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onsemi 1SMA5931BT3
- Part No.:
- 1SMA5931BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA5931BT3.pdf
- Description:
- DIODE ZENER 18V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,571
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Product details
Overview
1SMA5931BT3 from onsemi is a 1.5 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 13.7 V. It operates from −65 °C to +150 °C and is AEC-Q101 qualified for automotive applications requiring stable voltage regulation in power supply rails and overvoltage protection circuits.
For engineers reviewing the 1SMA5931BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its 18 V regulation tolerance, low-profile SMA package (Case 403D), thermal resistance of 250 °C/W (junction-to-ambient), ESD rating >16 kV (HBM), and Pb-free compliance per J-STD-609.
Technical Context
This device functions as a precision voltage reference and shunt regulator in DC power conditioning circuits. Its zener breakdown is specified at IZT = 12 mA with VZ = 17.1–18.9 V, and it maintains low dynamic impedance (ZZT = 20.8 Ω) and tight regulation under varying load conditions.
The 1SMA5931BT3 features a cathode-indicated polarity band, UL 94 V-0 flammability rating, and is rated for 260 °C soldering (10 s). Its thermal derating begins at TA = 25 °C (0.5 W max) and TL = 75 °C (1.5 W max), supporting reliable operation in compact, thermally constrained PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1–18.9 V @ IZT = 12 mA - defines regulated output voltage range under standard test conditions |
| Power Dissipation (PD) | 0.5 W @ TA = 25 °C - maximum continuous power in still air without heatsinking |
| Zener Impedance (ZZT) | 20.8 Ω @ IZT = 12 mA - low dynamic resistance ensures stable regulation under load transients |
| Reverse Leakage (IR) | ≤0.25 μA @ VR = 13.7 V - minimal standby current preserves efficiency in low-power systems |
| Thermal Resistance (RJA) | 250 °C/W - determines junction temperature rise above ambient at given power dissipation |
| ESD Rating (HBM) | >16 kV - enables robust handling and assembly in uncontrolled environments |
| Operating Temperature | −65 °C to +150 °C - supports deployment in under-hood automotive and industrial control modules |
Pinout & Package
1SMA5931BT3 uses the SMA (DO-214AC) surface-mount package (Case 403D), measuring 4.06–4.57 mm in length (E), 2.29–2.92 mm in width (D), and 1.97–2.20 mm in height (A). Polarity is marked by a cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Zener anode connection point in reverse-bias configuration | Connected to higher-potential rail; regulates voltage by sinking current when input exceeds VZ |
| Anode | Zener cathode connection point in reverse-bias configuration | Typically tied to system ground or return path; completes shunt regulation loop |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock testing |
| Pb-free (RoHS-compliant) construction | Meets J-STD-609 Class 3 moisture sensitivity level (MSL 1) and eliminates lead contamination risk in assembly |
| Low-profile SMA package | Enables high-density placement on double-sided PCBs and compatibility with automated pick-and-place equipment |
| Flat handling surface | Ensures consistent coplanarity during reflow soldering and reduces tombstoning risk in fine-pitch layouts |
| UL 94 V-0 flammability rating | Confirms self-extinguishing behavior under flame exposure-critical for safety-critical power supplies |
Applications
| Automotive Power Supply Regulation | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Regulating 12 V battery-derived rails in engine control units (ECUs) and body control modules (BCMs). IC Role / Device Role / Timing Role: Shunt voltage reference that clamps transient overvoltages and stabilizes microcontroller supply voltage. Use Value: Maintains 18 V regulation tolerance across −40 °C to +125 °C ambient, enabling reliable MCU operation despite load dump spikes. |
Use Scenario: Providing stable reference voltage for analog front-end amplifiers in factory-floor pressure/temperature transmitters. IC Role / Device Role / Timing Role: Precision voltage clamp protecting ADC inputs from ESD-induced overvoltage events. Use Value: Leverages >16 kV HBM ESD rating and ≤0.25 μA leakage to preserve signal integrity in 4–20 mA loop-powered sensors. |
| Consumer Power Adapter Protection | Telecom DC-DC Converter Feedback |
Use Scenario: Overvoltage protection in USB-C PD adapter secondary-side feedback networks. IC Role / Device Role / Timing Role: Zener-based crowbar circuit triggering shutdown when output exceeds safe threshold. Use Value: Delivers fast response with 20.8 Ω ZZT and 1.5 W surge capability, preventing downstream IC damage during fault conditions. |
Use Scenario: Voltage reference in isolated flyback converter feedback paths for telecom base station power supplies. IC Role / Device Role / Timing Role: Stable 18 V reference setting optocoupler bias current to regulate primary-side PWM duty cycle. Use Value: Ensures ±5% VZ tolerance and low thermal drift (θVZ ~+0.075%/°C for 18 V devices) across full operating temperature range. |
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 | 300 mW SOT-23 package; VZ = 17.1–19.1 V; ZZT = 45 Ω @ 5 mA | Lower power rating limits use to <100 mA load currents; unsuitable for 1.5 W surge events | Select when board space is critical and peak power demands are <0.3 W |
| 1N4746A | 1 W through-hole DO-41; VZ = 17.1–18.9 V; ZZT = 17 Ω @ 12 mA; no AEC-Q101 qualification | Lacks automotive qualification and surface-mount compatibility; requires manual insertion or wave soldering | Select for cost-sensitive industrial prototypes where reflow compatibility is not required |
Compared with BZX84-C18LT1G and 1N4746A, the 1SMA5931BT3 delivers higher power handling (1.5 W), AEC-Q101 qualification, and superior thermal performance in SMT layouts-making it optimal for production automotive and high-reliability industrial designs.
Availability
1SMA5931BT3 is available at Aetrix Electronics and suitable for automotive power management, industrial sensor interfaces, consumer adapter protection, and telecom DC-DC converter feedback requiring stable component supply and long-term lifecycle support.
Supply support for 1SMA5931BT3 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 management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The 1SMA5931BT3 belongs to the 1SMA59xxBT3/SZ1SMA59xxBT3G family of 1.5 W Zener regulators designed specifically for high-reliability surface-mount voltage reference and overvoltage protection in automotive and industrial power systems.
FAQ
What is the exact zener voltage tolerance for 1SMA5931BT3?
The 1SMA5931BT3 has a nominal zener voltage of 18 V with a guaranteed tolerance of ±5%, meaning the actual VZ falls between 17.1 V and 18.9 V when measured at IZT = 12 mA and thermal equilibrium. This tolerance is explicitly defined in the Electrical Characteristics table on page 2 of the official datasheet (Rev. 7, November 2011).
Is 1SMA5931BT3 suitable for automotive applications?
Yes, the 1SMA5931BT3 is AEC-Q101 qualified and PPAP capable, as confirmed in the Features section of the datasheet. The "SZ" prefix variant (SZ1SMA5931BT3G) meets automotive site and control change requirements, and both variants share identical electrical and thermal specifications, making 1SMA5931BT3 appropriate for under-hood and chassis-mounted automotive modules.
What is the maximum steady-state power dissipation for 1SMA5931BT3 at 75°C lead temperature?
The 1SMA5931BT3 delivers 1.5 W DC power dissipation at TL = 75°C with zero lead length, as stated in the Maximum Ratings table. Above 75°C, it derates linearly at 20 mW/°C. This rating assumes a 1 in² copper pad on FR-4 board per Note 1 in the datasheet.
Does 1SMA5931BT3 have Pb-free packaging?
Yes, the "G" suffix in the ordering code (e.g., SZ1SMA5931BT3G) explicitly denotes Pb-free packaging compliant with J-STD-609. The base part number 1SMA5931BT3 is also available in Pb-free form, as confirmed in the Ordering Information table and Device Marking Information section of the datasheet.
What is the thermal resistance junction-to-ambient for 1SMA5931BT3?
The thermal resistance junction-to-ambient (RJA) for 1SMA5931BT3 is 250 °C/W, specified for operation at TA = 25°C on an FR-4 board using onsemi's minimum recommended footprint. This value is listed in the Maximum Ratings table and governs allowable power dissipation in natural convection environments.
1SMA5931BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 1SMA59xxBT3G
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 12 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA5931BT3 FAQ
1.How can I place an order for 1SMA5931BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA5931BT3 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 1SMA5931BT3 reliable?
The price and inventory of 1SMA5931BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA5931BT3 is usually 5 days.
3.What payment methods are accepted for 1SMA5931BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA5931BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA5931BT3?
1SMA5931BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA5931BT3 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 1SMA5931BT3?
For technical support, including 1SMA5931BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA5931BT3 requirements.
6.How does Aetrix verify that 1SMA5931BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA5931BT3 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 1SMA5931BT3 meets industry standards.
7.What is the process for return or replacement of 1SMA5931BT3?
All 1SMA5931BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA5931BT3, 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 1SMA5931BT3 part is unused and in its original packaging.
Return procedure for 1SMA5931BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA5931BT3 Tags
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