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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

Diodes Incorporated SB120-B

Name: SB120-B
Brand: Diodes Incorporated
SKU: SB120-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SB120-B

Manufacturer:: Diodes Incorporated

Category:: Single Diodes

Package:: DO-204AL, DO-41, Axial

Datasheet:: SB120-B.pdf

Description:: DIODE SCHOTTKY 20V 1A DO41

Quantity:: RFQ Add To RFQ list

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Inventory:7,321

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Product details

Overview

SB120-B from Diodes Incorporated is a 1.0A, 20V peak repetitive reverse voltage Schottky barrier rectifier in DO-41 plastic package, featuring 0.50V forward voltage at 1.0A, 40A non-repetitive surge capability, and -65°C to +125°C operating temperature range. It is used for polarity protection and low-voltage freewheeling in DC-DC converters.

For engineers reviewing the SB120-B datasheet, SB120-B pinout, SB120-B application, or SB120-B equivalent, key selection criteria include forward voltage drop, thermal resistance (R_JL = 15°C/W), surge rating, RoHS-compliant tin-plated leads, and DO-41 mechanical compatibility with through-hole PCB layouts.

Technical Context

This Schottky rectifier uses a guard-ringed die construction to enhance transient robustness without compromising low V_F. Its unidirectional conduction supports half-wave rectification in single-phase AC/DC stages and DC-side flyback energy clamping.

Designed for high-frequency switching environments, it exhibits low junction-to-lead thermal resistance (15°C/W) and typical capacitance of <100pF at 50mV_p-p, 1MHz - enabling fast recovery and minimal switching loss in 100kHz–500kHz power stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	20 V - Maximum reverse blocking voltage before breakdown; defines safe operation in 12V rail polarity protection.
I_O	1.0 A - Continuous average forward current at 9.5mm lead length; derated to ~0.6A at +100°C ambient.
V_FM	0.50 V @ 1.0A - Low conduction loss improves efficiency in battery-powered 3.3V/5V systems.
I_FSM	40 A - Peak surge withstand for 8.3ms half-sine; supports inrush limiting in adapter input stages.
R_JL	15 °C/W - Junction-to-lead thermal resistance enables direct heat transfer to PCB copper pour or heatsinked lead.
T_j Range	-65°C to +125°C - Wide operational envelope suitable for automotive under-hood and industrial control enclosures.

Pinout & Package

DO-41 plastic package: axial-leaded, molded black epoxy case, UL 94V-0 rated, 0.3g mass, cathode band marked on body. Leads are bright tin-plated, solderable per MIL-STD-202 Method 208.

Pin/Terminal	Circuit Role	Design Meaning
Anode (unmarked end)	Forward current entry point	Connected to lower-potential side (e.g., ground or return path) in reverse polarity protection.
Cathode (banded end)	Forward current exit / reverse blocking terminal	Connected to positive supply rail; blocks reverse current during fault or hot-swap events.

Key Features

Feature	Design Value
Guard-ringed Schottky die	Improves ESD and surge immunity without increasing V_F, critical for unregulated input interfaces.
Low V_F (0.50V @ 1A)	Reduces power dissipation by >30% vs. standard PN rectifiers, easing thermal design in compact adapters.
40A I_FSM	Withstands capacitor-charging surges in offline SMPS front-ends without derating external fusing.
RoHS-compliant tin plating	Enables lead-free reflow and wave soldering while maintaining wetting reliability on OSP and ENIG finishes.

Applications

USB Power Delivery Input Protection

Industrial PLC Digital Input Stage

Use Scenario: Prevents damage from reversed USB-C cable insertion in 5V PD sink designs.

IC Role / Device Role / Timing Role: Unidirectional polarity guard placed between connector and buck converter input.

Use Value: 0.50V V_F limits voltage drop to <2.5% of 5V rail, preserving regulation margin under full load.

Use Scenario: Protects 24V digital input circuitry from field-wiring reversal in factory automation I/O modules.

IC Role / Device Role / Timing Role: Series-blocking rectifier on dry-contact input path prior to optocoupler interface.

Use Value: -65°C to +125°C rating ensures reliable operation inside sealed DIN-rail enclosures with no forced airflow.

DC-DC Converter Freewheeling Diode

Low-Voltage Battery Backup Path

Use Scenario: Provides flyback current path in 300kHz synchronous buck converter with 3.3V output.

IC Role / Device Role / Timing Role: Asynchronous freewheeling element replacing high-side MOSFET body diode in cost-sensitive designs.

Use Value: 15°C/W R_JL allows direct thermal coupling to ground plane, eliminating need for thermal vias in 2-layer PCBs.

Use Scenario: Enables automatic switchover between main Li-ion cell and backup coin cell in portable medical sensors.

IC Role / Device Role / Timing Role: OR-ing diode isolating two independent 3.0–3.6V sources with minimal dropout.

Use Value: 0.50V forward drop preserves >90% of backup cell energy versus 0.7V silicon alternatives.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky rectifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SB120-A	Same electrical specs; packaged in 5K ammo pack instead of 1K bulk.	No functional difference; suited for automated pick-and-place rather than manual prototyping.	Select SB120-A for SMT line integration; SB120-B for lab evaluation or low-volume hand assembly.
1N5817	Higher V_F (0.45V min, typically 0.55V @ 1A); same DO-41 package and 20V V_RRM.	Slightly higher conduction loss reduces efficiency in thermally constrained battery apps.	Choose 1N5817 only if SB120-B is unavailable; verify thermal margin due to ~10% higher V_F at 1A.

Compared with SB120-A and 1N5817, SB120-B offers identical performance to SB120-A in bulk form-ideal for bench testing-while outperforming 1N5817 in forward voltage and surge robustness, making it preferable for high-reliability 12V/24V industrial power rails.

Availability

SB120-B is available at Aetrix Electronics and suitable for USB power delivery input protection, industrial PLC digital input stages, DC-DC converter freewheeling, and low-voltage battery backup paths requiring stable component supply and consistent DO-41 mechanical fit.

Supply support for SB120-B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.

The SBxx0 series belongs to Diodes' general-purpose Schottky rectifier product line, engineered for cost-sensitive, high-efficiency power conversion in consumer, industrial, and computing applications where low V_F and surge resilience are essential.

FAQ

What is the maximum junction temperature for SB120-B?

The SB120-B has a maximum junction temperature of +125°C under continuous operation, with storage temperature extending to +150°C. Derating begins above +25°C ambient per Figure 1, where average forward current drops linearly to zero at +125°C case temperature for resistive loads.

Is SB120-B suitable for surface-mount assembly?

No - SB120-B uses the DO-41 axial-leaded package, designed exclusively for through-hole mounting. It is not compatible with reflow or wave soldering processes intended for SMT components. For surface-mount equivalents, consider Diodes' AP120W (SOD-123) or SBM120 (SMC) variants.

Does SB120-B have a specified reverse recovery time?

No - as a Schottky barrier device, SB120-B has no minority-carrier storage delay and therefore no defined reverse recovery time (t_rr). Its switching is limited only by junction capacitance (~60pF at 4V), enabling use in frequencies up to several hundred kHz without commutation loss.

Can SB120-B replace a 1N4001 in a 12V power supply?

Yes, but with caveats: SB120-B offers lower V_F (0.50V vs. ~0.95V) and faster switching, improving efficiency and reducing heat. However, its 20V V_RRM is lower than 1N4001's 50V - verify that peak reverse voltage in your circuit remains below 20V to avoid breakdown.

SB120-B Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: DO-204AL, DO-41, Axial

Packaging:: Bulk

Product Status:: Obsolete

Technology:: Schottky

Voltage - DC Reverse (Vr) (Max):: 20 V

Current - Average Rectified (Io):: 1A

Voltage - Forward (Vf) (Max) @ If:: 500 mV @ 1 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: -

Current - Reverse Leakage @ Vr:: 500 µA @ 20 V

Capacitance @ Vr, F:: -

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-41

Operating Temperature - Junction:: -65°C ~ 125°C

SB120-B FAQ

1.How can I place an order for SB120-B through Aetrix?

Please submit a Request for Quotation (RFQ) for SB120-B on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SB120-B reliable?

The price and inventory of SB120-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SB120-B is usually 5 days.

3.What payment methods are accepted for SB120-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SB120-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SB120-B?

SB120-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SB120-B order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SB120-B?

For technical support, including SB120-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SB120-B requirements.

6.How does Aetrix verify that SB120-B is sourced from the original manufacturer or authorized distributors?

All SB120-B products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SB120-B meets industry standards.

7.What is the process for return or replacement of SB120-B?

All SB120-B units undergo pre-shipment inspection (PSI). If there is an issue with SB120-B, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SB120-B part is unused and in its original packaging.

Return procedure for SB120-B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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