SAC18 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SAC18 is an active Littelfuse Transient Voltage Suppressor (TVS) diode designed for general-purpose transient protection applications. This unidirectional zener diode features an 18V reverse standoff voltage with a 28.8V maximum clamping voltage and 15A peak pulse current capability in a through-hole DO-204AC (DO-15) axial package. The part is ROHS3 compliant and rated for operating temperatures from -55°C to 175°C. Equivalent substitute parts are identified to provide design flexibility, inventory alternatives, and sourcing options while maintaining electrical and mechanical compatibility.

Substiute Parts

SAC18

LittelfuseIn Stock: 3787SAC18 Datasheet

Current PartRFQ

SA18A-E3/54

Vishay General Semiconductor - Diodes DivisionIn Stock: 1715SA18A-E3/54 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SAC18 are qualified based on the following critical electrical and mechanical parameters:

• Voltage - Reverse Standoff (Typ): 18V
• Voltage - Breakdown (Min): 20V
• Voltage - Clamping (Max) @ Ipp: Within acceptable tolerance range
• Current - Peak Pulse (10/1000µs): Equal to or greater than 15A
• Power - Peak Pulse: 500W minimum
• Operating Temperature Range: -55°C to 175°C (TJ)
• Package / Case: DO-204AC (DO-15) axial through-hole
• Mounting Type: Through Hole
• RoHS Status: ROHS3 Compliant

The SA18A-E3/54 (Vishay General Semiconductor - Diodes Division) meets all substitution criteria with compatible electrical ratings and identical package specifications.

Parameter Comparison

Engineering Selection Recommendations

Both the SAC18 and SA18A-E3/54 are active products with ROHS3 compliance and REACH unaffected status. The SA18A-E3/54 provides equivalent or superior electrical performance with a higher peak pulse current rating (17.1A versus 15A) and marginally higher clamping voltage (29.2V versus 28.8V), both within acceptable operating margins for 18V standoff applications. Both parts are packaged identically in DO-204AC (DO-15) axial through-hole format and support the same operating temperature range. Selection between these parts may be based on inventory availability, lead time, or specific application margin requirements.

Frequently Asked Questions (FAQ)

Q: Can the SA18A-E3/54 be used as a direct replacement for the SAC18?

A: Yes. Both parts share identical reverse standoff voltage (18V), breakdown voltage (20V minimum), and package specifications (DO-204AC DO-15 axial through-hole). The SA18A-E3/54 offers higher peak pulse current (17.1A) and comparable clamping voltage performance, making it electrically compatible for general-purpose transient protection applications.

Q: What are the key differences between these two parts?

A: The primary differences are manufacturer (Littelfuse versus Vishay) and peak pulse current rating (15A versus 17.1A). The SA18A-E3/54 provides additional current margin. Clamping voltage is slightly higher (29.2V versus 28.8V), which remains within acceptable tolerance for 18V standoff applications.

Q: Are both parts suitable for the same operating temperature range?

A: Yes. Both the SAC18 and SA18A-E3/54 are rated for -55°C to 175°C junction temperature operation, ensuring compatibility across identical thermal environments.

Q: Do both parts meet the same compliance standards?

A: Yes. Both parts are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99 with identical HTSUS codes (8541.10.0080).

Q: Can these parts be used interchangeably on the same PCB without layout modifications?

A: Yes. Both parts use identical DO-204AC (DO-15) axial through-hole packaging, allowing direct PCB footprint compatibility without layout changes.