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Diodes Incorporated SB140-B
- Part No.:
- SB140-B
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
SB140-B.pdf
- Description:
- DIODE SCHOTTKY 40V 1A DO41
- Quantity:
- Payment:
- Shipping:
Inventory:6,736
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Product details
Overview
SB140-B from Diodes Incorporated is a 1.0A, 40V peak repetitive reverse voltage Schottky barrier rectifier in DO-41 plastic package, featuring low forward voltage drop (0.50 V @ 1.0 A), high surge capability (40 A peak), and RoHS-compliant bright tin-plated leads. It is used for polarity protection and free-wheeling in low-voltage DC/DC converters and 12 V automotive auxiliary circuits.
For engineers reviewing the SB140-B datasheet, SB140-B pinout, SB140-B application, or SB140-B equivalent, key selection criteria include forward voltage at rated current, thermal resistance (15 °C/W junction-to-lead), surge rating, reverse leakage at 100 °C (5.0 mA), and DO-41 mechanical compatibility with through-hole PCB layouts.
Technical Context
This Schottky rectifier uses a guard ring die construction to enhance transient immunity and reduce reverse recovery charge. Its low VF and fast switching enable high-efficiency operation in 20–100 kHz switching power supplies without snubbers.
Thermal design relies on lead conduction: junction-to-lead resistance is 15 °C/W, while junction-to-ambient is 50 °C/W at 9.5 mm lead length. Operation is specified from –65 °C to +125 °C junction temperature, with storage up to +150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 40 V - Maximum non-repetitive reverse voltage before breakdown; sets safe operating limit in 24 V systems with transients. |
| IF(AV) | 1.0 A - Continuous average forward current under resistive/inductive load; derate 20% for capacitive loads. |
| VF @ 1.0 A | 0.50 V - Low conduction loss enabling >92% efficiency in 5–12 V output buck converters. |
| IFSM | 40 A - Peak surge rating for 8.3 ms half-sine; supports inrush limiting in power supply inputs. |
| RJL | 15 °C/W - Junction-to-lead thermal resistance; enables direct heat sinking via PCB copper pour on cathode/anode leads. |
| IRM @ 100 °C | 5.0 mA - Reverse leakage at max operating temperature; impacts standby power in always-on 12 V modules. |
Pinout & Package
DO-41 plastic package: axial-leaded, molded black epoxy case, UL 94V-0 rated, 0.3 g mass, cathode identified by band. Leads are bright tin-plated and solderable per MIL-STD-202 Method 208.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unbanded end) | Forward current entry point | Connected to lower-potential side (e.g., ground or switch node) in freewheeling paths. |
| Cathode (banded end) | Forward current exit / reverse blocking terminal | Connected to higher-potential rail; reverse voltage applied here during off-state. |
Key Features
| Feature | Design Value |
|---|---|
| Guard ring die construction | Improves ESD and transient robustness without external TVS in 12 V automotive body control modules. |
| Low VF (0.50 V @ 1.0 A) | Reduces conduction loss by ~35% vs. standard silicon rectifiers, lowering thermal stress in sealed enclosures. |
| 40 A IFSM rating | Withstands cold-crank surges in automotive infotainment power rails without fuse coordination issues. |
| RoHS-compliant tin plating | Enables lead-free reflow and wave soldering without whisker risk or intermetallic degradation. |
Applications
| DC/DC Converter Freewheeling Diode | Automotive Polarity Protection |
|---|---|
Use Scenario: Used as catch diode in 12 V input, 3.3 V/2 A synchronous buck converter. IC Role / Device Role / Timing Role: Freewheeling path for inductor current during high-side FET off-time; zero-recovery requirement avoids voltage spikes. Use Value: 0.50 V VF minimizes power loss (0.5 W vs. 1.1 W for 1N4007), reducing heatsink need in compact modules. | Use Scenario: Installed in series with battery feed to telematics control unit (TCU) to prevent damage from reverse battery connection. IC Role / Device Role / Timing Role: Unidirectional current gate; blocks reverse polarity while conducting normal 12 V supply with minimal dropout. Use Value: 40 V VRRM exceeds ISO 7637-2 pulse 5a (−100 V/100 ms), ensuring survival during jump-start faults. |
| Low-Voltage AC/DC Adapter Output | Industrial Sensor Power Rectification |
Use Scenario: Output rectifier in 24 VAC-to-12 VDC wall adapter for PoE-powered switches. IC Role / Device Role / Timing Role: Half-wave rectifier feeding bulk capacitor; operates at 50/60 Hz with low conduction loss. Use Value: 1.0 A IF(AV) and 40 A IFSM handle capacitor charging surges without derating beyond 125 °C Tj limit. | Use Scenario: Rectifies 24 VAC signal from proximity sensor to power internal logic circuitry. IC Role / Device Role / Timing Role: Signal-level AC-to-DC conversion; must operate reliably at –40 °C ambient in factory-floor enclosures. Use Value: –65 °C to +125 °C operating range and <0.5 mA IRM at 25 °C ensure stable biasing across industrial temperature extremes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Schottky rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SB140-T | Same electrical specs; supplied in 5K tape-and-reel (13-inch) instead of 1K bulk. | Optimized for automated SMT placement with carrier tape; not suitable for manual prototyping or low-volume hand-soldering. | Select SB140-T for high-volume production lines using pick-and-place machines. |
| SS14 (DO-214AA) | Same 40 V VRRM and 1.0 A IF(AV), but surface-mount SMB package; VF = 0.55 V @ 1.0 A; RJA = 75 °C/W. | Requires PCB redesign for SMD footprint; better suited for space-constrained consumer electronics vs. through-hole industrial controls. | Choose SS14 only when board area is constrained and thermal management allows higher RJA. |
Compared with SB140-B, SB140-T offers identical performance in automated assembly, while SS14 trades axial-leaded ease-of-use for smaller footprint at the cost of higher thermal resistance and layout change overhead.
Availability
SB140-B is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, and low-voltage DC/DC converter designs requiring stable component supply and long-term obsolescence planning.
Supply support for SB140-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 targets cost-sensitive, high-reliability rectification in automotive, industrial, and consumer power supplies where low VF and surge robustness are critical.
FAQ
What is the maximum allowable junction temperature for continuous operation?
The SB140-B is rated for continuous operation up to +125 °C junction temperature. Derating begins above this point per Figure 1, where average forward current drops linearly to zero at +150 °C. Thermal design must maintain Tj ≤ 125 °C under worst-case ambient and power dissipation conditions.
Can SB140-B be used in place of a 1N4007 in a 12 V power supply?
Yes, but only if reverse voltage remains below 40 V. The SB140-B has lower VF (0.50 V vs. ~1.1 V) and faster switching, improving efficiency and eliminating reverse recovery noise. However, its 40 V VRRM is insufficient for 120 VAC rectification-1N4007's 1000 V rating makes it unsuitable for direct substitution in line-voltage applications.
Is SB140-B compatible with lead-free reflow soldering processes?
Yes. Its bright tin-plated leads meet J-STD-020C moisture sensitivity Level 1 and are qualified for lead-free reflow profiles with peak temperatures up to 260 °C. No pre-baking is required, and solder wettability complies with MIL-STD-202 Method 208.
How does the guard ring die construction improve reliability?
The guard ring reduces electric field crowding at the PN junction edge, suppressing avalanche-induced localized heating and preventing premature breakdown under transient overvoltage. This extends lifetime in automotive environments subject to ISO 7637-2 pulses and improves consistency in high-volume manufacturing.
SB140-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):
- 40 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 @ 40 V
- Capacitance @ Vr, F:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-41
- Operating Temperature - Junction:
- -65°C ~ 125°C
SB140-B FAQ
1.How can I place an order for SB140-B through Aetrix?
Please submit a Request for Quotation (RFQ) for SB140-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 SB140-B reliable?
The price and inventory of SB140-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SB140-B is usually 5 days.
3.What payment methods are accepted for SB140-B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SB140-B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SB140-B?
SB140-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SB140-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 SB140-B?
For technical support, including SB140-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SB140-B requirements.
6.How does Aetrix verify that SB140-B is sourced from the original manufacturer or authorized distributors?
All SB140-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 SB140-B meets industry standards.
7.What is the process for return or replacement of SB140-B?
All SB140-B units undergo pre-shipment inspection (PSI). If there is an issue with SB140-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 SB140-B part is unused and in its original packaging.
Return procedure for SB140-B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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