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onsemi SZ1SMB5942BT3G
- Part No.:
- SZ1SMB5942BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5942BT3G.pdf
- Description:
- DIODE ZENER 51V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:5,292
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Product details
Overview
SZ1SMB5942BT3G from onsemi is a 3 W surface-mount Zener diode with nominal zener voltage of 51 V, ±5% tolerance, 7.3 Ω dynamic impedance at 70 mA test current, and 0.25 μA reverse leakage at 38.8 V. It regulates voltage in power supply rails and overvoltage protection circuits for automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SZ1SMB5942BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy, thermal derating above 75°C, SMB package footprint compatibility, and AEC−Q101 qualification for automotive use.
Technical Context
This device operates as a precision shunt regulator with stable breakdown behavior under DC and transient conditions. Its 51 V nominal zener voltage targets mid-range overvoltage clamping in 48 V automotive systems and industrial 24/48 V DC distribution networks.
Thermal performance is defined by 40 mW/°C derating above 75°C junction temperature and 226 °C/W junction-to-ambient thermal resistance on FR-4 board. The SMB package supports top-side or bottom-side PCB mounting with modified L-bend leads for enhanced solder joint reliability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 48.45 V (min) to 53.55 V (max) at IZT = 70 mA - ensures ±5% regulation window for 48 V system reference |
| Zener Impedance (ZZT) | 7.3 Ω at IZT = 70 mA - low dynamic impedance maintains tight voltage regulation under load transients |
| Power Dissipation (PD) | 3.0 W @ TL = 75°C - supports continuous operation in thermally constrained automotive modules |
| Reverse Leakage (IR) | 0.25 μA @ VR = 38.8 V - minimal standby current preserves battery life in always-on vehicle subsystems |
| Thermal Resistance (RJA) | 226 °C/W - defines maximum ambient temperature rise for safe 550 mW operation at TA = 25°C |
| ESD Rating | Class 3 (>16 kV HBM) - withstands electrostatic discharge during automated PCB assembly and field handling |
| AEC−Q101 Qualified | Yes - validated for automotive applications including engine control, body electronics, and ADAS sensors |
Pinout & Package
The SZ1SMB5942BT3G uses the SMB (Case 403A) plastic surface-mount package with cathode indicated by a polarity band. Dimensions: 3.56 mm × 4.32 mm × 1.02 mm (L × W × H), lead pitch 2.03 mm, flat handling surface for accurate pick-and-place placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink terminal during forward bias | Connected to lower-potential node (e.g., ground or return rail) in shunt regulation configuration |
| Cathode | Zener breakdown terminal | Connected to regulated voltage node; polarity band identifies this terminal for correct PCB orientation |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables precise 48 V rail clamping without post-production trimming in automotive power modules |
| AEC−Q101 qualification | Validates reliability for under-hood applications with operating temperature range −65°C to +150°C |
| 16 kV HBM ESD rating | Eliminates need for external ESD protection in infotainment and gateway module input stages |
| Modified L-bend leads | Increases solder contact area for mechanical robustness in vibration-prone automotive environments |
| Pb-free (RoHS-compliant) | Meets global environmental compliance requirements for OEM production without process requalification |
Applications
| Automotive Engine Control Unit (ECU) | Industrial 48 V DC Power Distribution |
|---|---|
Use Scenario: Clamps transient spikes on 48 V sensor supply lines during load dump events. IC Role / Device Role / Timing Role: Shunt voltage regulator providing overvoltage protection for microcontroller analog inputs and CAN transceivers. Use Value: Maintains 51 V clamping threshold within ±5% across −40°C to +125°C, preventing damage to downstream 5 V LDOs and ADCs. |
Use Scenario: Stabilizes reference voltage for isolated DC-DC feedback loops in telecom rectifiers. IC Role / Device Role / Timing Role: Precision zener reference establishing stable 51 V setpoint for optocoupler-based error amplification. Use Value: 7.3 Ω dynamic impedance ensures <100 mV output deviation under 100 mA step load changes at 48 V input. |
| Medical Imaging Power Supply | Renewable Energy Battery Management |
Use Scenario: Provides voltage reference for high-voltage X-ray generator bias control. IC Role / Device Role / Timing Role: Stable zener source feeding DAC-controlled amplifier in HV feedback path. Use Value: 0.25 μA leakage at 38.8 V minimizes current error in 16-bit DAC reference chains, preserving measurement linearity. |
Use Scenario: Protects BMS MCU inputs from cell string overvoltage during fast charging of 13S Li-ion packs (~48 V nominal). IC Role / Device Role / Timing Role: Transient voltage suppressor clamping fault conditions before protection IC triggers shutdown. Use Value: 3 W steady-state dissipation handles 100 ms surge events per IEC 61000-4-5 Level 3 without degradation. |
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-C51LT1G | 250 mW SOT-23 package; 51 V ±5%; 70 Ω ZZT at 5 mA | Lower power rating limits use to signal-level protection only; unsuitable for 48 V rail clamping | Select when space-constrained PCBs require SOT-23 footprint and peak power < 0.25 W |
| SZ1SMB5941BT3G | 47 V nominal zener voltage; 8 Ω ZZT at 67 mA; same SMB package and AEC−Q101 qualification | Targets 42–48 V systems requiring tighter margin below 51 V threshold | Choose for legacy 42 V architectures or where 47 V clamping improves safety margin against 51 V overvoltage |
Compared with BZX84-C51LT1G and SZ1SMB5941BT3G, the SZ1SMB5942BT3G delivers higher power handling (3 W vs. 0.25 W) and lower dynamic impedance (7.3 Ω vs. 70 Ω or 8 Ω) for robust 48 V rail regulation, while maintaining identical AEC−Q101 qualification and SMB footprint compatibility.
Availability
SZ1SMB5942BT3G is available at Aetrix Electronics and suitable for automotive engine control units, industrial 48 V power distribution systems, and medical imaging power supplies requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SZ1SMB5942BT3G 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The 1SMB59xxBT3G/SZ1SMB59xxT3G series was designed specifically for high-reliability voltage regulation and transient suppression in automotive and industrial environments, emphasizing AEC−Q101 qualification, high ESD immunity, and stable thermal performance.
FAQ
What is the zener voltage tolerance of SZ1SMB5942BT3G?
The SZ1SMB5942BT3G has a zener voltage tolerance of ±5%, with a specified range of 48.45 V (minimum) to 53.55 V (maximum) at 70 mA test current. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the onsemi datasheet and applies directly to the SZ1SMB5942BT3G part number. The ±5% tolerance ensures predictable clamping behavior in 48 V automotive and industrial power systems where precise overvoltage thresholds are required.
Is SZ1SMB5942BT3G qualified for automotive applications?
Yes, SZ1SMB5942BT3G is AEC−Q101 qualified and PPAP capable, as explicitly stated in the Features section of the onsemi datasheet. The "SZ" prefix denotes automotive-grade qualification, and the device is rated for operation from −65°C to +150°C. This makes SZ1SMB5942BT3G suitable for under-hood engine control units, body control modules, and ADAS sensor power conditioning where automotive reliability standards apply.
What is the maximum power dissipation of SZ1SMB5942BT3G at 100°C ambient temperature?
At 100°C ambient temperature, SZ1SMB5942BT3G must be derated from its 550 mW rating at 25°C using the 4.4 mW/°C derating factor. This yields 550 mW − (4.4 mW/°C × 75°C) = 220 mW maximum allowable dissipation. This value is derived from the Maximum Ratings table on page 1 of the datasheet and reflects real-world thermal constraints when mounted on standard FR-4 PCBs without heatsinking.
Does SZ1SMB5942BT3G have a Pb-free construction?
Yes, SZ1SMB5942BT3G is Pb-free and RoHS-compliant, as confirmed by the "G" suffix in the part number and the "Pb−Free Package" designation in the Ordering Information table. The datasheet states "These are Pb−Free Devices*" and references the onsemi Soldering and Mounting Techniques Reference Manual for reflow profile guidance. This ensures compatibility with modern lead-free assembly processes used in automotive and industrial manufacturing.
What is the reverse leakage current specification for SZ1SMB5942BT3G?
The reverse leakage current for SZ1SMB5942BT3G is 0.25 μA maximum at a reverse voltage of 38.8 V, as specified in the Electrical Characteristics table on page 3. This parameter is measured at TL = 30°C and defines the diode's off-state current in shunt regulation applications. Low leakage preserves efficiency in battery-powered systems and prevents loading errors in precision reference circuits using SZ1SMB5942BT3G.
SZ1SMB5942BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 51 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 70 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 38.8 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SZ1SMB5942BT3G FAQ
1.How can I place an order for SZ1SMB5942BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5942BT3G 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 SZ1SMB5942BT3G reliable?
The price and inventory of SZ1SMB5942BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5942BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5942BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5942BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5942BT3G?
SZ1SMB5942BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5942BT3G 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 SZ1SMB5942BT3G?
For technical support, including SZ1SMB5942BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5942BT3G requirements.
6.How does Aetrix verify that SZ1SMB5942BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5942BT3G 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 SZ1SMB5942BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5942BT3G?
All SZ1SMB5942BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5942BT3G, 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 SZ1SMB5942BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5942BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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