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onsemi SZ1SMB5951BT3G
- Part No.:
- SZ1SMB5951BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5951BT3G.pdf
- Description:
- DIODE ZENER 120V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:6,911
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Product details
Overview
SZ1SMB5951BT3G from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 120 V, ±5% tolerance, 3.1 mA test current (IZT), and maximum dynamic impedance of 4500 Ω at IZT - used for precision voltage regulation and overvoltage protection in DC power supplies and automotive control modules.
For engineers reviewing the SZ1SMB5951BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include its 120 V Zener rating, 3 W steady-state power dissipation at TL = 75°C, AEC−Q101 qualification, and SMB package compatibility with automated SMT assembly.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to clamp voltage at its specified VZ. It exhibits a positive temperature coefficient above ~6 V, with θVZ ≈ +0.11 mV/°C at 120 V per Figure 4.
Designed for stable DC regulation under fixed-current bias, it supports surge power up to 100 W for 10 ms (non-repetitive) and maintains leakage current ≤0.25 μA at VR = 91.2 V per electrical characteristics table.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 114–126 V (±5% tolerance at IZT = 3.1 mA; defines regulated output voltage range) |
| Power Dissipation (PD) | 3.0 W at TL = 75°C (requires thermal pad or heatsinking on PCB for full rating) |
| Zener Impedance (ZZT) | ≤4500 Ω at IZT = 3.1 mA (limits regulation error under load transients) |
| Leakage Current (IR) | ≤0.25 μA at VR = 91.2 V (ensures low standby power loss in high-impedance bias networks) |
| Forward Voltage (VF) | ≤1.5 V at IF = 200 mA (supports use as polarity-sensitive clamp in bidirectional protection schemes) |
| Thermal Resistance (RJL) | 40 °C/W junction-to-lead (enables direct thermal path to copper pour or thermal via) |
| AEC−Q101 Qualified | Yes (validates reliability for automotive electronics including engine control units and body modules) |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with modified L-bend leads, cathode indicated by polarity band, UL 94 V−0 flammability rating, Pb-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Low-side reference node | Connected to ground or lower-potential rail during Zener operation; carries full IZM current in regulation mode |
| Cathode | Reverse breakdown terminal / Regulated output node | Provides stable 120 V reference when reverse-biased; must be connected to supply rail through current-limiting resistor |
Key Features
| Feature | Design Value |
|---|---|
| ESD robustness | Class 3 HBM (>16 kV) enables handling in unshielded assembly environments without additional ESD mitigation |
| Flat handling surface | Ensures consistent pick-and-place accuracy during automated SMT placement on high-density PCBs |
| Top/bottom board mounting | Package symmetry allows routing flexibility - no orientation constraint relative to adjacent components |
| Pb-free construction | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 reflow profiles |
| Modified L-bend leads | Increases solder joint area and mechanical retention strength on FR-4 substrates |
Applications
| Automotive Engine Control Unit (ECU) | Industrial DC Power Supply Monitoring |
|---|---|
Use Scenario: Clamping transient spikes on 12 V battery-supplied microcontroller I/O lines during load dump events. IC Role / Device Role / Timing Role: Voltage clamp protecting MCU GPIO pins from >100 V surges. Use Value: Prevents latch-up or permanent damage using its 120 V Zener threshold and 100 W peak surge capability. |
Use Scenario: Providing stable reference for overvoltage detection circuitry in 48 V telecom rectifier modules. IC Role / Device Role / Timing Role: Precision voltage reference enabling comparator-based shutdown at 120 V ±5%. Use Value: Enables accurate trip point with minimal drift due to its tight 5% tolerance and low IR leakage. |
| Medical Imaging Power Rail Protection | Renewable Energy Inverter DC Link Sensing |
Use Scenario: Protecting analog front-end circuits in X-ray generator control boards from switching transients. IC Role / Device Role / Timing Role: High-voltage shunt regulator absorbing energy during IGBT turn-off overshoot. Use Value: Maintains signal integrity with <0.25 μA leakage at 91.2 V, minimizing offset errors in precision amplifiers. |
Use Scenario: Biasing voltage dividers for isolated DC link voltage sensing in solar inverters operating up to 1000 V bus. IC Role / Device Role / Timing Role: Reference stabilizer ensuring consistent divider ratio across temperature. Use Value: Delivers predictable regulation with +0.11 mV/°C tempco, reducing calibration burden in field-deployed units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMB5951BT3G | No AEC−Q101 qualification; identical electrical specs and SMB package | Not approved for automotive production; suitable for industrial/commercial designs only | Select when AEC−Q101 compliance is not required and cost optimization is prioritized |
| BZX84-C120LT1G | 300 mW rating, SOT-23 package, 120 V nominal, ±5%; higher ZZT (1000 Ω typical) | Limited to low-power bias networks; unsuitable for 3 W continuous dissipation | Choose only for space-constrained, low-current reference applications where thermal margin is sufficient |
Compared with SZ1SMB5951BT3G, 1SMB5951BT3G offers identical performance without automotive qualification, while BZX84-C120LT1G trades power handling and thermal capability for footprint reduction - making the former a drop-in alternative for non-automotive use, and the latter a functional substitute only in sub-100 mW bias circuits.
Availability
SZ1SMB5951BT3G is available at Aetrix Electronics and suitable for automotive ECUs, industrial power supplies, medical imaging subsystems, and renewable energy inverters requiring stable component supply with AEC−Q101 assurance and long-term lifecycle support.
Supply support for SZ1SMB5951BT3G 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, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
SZ1SMB5951BT3G belongs to the 1SMB59xxBT3G/SZ1SMB59xxT3G series - engineered for high-reliability voltage regulation in harsh environments, especially where AEC−Q101 validation and 3 W power handling are mandatory.
FAQ
What is the Zener voltage tolerance for SZ1SMB5951BT3G?
The SZ1SMB5951BT3G has a nominal Zener voltage of 120 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 114 V and 126 V when measured at IZT = 3.1 mA and TL = 30°C. This tolerance is explicitly defined in the Electrical Characteristics table on page 3 of the onsemi datasheet and applies to all devices in the 1SMB59xxBT3G/SZ1SMB59xxT3G family.
Is SZ1SMB5951BT3G suitable for automotive applications?
Yes, SZ1SMB5951BT3G is AEC−Q101 qualified and PPAP capable, as confirmed in the Features section of the onsemi datasheet. The "SZ" prefix denotes automotive-grade variants meeting stringent reliability, testing, and traceability requirements - making SZ1SMB5951BT3G appropriate for engine control units, body electronics, and ADAS power domains.
What is the maximum steady-state power dissipation for SZ1SMB5951BT3G?
SZ1SMB5951BT3G delivers 3.0 W maximum steady-state power dissipation at TL = 75°C (junction-to-lead), with linear derating of 25 mW/°C above that temperature. At TA = 25°C, its rated power drops to 550 mW due to higher thermal resistance to ambient (226 °C/W), as specified in the Maximum Ratings table on page 1 of the datasheet.
How does the temperature coefficient affect SZ1SMB5951BT3G's regulation accuracy?
SZ1SMB5951BT3G exhibits a positive temperature coefficient of approximately +0.11 mV/°C at 120 V, as shown in Figure 4 of the datasheet. This means its Zener voltage increases by ~0.11 mV per degree Celsius rise in junction temperature - a critical factor when designing for wide-temperature-range operation in automotive or industrial settings.
Can SZ1SMB5951BT3G be used in place of lower-voltage Zeners like SZ1SMB5922BT3G?
No - SZ1SMB5951BT3G is not interchangeable with lower-voltage variants such as SZ1SMB5922BT3G (7.5 V nominal) due to fundamental differences in Zener voltage, test current, impedance, and thermal behavior. Each part in the 1SMB59xxBT3G/SZ1SMB59xxT3G series is optimized for its specific voltage grade; substituting across grades invalidates regulation performance and may cause system failure.
SZ1SMB5951BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 120 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 380 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 91.2 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
SZ1SMB5951BT3G FAQ
1.How can I place an order for SZ1SMB5951BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5951BT3G 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 SZ1SMB5951BT3G reliable?
The price and inventory of SZ1SMB5951BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5951BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5951BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5951BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5951BT3G?
SZ1SMB5951BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5951BT3G 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 SZ1SMB5951BT3G?
For technical support, including SZ1SMB5951BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5951BT3G requirements.
6.How does Aetrix verify that SZ1SMB5951BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5951BT3G 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 SZ1SMB5951BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5951BT3G?
All SZ1SMB5951BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5951BT3G, 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 SZ1SMB5951BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5951BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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