SMP18-M3/84A Equivalent & Substitute Parts

Part Overview

The SMP18-M3/84A is a unidirectional Transient Voltage Suppressor (TVS) diode from Vishay General Semiconductor - Diodes Division, designed for general-purpose transient voltage protection applications. This component features a 18V reverse standoff voltage with 32.2V maximum clamping voltage and 12.4A peak pulse current capability in a surface-mount DO-220AA package.

The SMP18-M3/84A is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this TVS diode specification.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	18	V
Voltage - Breakdown (Min)	20	V
Voltage - Clamping (Max) @ Ipp	32.2	V
Current - Peak Pulse (10/1000µs)	12.4	A
Power - Peak Pulse	400	W
Operating Temperature Range	-55 to 150	°C (TJ)
Package / Case	DO-220AA	-
Mounting Type	Surface Mount	-
Type	Zener	-
Unidirectional Channels	1	-

Substitute Part Grouping Explanation

Substitution eligibility for the SMP18-M3/84A is determined by strict alignment of the following electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 18V
Voltage - Breakdown (Min): 20V
Package / Case: DO-220AA (surface mount)
Mounting Type: Surface Mount
Type: Zener, Unidirectional
Unidirectional Channels: 1
Operating Temperature Range: -55°C to 150°C (TJ)
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts must maintain identical standoff voltage, breakdown voltage, package configuration, and thermal operating range. Variations in clamping voltage and peak pulse current are permissible within the same product family when the core voltage protection parameters remain constant.

Parameter Comparison

Parameter	SMP18-M3/84A (Main)	SMP18-M3/85A	SMP18A-M3/84A
Manufacturer	Vishay General Semiconductor - Diodes Division	Vishay General Semiconductor - Diodes Division	Vishay General Semiconductor - Diodes Division
Category	Transient Voltage Suppressors (TVS)	Transient Voltage Suppressors (TVS)	Transient Voltage Suppressors (TVS)
Series	TransZorb®, eSMP®	TransZorb®, eSMP®	TransZorb®, eSMP®
Type	Zener	Zener	Zener
Unidirectional Channels	1	1	1
Voltage - Reverse Standoff (Typ)	18V	18V	18V
Voltage - Breakdown (Min)	20V	20V	20V
Voltage - Clamping (Max) @ Ipp	32.2V	32.2V	29.2V
Current - Peak Pulse (10/1000µs)	12.4A	12.4A	13.7A
Power - Peak Pulse	400W	400W	400W
Operating Temperature	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	DO-220AA	DO-220AA	DO-220AA
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
Product Status	Obsolete	Active	Active

Engineering Selection Recommendations

SMP18-M3/85A is the primary substitute for SMP18-M3/84A. Both parts maintain identical electrical specifications for voltage protection parameters (18V standoff, 20V breakdown minimum, 32.2V clamping maximum) and thermal operating range. The SMP18-M3/85A is currently in active production status, ensuring supply chain availability. Both parts carry ROHS3 compliance and REACH unaffected status, meeting regulatory requirements for new designs and ongoing production.

SMP18A-M3/84A is an alternative substitute with compatible core voltage protection parameters (18V standoff, 20V breakdown minimum) but differs in clamping voltage (29.2V maximum) and peak pulse current (13.7A). This part is available in Tape & Reel packaging and maintains active product status. Selection of SMP18A-M3/84A requires confirmation that the lower clamping voltage (29.2V versus 32.2V) and higher peak pulse current (13.7A versus 12.4A) are acceptable for the target application circuit.

Frequently Asked Questions (FAQ)

Q: Can SMP18-M3/85A be used as a direct replacement for SMP18-M3/84A?

A: Yes. SMP18-M3/85A maintains identical voltage protection specifications (18V standoff, 20V breakdown, 32.2V clamping) and thermal operating range (-55°C to 150°C). Both use DO-220AA surface-mount packaging. The primary difference is product status: SMP18-M3/85A is active production while SMP18-M3/84A is obsolete.

Q: What is the difference between SMP18-M3/84A and SMP18A-M3/84A?

A: Both parts share the same 18V standoff and 20V breakdown voltage specifications. The key differences are clamping voltage (SMP18-M3/84A: 32.2V maximum; SMP18A-M3/84A: 29.2V maximum) and peak pulse current (SMP18-M3/84A: 12.4A; SMP18A-M3/84A: 13.7A). SMP18A-M3/84A is supplied in Tape & Reel packaging.

Q: Are all three parts compatible with the same PCB footprint?

A: Yes. All three parts use the DO-220AA surface-mount package, ensuring mechanical and electrical compatibility with existing PCB designs. Packaging format differs (SMP18A-M3/84A is supplied in Tape & Reel; others are standard packaging), but the component footprint remains identical.

Q: Do all substitute parts meet the same regulatory compliance standards?

A: Yes. SMP18-M3/85A and SMP18A-M3/84A both carry ROHS3 compliance, REACH unaffected status, and MSL 1 (Unlimited) moisture sensitivity rating, matching the original SMP18-M3/84A specifications.

Q: Which substitute should be selected for new designs?

A: SMP18-M3/85A is recommended for new designs requiring identical electrical performance to the original SMP18-M3/84A. It maintains active production status and identical voltage protection parameters. SMP18A-M3/84A may be selected if the application circuit can accommodate the lower clamping voltage and higher peak pulse current specifications.

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