SB120-B Equivalent & Substitute Parts

Part Overview

The SB120-B is a Schottky rectifier diode manufactured by Diodes Incorporated, rated for 20 V DC reverse voltage and 1 A average rectified current in a DO-41 through-hole package. This component is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and procurement continuity. The SB120-B serves applications requiring fast recovery Schottky diode performance in compact axial packaging.

Substiute Parts

SB120-B

Diodes IncorporatedIn Stock: 733SB120-B Datasheet

Current PartRFQ

1N5817

Microchip TechnologyIn Stock: 392971N5817 Datasheet

MFR RecommendedRFQ

DSB1A20

Microchip TechnologyIn Stock: 917DSB1A20 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the obsolete SB120-B is determined by electrical and mechanical parameter alignment within the Schottky rectifier diode category. The critical parameters governing substitution are:

Electrical Parameters:

• Voltage - DC Reverse (Vr) (Max): 20 V minimum requirement
• Current - Average Rectified (Io): 1 A minimum requirement
• Technology: Schottky type
• Speed: Fast Recovery characteristic (≤ 500 ns, > 200 mA)

Mechanical Parameters:

• Mounting Type: Through Hole
• Package / Case: DO-41 or DO-204AL (equivalent axial packages)

The substitute parts identified meet or exceed these electrical specifications and share compatible through-hole axial packaging. Substitutes are grouped by their ability to function as direct replacements in circuits designed for the SB120-B.

Parameter Comparison

Engineering Selection Recommendations

DSB1A20 (Primary Substitute)

The DSB1A20 manufactured by Microchip Technology is the primary substitute for the SB120-B. This part maintains electrical equivalence with identical 20 V reverse voltage and 1 A average rectified current ratings. The DSB1A20 shares the same DO-204AL (DO-41) axial through-hole package, ensuring mechanical compatibility. Forward voltage is specified at 600 mV @ 1 A, compared to 500 mV for the SB120-B, representing a 100 mV increase acceptable within typical circuit tolerances. Reverse leakage current is improved at 100 µA @ 20 V versus 500 µA for the original part. The DSB1A20 is classified as Active product status, ensuring long-term availability and supply chain continuity. This part is RoHS non-compliant and REACH Unaffected.

1N5817 (Alternative Substitute)

The 1N5817 manufactured by Microchip Technology is an alternative substitute with higher current rating of 5 A, exceeding the 1 A requirement of the SB120-B. This part provides design margin for applications with potential current transients or future design modifications. The 1N5817 is Active product status. Detailed electrical parameters including reverse voltage, forward voltage, and reverse leakage are not specified in available data. This part is RoHS non-compliant and REACH Unaffected.

Compliance Considerations

The SB120-B is RoHS3 Compliant and REACH Affected. Both substitute parts (DSB1A20 and 1N5817) are RoHS non-compliant and REACH Unaffected. Design teams must evaluate compliance requirements for their specific applications and regulatory jurisdictions before selecting substitutes.

Frequently Asked Questions (FAQ)

Q: Can the DSB1A20 directly replace the SB120-B in existing circuit boards?

A: Yes. The DSB1A20 shares identical electrical ratings (20 V, 1 A) and the same DO-41 axial through-hole package. Pin-to-pin compatibility is maintained. The 100 mV increase in forward voltage drop is within acceptable operating margins for most applications.

Q: What is the difference between the 1N5817 and DSB1A20 substitutes?

A: The 1N5817 is rated for 5 A average rectified current, providing higher current capacity than the 1 A requirement of the SB120-B. The DSB1A20 maintains the original 1 A rating. Both are Schottky rectifiers in through-hole packages. The 1N5817 is suitable for applications requiring design margin or higher current capability. The DSB1A20 is the closer electrical equivalent.

Q: Are there package compatibility concerns when substituting?

A: No. Both substitute parts use DO-41 axial through-hole packaging, identical to the SB120-B. Mechanical fit and board layout remain unchanged.

Q: Why is the SB120-B classified as obsolete?

A: The SB120-B is no longer manufactured by Diodes Incorporated. Active alternatives from other manufacturers provide equivalent or superior performance, making the original part obsolete in the market.

Q: What is the significance of the reverse leakage current difference between SB120-B and DSB1A20?

A: The DSB1A20 exhibits lower reverse leakage current (100 µA @ 20 V) compared to the SB120-B (500 µA @ 20 V). Lower leakage current reduces power dissipation in reverse bias conditions and improves circuit efficiency. This represents an improvement in the substitute part.

Q: How do compliance differences affect part selection?

A: The SB120-B is RoHS3 Compliant, while both substitutes are RoHS non-compliant. Applications subject to RoHS regulations must verify that substitute parts meet applicable compliance requirements before implementation. REACH status differs between the original part (REACH Affected) and substitutes (REACH Unaffected), requiring evaluation for specific regulatory jurisdictions.

Q: Can the 1N5817 be used in applications designed for 1 A operation?

A: Yes. The 1N5817 is rated for 5 A, exceeding the 1 A design requirement. It operates safely at lower current levels. However, detailed electrical parameters for the 1N5817 are not fully specified, so the DSB1A20 is recommended for applications requiring precise parameter matching.