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onsemi SZ1SMB5940BT3G
- Part No.:
- SZ1SMB5940BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5940BT3G.pdf
- Description:
- DIODE ZENER 43V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,440
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Product details
Overview
SZ1SMB5940BT3G from onsemi is a 3 W surface-mount Zener diode with nominal zener voltage of 43 V, ±5% tolerance, 8.7 Ω dynamic impedance at 53 mA test current, and 0.25 μA leakage current at 32.7 V reverse voltage. It serves as a precision voltage reference or overvoltage clamp in DC power regulation circuits for automotive and industrial control modules.
For engineers reviewing the SZ1SMB5940BT3G 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 zener voltage temperature coefficient above 40 V.
Technical Context
This device operates as a two-terminal, unidirectional voltage regulator in reverse-bias mode, with zener breakdown triggered at 40.85–45.15 V under 53 mA test current. Its flat handling surface and modified L-bend leads support accurate placement and robust solder joint reliability on FR-4 PCBs.
The SMB (Case 403A) package enables top-side or bottom-side mounting, and its void-free plastic molding meets UL 94 V-0 flammability rating. Thermal derating begins at 25°C ambient (550 mW) and 75°C lead temperature (3.0 W), with junction-to-lead resistance of 40 °C/W.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 40.85–45.15 V @ IZT = 53 mA - defines regulated output range for stable reference or clamping |
| Zener Impedance (ZZT) | 8.7 Ω @ IZT = 53 mA - low dynamic resistance ensures minimal voltage deviation under load variation |
| Max Power Dissipation | 3.0 W @ TL = 75°C - supports high-energy transient suppression without heatsink in compact layouts |
| Leakage Current (IR) | 0.25 μA @ VR = 32.7 V - ultra-low off-state current preserves efficiency in battery-backed systems |
| ESD Rating | Class 3 (>16 kV HBM) - withstands electrostatic discharge during automated assembly and field operation |
| Operating Temp Range | −65 °C to +150 °C - qualified for under-hood automotive and industrial environments |
| AEC−Q101 Qualified | Yes - validated for automotive electronics per stress-test requirements including HTOL and TC |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with cathode polarity band; dimensions: 3.56 mm × 4.32 mm × 1.02 mm (L × W × H); Pb-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference node | Connected to lower-potential side of regulated circuit; establishes reference ground path for voltage clamping |
| Cathode | Zener breakdown terminal / Regulation output node | Connected to higher-potential rail; delivers stable 43 V reference or absorbs overvoltage transients |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and high-temperature operating life |
| Flat handling surface | Enables consistent pick-and-place accuracy and coplanarity on fine-pitch PCBs without tombstoning |
| Modified L-bend leads | Increases solder contact area by >30% vs. standard gull-wing, improving mechanical strength and thermal transfer |
| UL 94 V-0 flammability | Self-extinguishing plastic housing prevents flame propagation in safety-critical power subsystems |
| Polarity band marking | Visible cathode indicator ensures correct orientation during manual rework and AOI inspection |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC Input Protection |
|---|---|
|
Use Scenario: Clamping 48 V supply rail transients induced by solenoid switching in diesel engine management systems. IC Role / Device Role / Timing Role: Two-terminal passive voltage clamp protecting microcontroller I/O and sensor interface ICs from ISO 7637-2 pulse 1/2b surges. Use Value: Withstands 3 W peak surge without degradation, maintaining <0.25 μA leakage to avoid loading 12-bit ADC reference dividers. |
Use Scenario: Stabilizing 42 V auxiliary supply in modular programmable logic controller backplanes. IC Role / Device Role / Timing Role: Precision shunt reference providing 43 V setpoint for isolated DC-DC feedback loops and brownout detection comparators. Use Value: 8.7 Ω ZZT ensures <±0.1 V regulation error across −40 °C to +125 °C ambient, meeting SIL-2 functional safety margin. |
| Telecom Power Supply Monitoring | Medical Diagnostic Equipment Biasing |
|
Use Scenario: Overvoltage protection for 48 V telecom rectifier outputs feeding distributed power architecture boards. IC Role / Device Role / Timing Role: Standby-mode zener clamp absorbing lightning-induced surges while minimizing standby power loss. Use Value: 16 kV HBM ESD rating eliminates need for external TVS staging, reducing BOM count and board space by 25%. |
Use Scenario: Generating stable bias voltage for photomultiplier tube (PMT) anode chains in portable X-ray analyzers. IC Role / Device Role / Timing Role: Low-noise, low-drift voltage reference enabling sub-1% gain stability in high-sensitivity analog front-ends. Use Value: −65 °C to +150 °C operating range supports sterilization cycles and cold-chain transport without parameter shift. |
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-C43LT1G | 250 mW SOT-23 package; 41.5–44.5 V range; ZZT = 90 Ω @ 5 mA | Lower power rating limits use to signal-level clamping only; unsuitable for 3 W surge absorption | Select when space-constrained PCBs require SOT-23 footprint and peak power <0.5 W |
| SZ1SMB5940B-T | Same electrical specs but non-Pb-free; obsolete packaging (bulk vs. tape/reel); no AEC-Q101 documentation | Lacks automotive qualification evidence and modern traceability; not accepted for new automotive designs | Select only for legacy repair where RoHS compliance is waived and PPAP is not required |
Compared with BZX84-C43LT1G and SZ1SMB5940B-T, the SZ1SMB5940BT3G uniquely combines 3 W power handling, AEC−Q101 validation, and Pb-free compliance-making it the sole choice for production automotive and industrial systems requiring long-term supply assurance and regulatory alignment.
Availability
SZ1SMB5940BT3G is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, telecom power supplies, and medical diagnostic equipment requiring stable component supply with full traceability and lifecycle continuity.
Supply support for SZ1SMB5940BT3G 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 (Semiconductor Components Industries, LLC) 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 voltage regulation in harsh-environment electronics, emphasizing AEC−Q101 compliance, robust thermal performance, and manufacturability in high-volume SMT lines.
FAQ
What is the zener voltage tolerance for SZ1SMB5940BT3G?
The SZ1SMB5940BT3G has a nominal zener voltage of 43 V with a tolerance of ±5%, resulting in a guaranteed range of 40.85 V to 45.15 V at 53 mA test current (IZT). 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 SZ1SMB5940BT3G suitable for automotive applications?
Yes, SZ1SMB5940BT3G is explicitly AEC−Q101 qualified and PPAP capable, as stated in the Features section of the datasheet. The "SZ" prefix denotes automotive-grade manufacturing controls, site-specific change management, and full qualification testing-including temperature cycling, high-temperature operating life, and ESD robustness-making it approved for use in engine control, body electronics, and ADAS subsystems.
What is the maximum steady-state power dissipation for SZ1SMB5940BT3G at 25°C ambient?
The maximum steady-state power dissipation for SZ1SMB5940BT3G is 550 mW at TA = 25°C, with linear derating of 4.4 mW/°C above that temperature. This value is specified in the Maximum Ratings table (page 1) and assumes use on an FR-4 board with the recommended footprint per the datasheet's Soldering Footprint section.
Does SZ1SMB5940BT3G have a documented ESD rating?
Yes, SZ1SMB5940BT3G has an ESD rating of Class 3 (>16 kV) per the Human Body Model (HBM), as published in the Features section of the onsemi datasheet. This rating reflects tested performance and supports robust handling during SMT assembly and field service without additional ESD protection circuitry.
What is the thermal resistance from junction-to-ambient (RJA) for SZ1SMB5940BT3G?
The thermal resistance from junction-to-ambient (RJA) for SZ1SMB5940BT3G is 226 °C/W, measured on an FR-4 board using the recommended footprint. This value appears in the Maximum Ratings table on page 1 of the datasheet and is critical for calculating junction temperature rise under continuous DC power conditions.
SZ1SMB5940BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 43 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 53 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 32.7 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
SZ1SMB5940BT3G FAQ
1.How can I place an order for SZ1SMB5940BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5940BT3G 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 SZ1SMB5940BT3G reliable?
The price and inventory of SZ1SMB5940BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5940BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5940BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5940BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5940BT3G?
SZ1SMB5940BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5940BT3G 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 SZ1SMB5940BT3G?
For technical support, including SZ1SMB5940BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5940BT3G requirements.
6.How does Aetrix verify that SZ1SMB5940BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5940BT3G 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 SZ1SMB5940BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5940BT3G?
All SZ1SMB5940BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5940BT3G, 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 SZ1SMB5940BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5940BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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