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onsemi 1SMB5931BT3
- Part No.:
- 1SMB5931BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5931BT3.pdf
- Description:
- DIODE ZENER 18V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:4,470
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Product details
Overview
1SMB5931BT3 from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 18 V (±5%), maximum Zener impedance of 20.8 Ω at 12 mA test current, and reverse leakage current ≤0.25 μA at 14.4 V. It operates across −65 °C to +150 °C and is qualified to AEC−Q101 for automotive power rail clamping and voltage reference applications.
For engineers reviewing the 1SMB5931BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 18 V regulation tolerance, 650 mA maximum DC Zener current, thermal resistance of 226 °C/W at TA = 25 °C, and SMB (Case 403A) package compatibility with automated SMT assembly.
Technical Context
This device functions as a precision DC voltage regulator and transient suppressor in low-power analog and power supply circuits. Its 18 V nominal Zener voltage is specified at IZT = 12 mA with ±5% tolerance, and it maintains stable regulation under steady-state dissipation up to 550 mW at 25 °C ambient - derating linearly above that temperature.
The 1SMB5931BT3 features a cathode-band polarity indicator, modified L-bend leads for enhanced pad bonding, and UL 94 V−0 flammability rating. Its ESD rating exceeds 16 kV per Human Body Model, supporting robust handling in automotive and industrial manufacturing environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V nominal (17.1–18.9 V range), ±5% tolerance - ensures predictable clamping level in 12–24 V system rails. |
| Zener Test Current (IZT) | 12 mA - defines operating point where VZ and dynamic impedance are guaranteed per spec. |
| Zener Impedance (ZZT) | 20.8 Ω max at IZT - limits regulation error under load variation in feedback or reference paths. |
| Max DC Zener Current (IZM) | 83 mA - sets absolute upper limit for continuous current without exceeding 3 W junction power limit. |
| Reverse Leakage (IR) | ≤0.25 μA at VR = 14.4 V - ensures minimal quiescent current draw in high-impedance bias networks. |
| Thermal Resistance (RJA) | 226 °C/W at TA = 25 °C - determines junction temperature rise under real PCB thermal conditions. |
| Package | SMB (Case 403A), surface-mount - supports high-density layout and reflow-compatible assembly with standard footprint. |
Pinout & Package
SMB (Case 403A) plastic surface-mount package with cathode indicated by band; dimensions: 3.56 mm × 4.32 mm × 2.20 mm (L × W × H); modified L-bend leads for reliable solder joint formation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node | Connected to circuit common or lower-potential rail; forms cathode-to-anode reverse-bias path for regulation. |
| Cathode | Regulated output node | Provides stable 18 V relative to anode when reverse-biased above VZ; marked with polarity band. |
Key Features
| Feature | Design Value |
|---|---|
| 3 W Power Rating at TL = 75 °C | Enables use in higher-power voltage clamp roles without heatsinking on thermally adequate PCBs. |
| AEC−Q101 Qualified | Validated for automotive electronics including body control modules and sensor interfaces requiring reliability certification. |
| ESD Rating >16 kV (HBM) | Reduces risk of field failure during handling and assembly in uncontrolled ESD environments. |
| Pb−Free (RoHS Compliant) | Meets global environmental compliance requirements without sacrificing solderability or thermal performance. |
| UL 94 V−0 Flammability | Ensures flame-retardant behavior under fault conditions, supporting safety-critical board-level compliance. |
Applications
| Automotive Sensor Reference | Industrial PLC Input Protection |
|---|---|
Use Scenario: Provides stable 18 V reference for analog front-end circuits in engine coolant temperature sensors. IC Role / Device Role / Timing Role: Zener diode acting as shunt voltage reference and overvoltage clamp. Use Value: Maintains ADC accuracy despite battery transients up to ±100 V due to low ZZT and AEC−Q101 qualification. |
Use Scenario: Clamps 24 V DC input lines against surge events in programmable logic controller digital inputs. IC Role / Device Role / Timing Role: Transient voltage suppressor protecting optocoupler input stages. Use Value: Limits peak voltage to ≤20 V with <0.25 μA leakage, preserving signal integrity and long-term reliability. |
| Medical Instrument Power Rail Clamp | Telecom Line Card Bias Supply |
Use Scenario: Stabilizes 18 V bias rail for op-amp-based signal conditioning in portable ultrasound front-ends. IC Role / Device Role / Timing Role: Precision shunt regulator maintaining reference stability across temperature. Use Value: Delivers ±5% VZ tolerance and <21 Ω impedance to minimize gain drift in critical analog paths. |
Use Scenario: Sets regulated bias point for line driver ICs in DSLAM interface cards operating from 24 V backplane. IC Role / Device Role / Timing Role: Voltage reference and noise filter in low-noise analog bias network. Use Value: Achieves <0.25 μA leakage and 226 °C/W RJA, enabling compact layout without thermal derating penalties. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C18LT1G | 250 mW SOT-23 package; 18 V ±5%; ZZT = 45 Ω @ 5 mA | Lower power rating and higher impedance limit use to low-current references only | Select when board space is constrained and power dissipation remains below 250 mW |
| SMBJ18A | TVS diode, 18 V standoff, 200 W peak pulse power, bidirectional | Designed for transient suppression, not precision regulation; no guaranteed DC Zener curve | Choose for surge protection where precise DC regulation is secondary to clamping energy handling |
Compared with BZX84-C18LT1G and SMBJ18A, the 1SMB5931BT3 uniquely balances 3 W steady-state power, low 20.8 Ω ZZT, and AEC−Q101 qualification - making it optimal for automotive and industrial voltage reference roles demanding both accuracy and ruggedness.
Availability
1SMB5931BT3 is available at Aetrix Electronics and suitable for automotive sensor modules, industrial PLC input stages, medical instrument bias supplies, and telecom line card designs requiring stable component supply and full traceability.
Supply support for 1SMB5931BT3 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The 1SMB5931BT3 belongs to the 1SMB59xxBT3 series of 3 W Zener regulators designed specifically for high-reliability voltage reference and clamping in automotive and industrial power systems.
FAQ
What is the Zener voltage tolerance of the 1SMB5931BT3?
The 1SMB5931BT3 has a Zener voltage tolerance of ±5%, with a nominal value of 18 V and a guaranteed range of 17.1 V to 18.9 V at IZT = 12 mA and TL = 30 °C. This tolerance is explicitly defined in the Electrical Characteristics table on page 3 of the official datasheet and applies to all units in the SZ/1SMB5931BT3, G ordering variant.
Is the 1SMB5931BT3 suitable for automotive applications?
Yes, the 1SMB5931BT3 is AEC−Q101 qualified and PPAP capable, as confirmed in the Features section of the datasheet. Its construction, testing, and documentation meet automotive-grade reliability requirements, making it appropriate for use in engine control units, body electronics, and ADAS sensor interfaces where certified component qualification is mandatory.
What is the maximum power dissipation of the 1SMB5931BT3 at room temperature?
The 1SMB5931BT3 delivers 550 mW maximum steady-state power dissipation at TA = 25 °C, with linear derating above that temperature at 4.4 mW/°C. This value is specified in the Maximum Ratings table and reflects operation on a FR-4 board using the recommended footprint - not the 3 W rating, which applies only at TL = 75 °C with zero lead length.
Does the 1SMB5931BT3 have Pb−Free packaging?
Yes, the "G" suffix in 1SMB5931BT3 indicates Pb−Free (RoHS-compliant) packaging, as stated in the Ordering Information and Device Marking sections. The datasheet confirms Pb−Free availability for this part number and specifies compatibility with standard reflow soldering profiles, including peak temperatures up to 260 °C for 10 seconds.
What is the Zener impedance of the 1SMB5931BT3 and why does it matter?
The 1SMB5931BT3 has a maximum Zener impedance (ZZT) of 20.8 Ω at IZT = 12 mA. This low dynamic impedance ensures minimal voltage deviation under varying load currents - critical for maintaining accuracy in voltage reference and feedback circuits where regulation stability directly impacts system performance.
1SMB5931BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 12 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB5931BT3 FAQ
1.How can I place an order for 1SMB5931BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5931BT3 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 1SMB5931BT3 reliable?
The price and inventory of 1SMB5931BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5931BT3 is usually 5 days.
3.What payment methods are accepted for 1SMB5931BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5931BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5931BT3?
1SMB5931BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5931BT3 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 1SMB5931BT3?
For technical support, including 1SMB5931BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5931BT3 requirements.
6.How does Aetrix verify that 1SMB5931BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB5931BT3 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 1SMB5931BT3 meets industry standards.
7.What is the process for return or replacement of 1SMB5931BT3?
All 1SMB5931BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5931BT3, 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 1SMB5931BT3 part is unused and in its original packaging.
Return procedure for 1SMB5931BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB5931BT3 Tags
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