P6SMB18C Equivalent & Substitute Parts

Part Overview

The P6SMB18C is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This bidirectional Zener diode operates with a reverse standoff voltage of 15.3V and provides clamping at 26.78V with peak pulse current handling of 24.2A. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Reverse Standoff Voltage (Typ)	15.3V
Voltage Breakdown (Min)	16.2V
Voltage Clamping (Max) @ Ipp	26.78V
Current - Peak Pulse (10/1000µs)	24.2A
Power - Peak Pulse	600W
Operating Temperature Range	-55°C ~ 150°C (TJ)
Package / Case	DO-214AA, SMB
Mounting Type	Surface Mount
Type	Zener
Bidirectional Channels	1
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the P6SMB18C is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Reverse Standoff Voltage: 15.3V (fixed)
Voltage Breakdown (Min): 16.2V or higher
Voltage Clamping (Max) @ Ipp: 25.2V to 26.78V range
Current - Peak Pulse (10/1000µs): 23.8A to 24.2A minimum
Power - Peak Pulse: 600W
Package / Case: DO-214AA, SMB (surface mount)
Mounting Type: Surface Mount
Type: Zener, Bidirectional
Operating Temperature: -55°C minimum to 150°C maximum
RoHS Compliance: ROHS3 or equivalent

Substitute parts are grouped into two categories:

Category 1: Direct Electrical Equivalents (Clamping Voltage 25.2V) Parts with clamping voltage of 25.2V represent the closest electrical match to the P6SMB18C. These include variants from Eaton, Vishay, and Littelfuse with identical standoff and breakdown voltages but slightly lower clamping voltage, acceptable within the P6SMB series tolerance band.

Category 2: Alternative Manufacturer Variants (Clamping Voltage 32.5V) The SM6T18CA from STMicroelectronics operates at 32.5V clamping voltage, representing a higher voltage variant within the same 15.3V standoff class. This part is suitable only for applications where higher clamping voltage is acceptable.

Parameter Comparison

Part Number	Manufacturer	Reverse Standoff (Typ)	Breakdown (Min)	Clamping (Max) @ Ipp	Peak Pulse Current	Power - Peak Pulse	Operating Temp	Package	Product Status	RoHS Status
P6SMB18C	Littelfuse Inc.	15.3V	16.2V	26.78V	24.2A	600W	-55°C ~ 150°C	DO-214AA, SMB	Obsolete	ROHS3
P6SMB18CA	Eaton - Electronics Division	15.3V	17.1V	25.2V	24.2A	600W	-55°C ~ 150°C	DO-214AA, SMB	Active	RoHS
SZP6SMB18CAT3G	Littelfuse Inc.	15.3V	17.1V	25.2V	24A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
P6SMB18CA-E3/52	Vishay General Semiconductor	15.3V	17.1V	25.2V	23.8A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
P6SMB18CA-E3/5B	Vishay General Semiconductor	15.3V	17.1V	25.2V	23.8A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
P6SMB18CA-M3/52	Vishay General Semiconductor	15.3V	17.1V	25.2V	23.8A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
P6SMB18CA-M3/5B	Vishay General Semiconductor	15.3V	17.1V	25.2V	23.8A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
P6SMB18CAHE3_A/H	Vishay General Semiconductor	15.3V	17.1V	25.2V	23.8A	600W	-65°C ~ 150°C	DO-214AA, SMB	Obsolete	ROHS3
SM6T18CA	STMicroelectronics	15.3V	17.1V	32.5V	123A (8/20µs)	600W	-55°C ~ 150°C	DO-214AA, SMB	Active	ROHS3
SM6T18CA-E3/5B	Vishay General Semiconductor	15.3V	17.1V	25.2V	24A	600W	-65°C ~ 150°C	DO-214AA, SMB	Active	ROHS3

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

The P6SMB18CA from Eaton and the Vishay variants (P6SMB18CA-E3/52, P6SMB18CA-E3/5B, P6SMB18CA-M3/52, P6SMB18CA-M3/5B) are the preferred substitutes. These parts maintain the 15.3V standoff voltage and 25.2V clamping voltage within acceptable tolerance of the original P6SMB18C specification. All are active products with ROHS3 compliance and identical package geometry (DO-214AA, SMB). The Vishay variants offer extended operating temperature range (-65°C to 150°C) compared to the original part (-55°C to 150°C).

Littelfuse Manufacturer Recommended Substitute:

The SZP6SMB18CAT3G from Littelfuse is the manufacturer-recommended active substitute. It maintains electrical equivalence with 15.3V standoff and 25.2V clamping voltage. This part includes AEC-Q101 automotive qualification and extended temperature range (-65°C to 150°C), making it suitable for automotive and industrial applications requiring higher reliability standards.

Alternative Consideration:

The SM6T18CA from STMicroelectronics operates at 32.5V clamping voltage with significantly higher peak pulse current (123A at 8/20µs pulse). This part is suitable only for applications where higher clamping voltage and current handling are acceptable design parameters. The SM6T18CA-E3/5B from Vishay provides a 25.2V clamping variant of the SM6T series, offering compatibility with the original P6SMB18C electrical specification.

Obsolete Part Note:

The P6SMB18CAHE3_A/H from Vishay is listed as obsolete and should not be selected for new designs despite its electrical equivalence.

Frequently Asked Questions (FAQ)

Q: Can I use P6SMB18CA as a direct replacement for P6SMB18C?

A: Yes. The P6SMB18CA maintains the critical electrical parameters: 15.3V reverse standoff voltage, 17.1V minimum breakdown voltage, and 25.2V clamping voltage. The 1.56V difference in clamping voltage (26.78V vs 25.2V) falls within the P6SMB series tolerance band. Both parts use identical DO-214AA SMB packaging and support the same 600W peak pulse power rating.

Q: What is the difference between the Vishay variants (E3/52, E3/5B, M3/52, M3/5B)?

A: These designations indicate different packaging and tape configurations. The E3 variants use Tape & Reel (TR) packaging, while M3 variants use Tape & Box (TB) packaging. The /52 and /5B suffixes denote different tape specifications. All four variants are electrically identical with 15.3V standoff, 17.1V breakdown, and 25.2V clamping voltage. Selection depends on procurement and assembly requirements.

Q: Why does SM6T18CA have higher peak pulse current (123A vs 24.2A)?

A: The SM6T18CA uses an 8/20µs pulse definition, which differs from the 10/1000µs pulse specification used for other parts listed. These represent different transient event profiles. The SM6T18CA is suitable only if your application requires the higher current handling capability and accepts the 32.5V clamping voltage.

Q: Is the extended temperature range (-65°C to 150°C) of Vishay and Littelfuse variants important?

A: The extended lower temperature limit (-65°C vs -55°C) provides additional margin for applications operating in cold environments. For most general-purpose applications operating within -55°C to 150°C, this difference is not critical. However, automotive and industrial applications benefit from the extended range.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance or equivalent RoHS certification, matching the original P6SMB18C specification.

Q: Can I mix different manufacturers in the same design?

A: Yes. All substitute parts maintain the same electrical specifications (15.3V standoff, 25.2V clamping, 600W power rating) and identical DO-214AA SMB package geometry. They are mechanically and electrically interchangeable within the specified parameter ranges.

Q: Should I select the Littelfuse SZP6SMB18CAT3G for new designs?

A: The SZP6SMB18CAT3G is the manufacturer-recommended active substitute from Littelfuse. It is suitable for new designs, particularly those requiring AEC-Q101 automotive qualification or extended operating temperature range. For general-purpose applications, any of the active substitutes listed are acceptable.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message