SMA5C18-TP Equivalent & Substitute Parts

Part Overview

The SMA5C18-TP is a Zener diode rated at 18 V nominal voltage with 3 W maximum power dissipation, manufactured by Micro Commercial Co in the DO-214AC (SMA) surface mount package. This component is classified as obsolete product status. Due to its obsolete classification, identifying equivalent substitute parts with compatible electrical and mechanical specifications is essential for design continuity and procurement planning. Substitute parts must maintain the same voltage rating, power rating, package type, and mounting configuration to ensure direct replacement capability.

Substiute Parts

SMA5C18-TP

Micro Commercial CoIn Stock: 1130SMA5C18-TP Datasheet

Current PartRFQ

3SMAJ5931B-TP

Micro Commercial CoIn Stock: 58763SMAJ5931B-TP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SMA5C18-TP are identified based on the following critical parameters that define functional equivalence:

Primary Matching Criteria:

• Voltage - Zener (Nom): 18 V (exact match required)
• Power - Max: 3 W (exact match required)
• Package / Case: DO-214AC, SMA (exact match required)
• Mounting Type: Surface Mount (exact match required)

Secondary Compatibility Parameters:

• Operating Temperature Range: Must encompass or match the original specification
• RoHS Status: ROHS3 Compliant (regulatory requirement)
• Moisture Sensitivity Level: MSL 1 (Unlimited)

The substitute part 3SMAJ5931B-TP meets all primary matching criteria. Variations in tolerance, impedance, reverse leakage current, and forward voltage are within acceptable ranges for Zener diode substitution in the same voltage and power class.

Parameter Comparison

Engineering Selection Recommendations

3SMAJ5931B-TP as Primary Substitute:

The 3SMAJ5931B-TP is a direct substitute for the obsolete SMA5C18-TP. Both components share identical voltage rating (18 V), power rating (3 W), and package configuration (DO-214AC, SMA surface mount). The substitute part carries active product status, ensuring long-term availability and supply chain continuity.

Compliance Alignment:

Both parts maintain ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, satisfying regulatory and manufacturing requirements. The substitute part includes REACH Unaffected status, providing additional environmental compliance documentation.

Parameter Variations:

The 3SMAJ5931B-TP exhibits improved tolerance (±5% versus ±6.39%), lower impedance (12 Ohms versus 20 Ohms), and tighter reverse leakage specifications. These variations represent performance enhancements within the same functional class and do not preclude direct substitution. The operating temperature range of the substitute (-55°C ~ 150°C) covers the upper portion of the original specification; applications requiring the full -65°C lower limit must be evaluated against actual circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can the 3SMAJ5931B-TP directly replace the SMA5C18-TP in existing designs?

A: Yes. Both components share identical voltage rating (18 V), power rating (3 W), and DO-214AC (SMA) package configuration. Direct PCB-level substitution is supported without layout modifications.

Q: What is the significance of the tolerance difference (±6.39% vs. ±5%)?

A: The substitute part features tighter tolerance, meaning the actual Zener voltage will remain closer to the 18 V nominal specification. This represents an improvement in voltage regulation accuracy and does not create compatibility issues.

Q: Does the lower operating temperature minimum (-55°C vs. -65°C) affect substitution?

A: The substitute part's operating range is -55°C ~ 150°C, which does not extend to -65°C. Applications operating below -55°C ambient or junction temperature must verify circuit requirements against this specification. For standard industrial and commercial temperature ranges, this difference is not limiting.

Q: Why is the impedance lower in the substitute part (12 Ohms vs. 20 Ohms)?

A: Lower impedance indicates improved dynamic response and voltage regulation characteristics. This is a performance enhancement that does not compromise substitution compatibility.

Q: What is the packaging difference between the two parts?

A: The SMA5C18-TP is supplied in standard packaging, while the 3SMAJ5931B-TP is supplied in Tape & Reel (TR) format. Both use the identical DO-214AC (SMA) component package. Tape & Reel packaging is standard for high-volume surface mount assembly and does not affect component performance.

Q: Are both parts RoHS compliant?

A: Yes. Both the SMA5C18-TP and 3SMAJ5931B-TP are ROHS3 compliant, meeting current environmental and regulatory requirements.

Q: What is the inventory status for the substitute part?

A: The 3SMAJ5931B-TP is classified as active product status with 5768 pieces in stock, ensuring reliable procurement availability compared to the obsolete SMA5C18-TP.