S1AL Equivalent & Substitute Parts Reference

Part Overview

The S1AL is a 1A, 50V standard recovery rectifier diode manufactured by Taiwan Semiconductor Corporation in SOD-123 surface mount packaging. This component is classified as not for new designs, indicating it has been superseded in the manufacturer's product portfolio. The S1AL serves general-purpose rectification applications requiring moderate voltage and current ratings with standard recovery characteristics.

Due to its discontinued status for new designs, identifying functionally compatible substitute components is essential for ongoing production support, maintenance applications, and legacy system repairs where the original part specification must be maintained or enhanced.

Substiute Parts

S1AL

Taiwan Semiconductor CorporationIn Stock: 15161S1AL Datasheet

Current PartRFQ

S1DLW

Taiwan Semiconductor CorporationIn Stock: 21207S1DLW Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the S1AL is determined by the following critical parameters:

Current Rating: The substitute must support a minimum average rectified current (Io) of 1A to maintain functional equivalence in rectification applications.

Voltage Rating: The substitute must support a minimum reverse voltage (Vr) rating of 50V. Substitutes with higher voltage ratings are acceptable as they provide enhanced overvoltage margin without compromising circuit performance.

Forward Voltage Characteristics: The substitute must maintain forward voltage (Vf) characteristics at or below 1.1V @ 1A to ensure compatible voltage drop behavior in rectification circuits.

Recovery Speed: The substitute must maintain standard recovery characteristics (>500ns, >200mA) to preserve switching behavior in the application.

Package Compatibility: The substitute must be surface mount technology compatible. Variations in package case designation (SOD-123 versus SOD-123W) are acceptable provided the component footprint and lead configuration support the existing PCB layout.

Environmental Compliance: The substitute must maintain ROHS3 compliance and MSL rating of 1 to ensure regulatory and manufacturing process compatibility.

The S1DLW meets all substitution criteria while providing enhanced voltage rating (200V versus 50V) and improved reverse leakage characteristics.

Parameter Comparison

Engineering Selection Recommendations

S1DLW Selection Basis: The S1DLW is the manufacturer-recommended substitute for the S1AL. This substitution is supported by the following engineering factors:

Functional Equivalence: Both components share identical current ratings (1A), forward voltage characteristics (1.1V @ 1A), and recovery speed classifications (standard recovery >500ns). These parameters ensure direct functional replacement in rectification circuits.

Enhanced Voltage Margin: The S1DLW provides a 200V reverse voltage rating compared to the S1AL's 50V rating. This four-fold increase in voltage capability provides superior overvoltage protection and margin in applications where the original 50V specification is adequate.

Improved Leakage Performance: The S1DLW demonstrates superior reverse leakage characteristics (1µA @ 200V) compared to the S1AL (5µA @ 50V), indicating enhanced junction quality and long-term reliability.

Active Product Status: The S1DLW maintains active product status with the manufacturer, ensuring continued availability and manufacturing support. The S1AL's discontinued status for new designs necessitates transition to an active alternative.

Regulatory Compliance: Both components maintain identical ROHS3 compliance and MSL rating of 1, ensuring compatibility with current manufacturing processes and environmental regulations.

Package Consideration: The S1DLW uses SOD-123W packaging versus the S1AL's SOD-123 packaging. Both are surface mount configurations with compatible footprints for standard PCB layouts, though physical package dimensions should be verified against specific PCB design constraints.

Frequently Asked Questions (FAQ)

Q: Can the S1DLW directly replace the S1AL in existing designs?

A: Yes. The S1DLW provides functional equivalence across all critical rectification parameters: 1A current rating, 1.1V forward voltage @ 1A, and standard recovery speed characteristics. The enhanced 200V voltage rating provides additional margin without affecting circuit operation at the original 50V specification level.

Q: What is the significance of the voltage rating difference between S1AL (50V) and S1DLW (200V)?

A: The S1DLW's higher voltage rating indicates superior junction design and manufacturing process. In applications where the circuit operates at or below 50V, the S1DLW provides enhanced overvoltage protection. The forward voltage drop and current handling remain identical, so circuit performance is not affected by this parameter difference.

Q: Are there package compatibility concerns when substituting S1AL with S1DLW?

A: Both components use surface mount technology in similar package families (SOD-123 and SOD-123W). Physical package dimensions and lead configurations should be verified against the specific PCB layout to ensure mechanical compatibility. Standard PCB designs typically accommodate both package variants without modification.

Q: Why is the S1AL marked as "Not For New Designs"?

A: This designation indicates the manufacturer has superseded the S1AL in their product portfolio. The S1DLW represents the active replacement offering equivalent or enhanced performance characteristics. For ongoing production and maintenance applications, the S1DLW ensures continued manufacturer support and component availability.

Q: How do the reverse leakage characteristics compare between these components?

A: The S1AL exhibits 5µA reverse leakage @ 50V, while the S1DLW exhibits 1µA reverse leakage @ 200V. The S1DLW's lower leakage at a higher voltage rating indicates superior junction quality. This improvement reduces standby current consumption and enhances long-term reliability in applications sensitive to leakage current.

Q: Are the environmental operating ranges identical?

A: Yes. Both components operate across the identical junction temperature range of -55°C to 175°C, ensuring compatible thermal performance in all operating environments.

Q: What compliance certifications apply to both components?

A: Both the S1AL and S1DLW maintain ROHS3 compliance and MSL rating of 1 (unlimited moisture sensitivity level). Both are classified as REACH Unaffected and carry ECCN designation EAR99, ensuring regulatory compatibility across manufacturing and distribution channels.