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onsemi 1SMB5951BT3
- Part No.:
- 1SMB5951BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5951BT3.pdf
- Description:
- DIODE ZENER 120V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:8,311
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Product details
Overview
1SMB5951BT3 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 3.1 Ω at IZT - used for precision voltage regulation and overvoltage protection in DC power rails and industrial control interfaces.
For engineers reviewing the 1SMB5951BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage stability across temperature, low leakage (<0.25 μA @ 91.2 V), surge power handling (up to 4500 W peak), thermal resistance (226 °C/W), and AEC−Q101 qualification status for automotive-grade reliability.
Technical Context
This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown above its specified Zener voltage (114–126 V) while maintaining stable clamping under steady-state and transient conditions. Its SMB package enables high-power dissipation (3.0 W @ TL = 75°C) with derating to 550 mW at TA = 25°C.
It features Class 3 ESD robustness (>16 kV HBM), UL 94 V−0 flammability rating, Pb−Free construction, and polarity band marking for unambiguous cathode identification. Thermal resistance from junction-to-ambient is 226 °C/W on FR−4 board with recommended footprint.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 114 V min / 120 V nom / 126 V max - defines precise clamping threshold for 120 V rail protection |
| Zener Test Current (IZT) | 3.1 mA - operating point where VZ and dynamic impedance are specified |
| Dynamic Impedance (ZZT) | 3.1 Ω max @ IZT - ensures minimal voltage deviation under load current variation |
| Reverse Leakage (IR) | 0.25 μA max @ 91.2 V - guarantees low standby power loss in high-impedance bias networks |
| Max DC Zener Current (IZM) | 12 A - determines maximum continuous current before thermal runaway |
| Power Dissipation (PD) | 3.0 W @ TL = 75°C - supports high-reliability operation with heatsink-assisted lead conduction |
| Thermal Resistance (RJA) | 226 °C/W - requires careful PCB copper area design to maintain TJ < 150°C |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with modified L-bend leads, cathode indicated by polarity band, UL 94 V−0 rated, void-free transfer-molded construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reference ground node | Connected to system ground or lower-potential rail; establishes reference for reverse-biased operation |
| Cathode | Reverse breakdown terminal / Regulated output node | Connected to protected node; clamps voltage to VZ when reverse voltage exceeds breakdown threshold |
Key Features
| Feature | Design Value |
|---|---|
| 3.0 W steady-state power rating | Enables robust overvoltage suppression in 120 V DC systems without external heatsinking |
| ±5% Zener voltage tolerance | Reduces binning requirements and simplifies BOM management for 120 V regulation |
| ESD rating >16 kV (HBM) | Eliminates need for additional ESD protection in front-end power interfaces |
| AEC−Q101 qualified (SZ variant) | Validated for automotive power supply monitoring and body electronics applications |
| Pb−Free (RoHS-compliant) construction | Meets global environmental compliance mandates without performance trade-offs |
Applications
| Industrial Power Supply Monitoring | Automotive Battery Management |
|---|---|
Use Scenario: Monitoring 120 V intermediate bus in programmable logic controller (PLC) power modules. IC Role / Device Role / Timing Role: Zener voltage reference and overvoltage clamp protecting downstream DC/DC converters. Use Value: Maintains regulation within ±5% across −65°C to +150°C ambient, enabling reliable operation in factory-floor environments. |
Use Scenario: Overvoltage protection for 48 V–120 V hybrid vehicle auxiliary battery circuits. IC Role / Device Role / Timing Role: Transient voltage suppressor during load-dump events per ISO 7637-2. Use Value: Withstands 4500 W non-repetitive surge (10/1000 μs waveform), meeting automotive surge immunity requirements. |
| Telecom DC Power Interface | Test Equipment Reference Calibration |
Use Scenario: Input-stage voltage clamping in 110–130 V telecom rectifier outputs. IC Role / Device Role / Timing Role: Precision Zener reference stabilizing feedback loop of isolated flyback regulator. Use Value: Low 3.1 Ω dynamic impedance minimizes output voltage ripple under dynamic load steps. |
Use Scenario: Stable voltage reference in portable multimeter calibration circuitry. IC Role / Device Role / Timing Role: Two-terminal passive reference providing traceable 120 V benchmark. Use Value: <0.25 μA leakage at 91.2 V ensures negligible current draw from high-impedance reference dividers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5951B | Same Zener voltage range (114–126 V), but DO-41 through-hole package; higher RJA (500 °C/W) | Requires PCB through-hole mounting and larger board area; unsuitable for high-density SMT designs | Select when legacy through-hole assembly or manual prototyping is required |
| SZ1SMB5951BT3G | Identical electrical specs and SMB package; differs only in AEC−Q101 qualification and SZ prefix for automotive traceability | Required for automotive PPAP submissions; supports full automotive change control and lot traceability | Select for automotive production programs requiring AEC−Q101 documentation and process validation |
Compared with 1SMB5951BT3, 1N5951B trades SMT compatibility for easier hand-soldering and lower cost in low-volume builds, while SZ1SMB5951BT3G adds automotive-grade process controls and documentation without altering electrical behavior - making it the direct upgrade path for automotive OEM designs.
Availability
1SMB5951BT3 is available at Aetrix Electronics and suitable for industrial power supply monitoring, automotive battery management, telecom DC interface protection, and test equipment reference calibration requiring stable component supply and long-term obsolescence mitigation.
Supply support for 1SMB5951BT3 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.
The 1SMB59xxBT3 series is part of onsemi's high-reliability Zener regulator portfolio designed for precision voltage reference and transient overvoltage protection in harsh-environment applications demanding AEC−Q101 qualification and extended temperature operation.
FAQ
What is the Zener voltage tolerance of the 1SMB5951BT3?
The 1SMB5951BT3 has a ±5% Zener voltage tolerance, meaning its nominal 120 V breakdown voltage falls between 114 V and 126 V at the specified test current of 3.1 mA. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official datasheet and applies across the full operating temperature range of −65°C to +150°C.
Is the 1SMB5951BT3 RoHS-compliant and lead-free?
Yes, the 1SMB5951BT3 is RoHS-compliant and Pb−Free, as indicated by the "G" suffix in its ordering designation and explicitly stated in the Package and Ordering Information section. The device meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements and supports standard reflow soldering profiles up to 260°C for 10 seconds.
What is the maximum surge power rating for the 1SMB5951BT3?
The 1SMB5951BT3 supports a peak non-repetitive surge power of 4500 W, measured using a 10/1000 μs exponential pulse waveform at TJ = 25°C prior to the pulse. This value corresponds to its maximum DC Zener current of 12 A and is validated in Figure 2 ("Maximum Surge Power") of the datasheet.
Does the 1SMB5951BT3 have AEC−Q101 qualification?
No - the 1SMB5951BT3 itself is not AEC−Q101 qualified. However, its automotive-grade counterpart, the SZ1SMB5951BT3G, carries full AEC−Q101 qualification and PPAP capability. Both share identical electrical specifications and SMB packaging, differing only in process controls and traceability documentation required for automotive production.
What is the thermal resistance from junction-to-ambient (RJA) for the 1SMB5951BT3?
The 1SMB5951BT3 has a thermal resistance from junction-to-ambient of 226 °C/W when mounted on an FR−4 board using the recommended footprint. This value assumes zero airflow and is specified at TA = 25°C; derating begins above 25°C at 4.4 mW/°C, limiting usable power to 550 mW at room temperature.
1SMB5951BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB5951BT3 FAQ
1.How can I place an order for 1SMB5951BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5951BT3 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 1SMB5951BT3 reliable?
The price and inventory of 1SMB5951BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5951BT3 is usually 5 days.
3.What payment methods are accepted for 1SMB5951BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5951BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5951BT3?
1SMB5951BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5951BT3 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 1SMB5951BT3?
For technical support, including 1SMB5951BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5951BT3 requirements.
6.How does Aetrix verify that 1SMB5951BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB5951BT3 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 1SMB5951BT3 meets industry standards.
7.What is the process for return or replacement of 1SMB5951BT3?
All 1SMB5951BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5951BT3, 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 1SMB5951BT3 part is unused and in its original packaging.
Return procedure for 1SMB5951BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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