SA18A-E3/73 Equivalent & Substitute Parts

Part Overview

The SA18A-E3/73 is a unidirectional Transient Voltage Suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division. This through-hole component operates with an 18V reverse standoff voltage and provides 29.2V maximum clamping voltage, designed for general-purpose transient voltage protection applications. The part is currently active in production with full RoHS3 compliance and unlimited moisture sensitivity rating. Equivalent and substitute parts are identified based on matching electrical performance parameters and compatible package configurations for direct circuit board replacement.

Substiute Parts

SA18A-E3/73

Vishay General Semiconductor - Diodes DivisionIn Stock: 32408SA18A-E3/73 Datasheet

Current PartRFQ

LCE18A

Littelfuse Inc.In Stock: 1007LCE18A Datasheet

MFR RecommendedRFQ

SA18A

Fairchild SemiconductorIn Stock: 7654SA18A Datasheet

MFR RecommendedRFQ

SAC18

LittelfuseIn Stock: 3787SAC18 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SA18A-E3/73 are qualified based on the following critical electrical and mechanical parameters:

Electrical Matching Criteria:

• Voltage - Reverse Standoff (Typ): 18V
• Voltage - Breakdown (Min): 20V
• Voltage - Clamping (Max) @ Ipp: 29.2V (±0.4V tolerance acceptable)
• Unidirectional Channels: 1
• Type: Zener

Mechanical Compatibility Criteria:

• Mounting Type: Through Hole
• Package / Case: DO-204AC (DO-15) or DO-201AA (DO-27) axial packages
• Operating Temperature Range: -55°C ~ 175°C (TJ)

Compliance Requirements:

• RoHS3 Compliant
• Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts may vary in peak pulse current rating and power dissipation capacity while maintaining identical voltage specifications. Peak pulse current differences do not disqualify substitution when the application does not require the higher current rating of alternative parts.

Parameter Comparison

Engineering Selection Recommendations

LCE18A (Littelfuse Inc.): This part maintains identical voltage specifications (18V standoff, 29.2V clamping) with enhanced peak pulse current capability (51A vs. 17.1A) and higher power dissipation (1500W vs. 500W). The DO-201AA package requires mechanical board layout verification for axial lead spacing compatibility. Suitable for applications requiring higher transient energy absorption. Product status is Active with full RoHS3 compliance.

SA18A (Fairchild Semiconductor): This part provides equivalent electrical performance with nearly identical peak pulse current (17.5A vs. 17.1A) and matching DO-204AC package footprint. Direct pin-compatible replacement for SA18A-E3/73. Product status is Obsolete; use only when existing inventory must be maintained or when new stock procurement is not feasible.

SAC18 (Littelfuse): This part matches the DO-204AC package and operating temperature range with slightly lower clamping voltage (28.8V vs. 29.2V) and reduced peak pulse current (15A vs. 17.1A). Acceptable for applications with lower transient energy requirements. Product status is Active with full RoHS3 compliance and unlimited moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can LCE18A replace SA18A-E3/73 in a DO-204AC footprint? A: LCE18A uses a DO-201AA (DO-27) package with different axial lead spacing. Physical board layout modification is required. Electrical substitution is valid; mechanical compatibility must be verified.

Q: What is the difference between SA18A and SA18A-E3/73? A: Both parts share identical electrical specifications (18V standoff, 29.2V clamping, 17.1A peak pulse current) and DO-204AC packaging. SA18A is manufactured by Fairchild Semiconductor and is currently Obsolete. SA18A-E3/73 is the active Vishay equivalent.

Q: Is SAC18 a direct replacement for SA18A-E3/73? A: SAC18 provides compatible voltage protection with 28.8V clamping (0.4V lower than SA18A-E3/73) and 15A peak pulse current (2.1A lower). Direct pin-compatible in DO-204AC package. Suitable for applications not requiring the full 17.1A pulse current specification.

Q: Are all substitute parts RoHS3 compliant? A: Yes. SA18A-E3/73, LCE18A, SA18A, and SAC18 are all ROHS3 Compliant with EAR99 ECCN classification and REACH Unaffected status.

Q: What is the operating temperature range for these TVS diodes? A: All listed parts operate across -55°C to 175°C junction temperature (TJ), suitable for industrial and automotive applications.

Q: Can I use a higher current-rated substitute like LCE18A in place of SA18A-E3/73? A: Yes. Higher peak pulse current and power ratings provide additional design margin. Electrical performance remains equivalent at the specified 18V standoff and 29.2V clamping voltages. Physical package compatibility must be confirmed.