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onsemi SZ1SMB5918BT3G
- Part No.:
- SZ1SMB5918BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5918BT3G.pdf
- Description:
- DIODE ZENER 5.1V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:22,902
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Product details
Overview
SZ1SMB5918BT3G from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 5.1 V, ±5% tolerance, 73.5 Ω dynamic impedance at 4 mA test current, and 2 mA maximum leakage current at 4 V reverse bias. It operates across −65 °C to +150 °C and is AEC−Q101 qualified for automotive power rail stabilization and overvoltage protection in DC-DC converter feedback loops.
For engineers reviewing the SZ1SMB5918BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include its 5.1 V regulation accuracy under 4 mA Zener test current, 294 mA maximum DC Zener current, SMB package thermal resistance (RJA = 226 °C/W), and Class 3 ESD rating (>16 kV HBM).
Technical Context
This device functions as a precision shunt voltage regulator in low-power, space-constrained applications where stable reference voltage is required despite input variation or load transients. Its 3 W steady-state power dissipation at TL = 75 °C and 550 mW at TA = 25 °C enable robust operation in thermally demanding environments without active cooling.
The SMB (Case 403A) package features a modified L-bend lead design for enhanced pad contact area and supports top-side or bottom-side PCB mounting. Polarity is indicated by a cathode band, and the device meets UL 94 V−0 flammability rating with Pb−Free construction compliant to RoHS and AEC−Q101 requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 4.84–5.36 V (±5% tolerance at IZT = 4 mA; ensures stable 5.1 V reference under typical bias conditions) |
| Zener Impedance (ZZT) | 73.5 Ω max at IZT = 4 mA (low dynamic impedance maintains regulation accuracy during small-signal load changes) |
| Max DC Zener Current (IZM) | 294 mA (supports up to 294 mA continuous shunt current without exceeding 3 W junction power limit) |
| Leakage Current (IR) | 2 µA max at VR = 4 V (minimal standby current preserves efficiency in battery-backed or low-quiescent circuits) |
| Thermal Resistance (RJA) | 226 °C/W (defines temperature rise per watt dissipated in standard FR-4 layout; requires thermal relief for >550 mW ambient operation) |
| ESD Rating | Class 3 (>16 kV HBM) (enables direct integration into unshielded automotive sensor interfaces without external ESD protection) |
| Operating Temperature | −65 °C to +150 °C (validated for under-hood automotive electronics and industrial control modules) |
Pinout & Package
SZ1SMB5918BT3G is housed in an SMB (Case 403A) surface-mount plastic package with cathode polarity indicated by a band on the body. The package measures 3.56 mm × 4.32 mm × 1.02 mm (L × W × H) and features modified L-bend leads for reliable solder joint formation on standard PCB footprints.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node | Connected to system ground or common return; establishes reference potential for Zener breakdown |
| Cathode | Regulated output node | Provides stable 5.1 V output when reverse-biased; connects to voltage rail or feedback node requiring clamping |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity testing, and mechanical shock per AEC standards |
| Class 3 ESD protection | Withstands >16 kV human-body-model discharge without parameter shift or failure-reduces need for external TVS devices |
| Pb−Free and RoHS compliant | Fully compatible with lead-free reflow profiles (260 °C/10 s max) and meets global environmental compliance mandates |
| Flat handling surface | Enables high-accuracy automated pick-and-place placement with <±0.1 mm positional tolerance on SMT lines |
| Top/bottom board mounting | Package symmetry allows flexible layout routing-no orientation constraints for double-sided PCB assembly |
Applications
| Automotive Body Control Module (BCM) | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Regulating 5 V supply rail for microcontroller peripherals in door module ECUs exposed to load dump and cold crank conditions. IC Role / Device Role / Timing Role: Shunt voltage regulator maintaining stable 5.1 V reference for ADC reference and CAN transceiver biasing. Use Value: ±5% VZ tolerance and −65 °C to +150 °C operation ensure functional safety compliance under extreme vehicle thermal cycles. |
Use Scenario: Clamping analog sensor output (e.g., 4–20 mA loop transmitter) to prevent overvoltage damage to downstream op-amps. IC Role / Device Role / Timing Role: Precision Zener clamp limiting signal swing to 5.1 V while drawing only 2 µA leakage at 4 V. Use Value: 73.5 Ω ZZT minimizes voltage deviation during transient surges, preserving measurement linearity. |
| DC-DC Converter Feedback Network | USB-C Power Delivery Protection |
Use Scenario: Providing accurate 5.1 V reference in the feedback divider of a buck converter regulating 5 V USB port output. IC Role / Device Role / Timing Role: Stable Zener element setting output voltage via resistor divider ratio; replaces higher-cost voltage references. Use Value: 294 mA IZM supports sufficient bias current margin for divider stability across line/load variations. |
Use Scenario: Overvoltage protection for 5 V VBUS line in portable accessories subjected to hot-plug transients and ESD events. IC Role / Device Role / Timing Role: Fast-acting shunt clamp absorbing surge energy before downstream USB controller ICs are stressed. Use Value: Class 3 ESD rating (>16 kV HBM) and 3 W peak pulse capability provide first-line defense without added components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMB5918BT3G | Same electrical specs and SMB package; lacks AEC−Q101 qualification and SZ-prefix automotive traceability | Not approved for automotive production; suitable for industrial or consumer designs without automotive compliance requirements | Select when AEC−Q101 is not mandated and cost sensitivity outweighs automotive qualification needs |
| BZX84-C5V1LT1G | Lower power (350 mW), SOT-23 package, 5.1 V ±5%, ZZT = 60 Ω @ 5 mA; no AEC−Q101 or Class 3 ESD rating | Targeted at low-current signal-level clamping; insufficient for 3 W power regulation or harsh-environment use | Choose only for space-constrained, low-power applications where thermal derating and automotive robustness are not required |
Compared with 1SMB5918BT3G and BZX84-C5V1LT1G, SZ1SMB5918BT3G uniquely delivers AEC−Q101 qualification, 3 W power handling, and Class 3 ESD in the SMB footprint-making it the sole option for automotive power rail stabilization where regulatory compliance and surge resilience are mandatory.
Availability
SZ1SMB5918BT3G is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor interfaces, DC-DC converter feedback networks, and USB-C power delivery protection requiring stable component supply and long-term lifecycle support.
Supply support for SZ1SMB5918BT3G 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.
SZ1SMB5918BT3G belongs to the 1SMB59xxBT3G/SZ1SMB59xxT3G family of 3 W Zener regulators designed specifically for high-reliability automotive and industrial voltage reference and overvoltage protection tasks.
FAQ
What is the Zener voltage tolerance of SZ1SMB5918BT3G?
The SZ1SMB5918BT3G has a nominal Zener voltage of 5.1 V with a tolerance of ±5%, meaning its actual reverse breakdown voltage falls between 4.84 V and 5.36 V when tested at IZT = 4 mA and TL = 30 °C. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the onsemi datasheet and applies to all units in the SZ1SMB5918BT3G production lot.
Is SZ1SMB5918BT3G suitable for automotive applications?
Yes, SZ1SMB5918BT3G is AEC−Q101 qualified and PPAP capable, with the "SZ" prefix indicating compliance for automotive and other applications requiring unique site and control change tracking. Its operating temperature range (−65 °C to +150 °C), Class 3 ESD rating (>16 kV HBM), and Pb−Free construction meet critical automotive reliability requirements, making SZ1SMB5918BT3G appropriate for under-hood and cabin ECUs.
What is the maximum power dissipation of SZ1SMB5918BT3G at room temperature?
SZ1SMB5918BT3G has a maximum steady-state power dissipation of 550 mW at TA = 25 °C, with a derating factor of 4.4 mW/°C above that temperature. This value is specified in the Maximum Ratings table and assumes use on an FR-4 board with the recommended footprint. At TL = 75 °C, the device supports up to 3.0 W, reflecting superior thermal conduction through the lead frame.
Does SZ1SMB5918BT3G have a defined forward voltage specification?
Yes, SZ1SMB5918BT3G specifies a maximum forward voltage (VF) of 1.5 V at IF = 200 mA(dc), as stated in the Electrical Characteristics summary on page 2 of the datasheet. This parameter is consistent across the entire 1SMB59xxBT3G series and confirms the device's suitability for bidirectional protection or dual-use as a rectifier in low-current paths where forward conduction may occur.
How is polarity identified on the SZ1SMB5918BT3G package?
SZ1SMB5918BT3G uses a cathode band marking on the body of the SMB (Case 403A) package to indicate polarity. As shown in the Mechanical Case Outline diagram on page 6, the band corresponds to the cathode terminal, while the unmarked end is the anode. This marking is visible under standard optical inspection and aligns with IPC-J-STD-020 placement guidelines for automated assembly verification.
SZ1SMB5918BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 5.1 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 4 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 2 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
SZ1SMB5918BT3G FAQ
1.How can I place an order for SZ1SMB5918BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5918BT3G 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 SZ1SMB5918BT3G reliable?
The price and inventory of SZ1SMB5918BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5918BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5918BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5918BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5918BT3G?
SZ1SMB5918BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5918BT3G 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 SZ1SMB5918BT3G?
For technical support, including SZ1SMB5918BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5918BT3G requirements.
6.How does Aetrix verify that SZ1SMB5918BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5918BT3G 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 SZ1SMB5918BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5918BT3G?
All SZ1SMB5918BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5918BT3G, 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 SZ1SMB5918BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5918BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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