SB120 Equivalent & Substitute Parts

Part Overview

The SB120 is a Schottky rectifier diode rated for 20 V DC reverse voltage and 1 A average rectified current in a through-hole DO-41 package. Manufactured by onsemi, this component is classified as obsolete. Due to its obsolete status, equivalent substitute parts from active manufacturers are necessary to maintain design continuity and ensure long-term component availability for new production and field replacements.

Key Parameters

Parameter	Value
Voltage - DC Reverse (Vr) (Max)	20 V
Current - Average Rectified (Io)	1 A
Voltage - Forward (Vf) (Max) @ If	500 mV @ 1 A
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	500 µA @ 20 V
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial
Operating Temperature - Junction	-65°C ~ 125°C
Technology	Schottky

Substitute Part Grouping Explanation

Substitution of the SB120 is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Matching Parameters:

Voltage - DC Reverse (Vr) (Max): 20 V
Current - Average Rectified (Io): 1 A
Technology: Schottky
Mounting Type: Through Hole
Package / Case: DO-204AL, DO-41, or Axial variants

Acceptable Variation Parameters:

Voltage - Forward (Vf) (Max) @ If: Substitute parts rated at 450 mV @ 1 A are acceptable (lower forward voltage represents improved performance)
Current - Reverse Leakage @ Vr: Substitute parts rated at 1 mA @ 20 V are acceptable (higher leakage remains within acceptable limits for this application class)
Operating Temperature - Junction: Substitute parts with extended or equivalent temperature ranges (-65°C ~ 125°C or -65°C ~ 150°C) are acceptable

All substitute parts listed maintain the fast recovery speed characteristic (≤ 500ns, > 200mA) and are manufactured by active component suppliers with current product status.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf (Max) @ If	Reverse Leakage @ Vr	Package	Product Status	Inventory
SB120	onsemi	20 V	1 A	500 mV @ 1 A	500 µA @ 20 V	DO-41	Obsolete	8430 Pcs
1N5817-TP	Micro Commercial Co	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-41	Active	35772 Pcs
1N5817-T	Diodes Incorporated	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-41	Active	10200 Pcs
1N5817-E3/73	Vishay General Semiconductor - Diodes Division	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-204AL (DO-41)	Active	14877 Pcs
1N5817RLG	onsemi	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	Axial	Active	5334 Pcs
1N5817-AP	Micro Commercial Co	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-41	Active	745 Pcs
1N5817-BP	Micro Commercial Co	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-41	Active	878 Pcs
1N5817G	Microchip Technology	20 V	1 A	450 mV @ 1 A	1 mA @ 20 V	DO-41	Active	1047 Pcs

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

1N5817-TP (Micro Commercial Co): Active product status with highest inventory availability (35772 Pcs). RoHS3 compliant. Cut Tape packaging suitable for automated assembly. Operating temperature range -55°C ~ 125°C meets or exceeds SB120 specifications.
1N5817-E3/73 (Vishay General Semiconductor - Diodes Division): Active product status with substantial inventory (14877 Pcs). RoHS3 compliant. Cut Tape packaging. Operating temperature range -65°C ~ 125°C matches SB120 exactly. MSL rating of 1 (Unlimited) indicates robust moisture handling.
1N5817-T (Diodes Incorporated): Active product status with good inventory (10200 Pcs). RoHS3 compliant. Cut Tape packaging. Operating temperature range -65°C ~ 125°C matches SB120 exactly. Capacitance specification provided (110pF @ 4V, 1MHz).

Secondary Substitutes (Package Variant):

1N5817RLG (onsemi): Active product status from original SB120 manufacturer. Axial package variant rather than DO-41. Suitable for applications where axial lead configuration is acceptable. Operating temperature range -65°C ~ 125°C matches SB120.

Tertiary Substitutes (Limited Inventory):

1N5817-AP and 1N5817-BP (Micro Commercial Co): Active products with lower inventory levels (745 Pcs and 878 Pcs respectively). Bulk packaging. Operating temperature range -55°C ~ 125°C. Reverse recovery time specification provided (10 ns).
1N5817G (Microchip Technology): Active product status with limited inventory (1047 Pcs). Bulk packaging. Extended operating temperature range -65°C ~ 150°C. Capacitance specification not provided.

Selection Criteria:

For new production requiring high-volume availability and automated assembly: 1N5817-TP
For applications requiring exact temperature range matching and RoHS3 compliance: 1N5817-E3/73 or 1N5817-T
For designs utilizing axial lead configuration: 1N5817RLG
For applications with extended temperature requirements: 1N5817G

All listed substitutes maintain electrical equivalence to the SB120 across voltage, current, and switching speed parameters. Forward voltage improvement (450 mV vs. 500 mV) in substitute parts represents enhanced performance characteristics.

Frequently Asked Questions (FAQ)

Q: Can the 1N5817-TP directly replace the SB120 in existing PCB designs?

A: Yes. The 1N5817-TP is electrically and mechanically equivalent to the SB120. Both are rated for 20 V reverse voltage, 1 A average rectified current, and use the DO-41 through-hole package. The improved forward voltage characteristic (450 mV vs. 500 mV) represents superior performance. No circuit modifications are required.

Q: What is the difference between DO-41 and DO-204AL package designations?

A: DO-41 and DO-204AL refer to the same physical package format for axial-lead diodes. These designations are equivalent. The 1N5817-E3/73 is specified as DO-204AL (DO-41), confirming this equivalence.

Q: Why do some substitute parts show higher reverse leakage current (1 mA vs. 500 µA)?

A: The reverse leakage current specification of 1 mA at 20 V in substitute parts remains within acceptable limits for Schottky diode applications in this voltage and current class. This represents a minor variation that does not affect circuit performance in standard rectification applications.

Q: Is the 1N5817RLG suitable as a substitute if my design uses axial leads?

A: Yes. The 1N5817RLG is electrically equivalent to the SB120 and uses an axial lead configuration. It is manufactured by onsemi (the original SB120 manufacturer) and maintains the same 20 V / 1 A ratings and operating temperature range. Select this part only if your PCB layout accommodates axial lead spacing.

Q: What does RoHS3 compliance mean for component selection?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. Most substitute parts listed (1N5817-TP, 1N5817-E3/73, 1N5817-T) are RoHS3 compliant, making them suitable for applications requiring environmental compliance.

Q: Which substitute part has the best long-term availability?

A: The 1N5817-TP demonstrates the highest inventory level (35772 Pcs) and active product status from Micro Commercial Co. This part is recommended for new designs requiring long-term component availability assurance.

Q: Can I use the 1N5817G if my application requires operation above 125°C?

A: Yes. The 1N5817G is rated for operating temperatures up to 150°C, providing a 25°C margin above the SB120 specification. This extended temperature range makes it suitable for high-temperature applications. However, verify that other circuit components also support this temperature range.

Q: What is the significance of Cut Tape (CT) versus Bulk packaging?

A: Cut Tape packaging is supplied on continuous tape and cut to order, suitable for automated pick-and-place assembly in production environments. Bulk packaging is supplied loose, typically used for manual assembly or lower-volume applications. For high-volume manufacturing, select parts with Cut Tape packaging (1N5817-TP, 1N5817-E3/73, 1N5817-T).

Q: Are all listed substitute parts manufactured to the same specification?

A: All listed substitute parts meet the core electrical requirements: 20 V reverse voltage, 1 A average rectified current, fast recovery Schottky technology, and through-hole mounting. Minor variations exist in forward voltage (450 mV vs. 500 mV), reverse leakage (1 mA vs. 500 µA), and operating temperature ranges. These variations represent acceptable performance enhancements or equivalent performance within the Schottky diode product class.

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