical or mechanical performance.

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