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onsemi SZ1SMB5938BT3G
- Part No.:
- SZ1SMB5938BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5938BT3G.pdf
- Description:
- DIODE ZENER 36V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,807
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Product details
Overview
SZ1SMB5938BT3G from onsemi is a 3 W surface-mount Zener diode designed for precision voltage regulation and overvoltage protection in DC power rails. It delivers a nominal Zener voltage of 36 V (±5%), with a maximum Zener impedance of 10.4 Ω at 38 mA test current, 27.4 V reverse breakdown threshold, and 41 A maximum DC Zener current - deployed in automotive power supply clamping and industrial sensor biasing circuits.
For engineers reviewing the SZ1SMB5938BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include its AEC−Q101 qualification, 16 kV HBM ESD rating, SMB package thermal performance (RJA = 226 °C/W), and stable 36 V regulation under 75°C lead temperature conditions.
Technical Context
This device operates as a two-terminal, polarity-sensitive voltage reference diode with cathode-indicated marking. Its Zener action provides stable reverse-biased conduction above 34.2 V, maintaining regulation across 38 mA test current while exhibiting low dynamic impedance (10.4 Ω) and tight ±5% voltage tolerance.
Thermal derating begins at 75°C lead temperature (3.0 W max), with junction-to-ambient resistance fixed at 226 °C/W on FR-4 board. The SMB package supports top- or bottom-side PCB mounting and complies with UL 94 V-0 flammability standard and Pb-free soldering requirements (260°C/10 s).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 36 V nominal (34.2–37.8 V range); enables precise 36 V rail clamping in automotive ECUs and industrial PLC I/O modules. |
| Power Dissipation (PD) | 3.0 W @ TL = 75°C; supports sustained surge handling without thermal runaway in compact SMT layouts. |
| Zener Impedance (ZZT) | 10.4 Ω @ IZT = 38 mA; ensures minimal output voltage deviation during load transients in feedback loops. |
| Reverse Leakage (IR) | 0.25 μA @ VR = 27.4 V; guarantees negligible standby current in battery-backed systems. |
| Max DC Zener Current (IZM) | 41 A; defines absolute safe operating limit for transient overvoltage suppression events. |
| ESD Rating | Class 3 (>16 kV HBM); meets stringent electrostatic robustness requirements for automotive assembly environments. |
| Operating Temperature | −65°C to +150°C; validated for under-hood and industrial control cabinet deployments. |
Pinout & Package
The SZ1SMB5938BT3G uses the SMB (Case 403A) surface-mount plastic package with modified L-bend leads, flat handling surface, and cathode polarity band. Package dimensions: 3.56 mm × 4.32 mm × 1.02 mm (L × W × H), UL 94 V-0 rated, void-free molded construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Low-side reference node | Connected to ground or lower-potential rail; establishes reference point for Zener regulation. |
| Cathode | Reverse-biased Zener terminal / High-side regulated output | Connected to protected voltage rail; conducts when input exceeds 34.2 V to clamp and stabilize. |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 Qualified | Validated for automotive powertrain and body electronics per stress-test protocol, enabling direct use in Tier-1 ECU designs. |
| 16 kV HBM ESD Robustness | Eliminates need for external ESD protection in CAN/LIN bus interface power domains and sensor front-ends. |
| Flat Handling Surface | Ensures consistent pick-and-place accuracy during high-speed SMT assembly, reducing placement skew and tombstoning risk. |
| Pb-Free & RoHS Compliant | Meets global environmental compliance mandates without sacrificing thermal or electrical performance. |
| Top/Bottom Mount Flexibility | Enables layout optimization in space-constrained modules where component height or board-side access dictates orientation. |
Applications
| Automotive Engine Control Unit (ECU) Power Clamp | Industrial 24 V Sensor Bias Supply |
|---|---|
|
Use Scenario: Clamps 12 V/24 V battery rail surges during load dump events in engine management systems. IC Role / Device Role / Timing Role: Two-terminal passive voltage clamp protecting microcontroller I/O and analog front-end circuitry. Use Value: Withstands 41 A peak current and maintains 36 V regulation to prevent latch-up or damage during ISO 7637-2 Pulse 5a transients. |
Use Scenario: Provides stable bias voltage for pressure and temperature sensors in factory automation PLCs. IC Role / Device Role / Timing Role: Precision Zener reference establishing fixed 36 V reference for ratiometric ADC excitation. Use Value: ±5% tolerance and 10.4 Ω dynamic impedance ensure <0.5% measurement error drift across −40°C to +125°C ambient. |
| Telecom DC-DC Converter Overvoltage Protection | Medical Diagnostic Equipment Power Rail Stabilizer |
|
Use Scenario: Guards isolated 36 V secondary-side outputs in telecom AC/DC adapters against fault-induced overvoltage. IC Role / Device Role / Timing Role: Standby-mode shunt regulator that activates only during overvoltage faults. Use Value: 0.25 μA leakage at 27.4 V minimizes quiescent loss, extending hold-up time in backup power stages. |
Use Scenario: Stabilizes auxiliary 36 V supply feeding analog signal conditioning circuits in ultrasound imaging front-ends. IC Role / Device Role / Timing Role: Low-noise voltage reference source for precision op-amp biasing and DAC reference buffers. Use Value: AEC−Q101 qualification and −65°C to +150°C operation support reliability-critical medical certifications (IEC 60601-1). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMB5938BT3G | Same electrical specs and SMB package, but lacks AEC−Q101 qualification and SZ-prefix automotive traceability. | Approved for commercial/industrial use only; not suitable for automotive PPAP-controlled production. | Select when cost sensitivity outweighs automotive compliance requirements and full lifecycle traceability is not mandated. |
| BZX84-C36LT1G | Lower power (350 mW), SOT-23 package, 36 V ±5%, higher ZZT (90 Ω), no AEC−Q101 rating. | Limited to low-current biasing and signal-level clamping; unsuitable for 3 W surge handling or automotive under-hood use. | Choose only for space-constrained, low-power applications where thermal dissipation <0.5 W is sufficient. |
Compared with 1SMB5938BT3G and BZX84-C36LT1G, the SZ1SMB5938BT3G uniquely combines automotive-grade qualification, 3 W power capability, and low 10.4 Ω impedance - making it the sole option for AEC-compliant 36 V clamping in high-reliability power systems.
Availability
SZ1SMB5938BT3G is available at Aetrix Electronics and suitable for automotive ECU design, industrial sensor biasing, telecom power protection, and medical diagnostic equipment requiring stable component supply and long-term manufacturing continuity.
Supply support for SZ1SMB5938BT3G 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 engineered specifically for high-reliability DC voltage regulation and transient suppression - targeting automotive power systems and industrial controls demanding AEC−Q101 validation and robust thermal performance.
FAQ
What is the Zener voltage tolerance for SZ1SMB5938BT3G?
The SZ1SMB5938BT3G has a nominal Zener voltage of 36 V with a tolerance of ±5%, meaning its actual reverse breakdown voltage falls between 34.2 V and 37.8 V at the specified test current of 38 mA. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet and applies across the full operating temperature range.
Is SZ1SMB5938BT3G qualified for automotive applications?
Yes, SZ1SMB5938BT3G is explicitly AEC−Q101 qualified and PPAP capable, as stated in the Features section of the onsemi datasheet. The "SZ" prefix denotes automotive-grade traceability, site control, and enhanced reliability testing - distinguishing it from the commercial-grade 1SMB5938BT3G variant.
What is the maximum power dissipation of SZ1SMB5938BT3G at 100°C ambient?
At 100°C ambient temperature, the SZ1SMB5938BT3G must be derated from its 550 mW rating at 25°C using the 4.4 mW/°C derating factor. This yields a maximum power dissipation of approximately 220 mW (550 mW − 4.4 mW/°C × 75°C). However, its primary thermal rating is defined at 75°C lead temperature (3.0 W), which remains the governing limit for PCB-mounted operation.
Does SZ1SMB5938BT3G have a specified junction-to-ambient thermal resistance?
Yes, the SZ1SMB5938BT3G has a specified RJA of 226 °C/W when mounted on an FR-4 board using the recommended footprint. This value appears in the Maximum Ratings table and determines allowable power dissipation under natural convection conditions - critical for thermal design in enclosed industrial enclosures.
What is the reverse leakage current specification for SZ1SMB5938BT3G?
The reverse leakage current (IR) for SZ1SMB5938BT3G is specified as 0.25 μA maximum at a reverse voltage (VR) of 27.4 V, per the Electrical Characteristics table. This ultra-low leakage supports energy-sensitive applications such as battery-powered instrumentation where standby current must remain below 1 μA.
SZ1SMB5938BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 36 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 38 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 27.4 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SZ1SMB5938BT3G FAQ
1.How can I place an order for SZ1SMB5938BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5938BT3G 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 SZ1SMB5938BT3G reliable?
The price and inventory of SZ1SMB5938BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5938BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5938BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5938BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5938BT3G?
SZ1SMB5938BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5938BT3G 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 SZ1SMB5938BT3G?
For technical support, including SZ1SMB5938BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5938BT3G requirements.
6.How does Aetrix verify that SZ1SMB5938BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5938BT3G 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 SZ1SMB5938BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5938BT3G?
All SZ1SMB5938BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5938BT3G, 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 SZ1SMB5938BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5938BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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