P6SMB18AT3G Equivalent & Substitute Parts

Part Overview

The P6SMB18AT3G is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc. in the DO-214AA (SMB) surface mount package. This component is rated for 15.3V reverse standoff voltage with a 25.2V maximum clamping voltage and 24A peak pulse current. The part is currently listed as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for new designs or production continuity.

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	—
Mounting Type	Surface Mount	—
Type	Zener	—
Unidirectional Channels	1	—

Substitute Part Grouping Explanation

Substitution of the P6SMB18AT3G is determined by strict equivalence in the following electrical parameters: reverse standoff voltage (15.3V), breakdown voltage minimum (17.1V), clamping voltage maximum (25.2V ±tolerance), peak pulse current rating (24A nominal), and power dissipation (600W). All substitute parts must maintain the DO-214AA (SMB) surface mount package configuration and unidirectional Zener diode topology. Operating temperature range, RoHS compliance status, and product status (active vs. obsolete) are secondary selection criteria that do not affect electrical interchangeability but influence long-term availability and regulatory compliance.

Parameter Comparison

Part Number	Manufacturer	Vwm (Typ) V	Vbr (Min) V	Vc (Max) V	Ipp (10/1000µs) A	Power W	Temp Range °C	Package	Status
P6SMB18AT3G	Littelfuse Inc.	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
TPSMB18A	Littelfuse Inc.	15.3	17.1	25.5	24.2	600	-65 to 175	DO-214AA, SMB	Active
SM6T18A-M3/52	Vishay General Semiconductor - Diodes Division	15.3	17.1	25.2	24	600	-65 to 150	DO-214AA, SMB	Active
SM6T18A-M3/5B	Vishay General Semiconductor - Diodes Division	15.3	17.1	25.2	24	600	-65 to 150	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
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
SMBJ14A	MDD	14	15.6	23.2	25.9	600	-50 to 150	DO-214AA, SMB	Active

Engineering Selection Recommendations

Direct electrical equivalents to the P6SMB18AT3G are P6SMB18A (Eaton), SM6T18A-M3/52 and SM6T18A-M3/5B (Vishay), and SMBJP6KE18A-TP (Micro Commercial Co). These parts maintain identical or near-identical clamping voltage (25.2V to 25.5V) and peak pulse current specifications (24A to 24.2A) within the 10/1000µs pulse profile. All are RoHS3 compliant and available in active production status.

TPSMB18A (Littelfuse Inc.) provides an extended operating temperature range (-65°C to 175°C) and automotive-grade qualification (AEC-Q101), suitable for applications requiring enhanced thermal performance or automotive certification.

SM6T18A and SM6T18AY (STMicroelectronics) exhibit higher clamping voltage (32.5V) and significantly elevated peak pulse current (123A at 8/20µs pulse profile), making them suitable only for applications where higher transient energy absorption is required. These are not direct substitutes for the standard 24A rating.

SMBJ14A (MDD) operates at a lower reverse standoff voltage (14V) and clamping voltage (23.2V), limiting its use to circuits with lower voltage thresholds. This part is not recommended as a direct substitute.

For production continuity of the obsolete P6SMB18AT3G, P6SMB18A or SM6T18A-M3/52 are the primary recommendations based on electrical equivalence and active availability.

Frequently Asked Questions (FAQ)

Q: Can P6SMB18A directly replace P6SMB18AT3G? A: Yes. P6SMB18A maintains the same reverse standoff voltage (15.3V), breakdown voltage (17.1V), and clamping voltage (25.2V) with equivalent peak pulse current (24.2A). The primary difference is the operating temperature minimum (-55°C vs. -65°C). For applications operating above -55°C, this substitution is electrically and mechanically compatible.

Q: What is the difference between SM6T18A and SM6T18A-M3/52? A: Both parts share identical electrical specifications (15.3V standoff, 25.2V clamping, 24A peak pulse). The designation suffix indicates different manufacturing date codes or tape reel configurations. Electrically, they are equivalent.

Q: Why do SM6T18A and SM6T18AY show higher peak pulse current (123A)? A: These parts use a different pulse profile specification (8/20µs) compared to the standard 10/1000µs profile. The 8/20µs pulse is shorter and higher in amplitude, resulting in higher peak current ratings. They are not direct substitutes unless the application specifically requires this pulse profile.

Q: Is SMBJ14A a suitable substitute? A: No. SMBJ14A operates at 14V reverse standoff and 23.2V clamping voltage, which is below the P6SMB18AT3G specification of 15.3V and 25.2V. Using this part in a circuit designed for 15.3V standoff voltage will result in premature device activation and circuit malfunction.

Q: Are all substitute parts available in the same SMB package? A: Yes. All listed substitute parts use the DO-214AA (SMB) surface mount package, ensuring mechanical and footprint compatibility with the original P6SMB18AT3G design.

Q: What is the significance of RoHS3 compliance? A: RoHS3 compliance indicates the part meets current European Union Restriction of Hazardous Substances regulations. All listed active substitutes are RoHS3 compliant, ensuring regulatory compatibility for new designs and production.

Q: Should I select TPSMB18A for automotive applications? A: TPSMB18A is qualified to AEC-Q101 automotive standards and operates across -65°C to 175°C, making it suitable for automotive or high-reliability applications. However, this selection depends on application requirements rather than direct electrical equivalence.

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