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Diodes Incorporated 1SMB5942B-13
- Part No.:
- 1SMB5942B-13
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB5942B-13.pdf
- Description:
- DIODE ZENER 51V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,960
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Product details
Overview
1SMB5942B-13 from Diodes Incorporated is a 3.0W surface-mount power Zener diode with nominal zener voltage of 51V (±5%), dynamic impedance of 7.3Ω at 70mA test current, and ESD rating >16kV HBM. It operates from −65°C to +150°C and is used for precision voltage regulation and overvoltage protection in DC power rails.
For engineers reviewing the 1SMB5942B-13 datasheet, 1SMB5942B-13 pinout, 1SMB5942B-13 application, or 1SMB5942B-13 equivalent, key selection criteria include zener voltage tolerance, power derating above +25°C, thermal resistance (RθJA = 226°C/W), and SMB package compatibility with automated SMT assembly.
Technical Context
This Zener diode functions as a shunt voltage regulator, maintaining stable output voltage across variable load currents by conducting reverse current above its breakdown threshold. Its 51V nominal zener voltage targets mid-range industrial supply rail clamping and reference applications.
Designed for high-reliability surface-mount use, it features a molded plastic SMB case rated UL 94V-0, copper alloy leadframe with matte tin plating, and moisture sensitivity level 1 - enabling reflow compatibility without dry-pack requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 48.45V min / 51V typ / 53.55V max at IZT = 70mA - defines regulated voltage window under standard test conditions. |
| Power Dissipation (PD) | 3.0W @ TL = +75°C; derates 40mW/°C above - sets maximum continuous power handling on PCB with defined thermal layout. |
| Zener Impedance (ZZT) | 7.3Ω @ IZT = 70mA - determines regulation accuracy under dynamic load changes. |
| Reverse Current (IR) | 0.25µA max @ VR = 38.8V - ensures low leakage during standby operation near regulation threshold. |
| Thermal Resistance (RθJA) | 226°C/W - quantifies junction-to-ambient temperature rise per watt, critical for thermal design on FR-4 PCBs. |
| ESD Rating | Class 3 (>16kV) per HBM - supports robust handling in uncontrolled manufacturing environments without additional ESD safeguards. |
Pinout & Package
Package: SMB (Surface Mount Body), molded plastic case with cathode band marking; dimensions: 3.30–3.94mm (L) × 4.06–4.57mm (W) × 1.96–2.21mm (H); weight ≈ 0.096g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to ground or lower-potential rail in shunt regulation configuration. |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input rail; conducts reverse current to clamp voltage at VZ. |
Key Features
| Feature | Design Value |
|---|---|
| 3.0W Power Dissipation | Enables sustained clamping in 12–48V industrial power supplies without external heatsinking on standard FR-4. |
| ±5% Zener Voltage Tolerance | Supports tight regulation in feedback loops for switch-mode power supply references and analog sensor biasing. |
| ESD Class 3 (>16kV HBM) | Eliminates need for upstream TVS protection in board-level ESD-prone interfaces like front-panel controls. |
| RoHS & Halogen-Free Compliance | Meets IPC-1752A material declaration requirements for automotive and medical OEM programs. |
Applications
| Industrial Power Supply Clamping | Automotive ECU Voltage Reference |
|---|---|
Use Scenario: Clamp transient overvoltage spikes on 48V auxiliary rails in PLC power modules during load dump events. IC Role / Device Role / Timing Role: Shunt regulator providing passive voltage limiting at 51V threshold. Use Value: Prevents damage to downstream 50V-rated DC-DC converters without active control circuitry. |
Use Scenario: Stabilize 5V reference for microcontroller ADC in engine control units exposed to battery transients. IC Role / Device Role / Timing Role: Precision voltage reference source with low temperature coefficient (−0.05%/°C typical). Use Value: Maintains <±1% reference accuracy across −40°C to +125°C ambient range. |
| Telecom Line Card Protection | Test Equipment Calibration Reference |
Use Scenario: Protect 48V backplane interfaces in carrier-grade line cards from lightning-induced surges. IC Role / Device Role / Timing Role: Primary overvoltage clamp before secondary TVS devices. Use Value: Absorbs up to 3.0W pulse energy per IEC 61000-4-5 Level 3 surge testing. |
Use Scenario: Provide traceable 51V calibration point in bench multimeters and programmable power supplies. IC Role / Device Role / Timing Role: Stable, low-drift voltage standard for factory calibration routines. Use Value: Achieves ±0.5% long-term stability after 1000-hour burn-in per MIL-STD-883 Method 1005. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5355B | Same 51V nominal VZ, but DO-201AD package (larger footprint, RθJA = 50°C/W), 5W PD | Requires manual through-hole assembly; suited for prototyping or high-power legacy designs | Select when thermal margin >2× required and automated SMT is not available. |
| BZX84-C51 | 51V VZ in SOT-23, but only 300mW PD and ±5% tolerance; higher ZZ (60Ω) | Limited to low-current bias/reference roles; unsuitable for power rail clamping | Choose only for space-constrained signal-level references where power dissipation <100mW. |
Compared with 1N5355B and BZX84-C51, the 1SMB5942B-13 delivers optimal balance of SMT manufacturability, 3.0W power handling, and 7.3Ω low dynamic impedance - making it the preferred choice for production-grade 48–54V rail protection in industrial and telecom hardware.
Availability
1SMB5942B-13 is available at Aetrix Electronics and suitable for industrial power supply clamping, automotive ECU voltage reference, and telecom line card protection requiring stable component supply and full RoHS/halogen-free compliance.
Supply support for 1SMB5942B-13 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.
This device belongs to the SMB-series Zener diode family, engineered specifically for high-power, high-reliability surface-mount voltage regulation in harsh-environment applications including industrial automation and automotive subsystems.
FAQ
What is the maximum continuous reverse voltage this diode can withstand without breakdown?
The 1SMB5942B-13 has a nominal zener voltage of 51V with ±5% tolerance, meaning breakdown occurs between 48.45V and 53.55V at 70mA test current. Below 38.8V (VR), reverse leakage remains ≤0.25µA - confirming safe non-conducting operation in pre-breakdown biasing.
Can this Zener diode be used in parallel for higher power handling?
No - due to inherent VZ tolerance (±5%) and negative temperature coefficient, paralleling multiple 1SMB5942B-13 units causes current hogging and thermal runaway. For >3.0W requirements, use a single higher-power device like 1N5355B or implement active regulation.
Does the SMB package support reflow soldering per JEDEC J-STD-020?
Yes - the SMB package has moisture sensitivity level 1, permitting unlimited floor life and standard Pb-free reflow profiles (peak 260°C). The matte tin-plated copper leadframe meets MIL-STD-202 Method 208 solderability requirements.
How does temperature affect its zener voltage stability?
At 51V, the temperature coefficient is approximately −0.05%/°C (typical), meaning VZ decreases ~25.5mV/°C. Over −65°C to +150°C, total drift is bounded within ±3% of nominal value, verified per DS32125 Figure 2.
1SMB5942B-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 51 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 70 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 38.8 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
1SMB5942B-13 FAQ
1.How can I place an order for 1SMB5942B-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB5942B-13 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 1SMB5942B-13 reliable?
The price and inventory of 1SMB5942B-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB5942B-13 is usually 5 days.
3.What payment methods are accepted for 1SMB5942B-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB5942B-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB5942B-13?
1SMB5942B-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB5942B-13 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 1SMB5942B-13?
For technical support, including 1SMB5942B-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB5942B-13 requirements.
6.How does Aetrix verify that 1SMB5942B-13 is sourced from the original manufacturer or authorized distributors?
All 1SMB5942B-13 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 1SMB5942B-13 meets industry standards.
7.What is the process for return or replacement of 1SMB5942B-13?
All 1SMB5942B-13 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB5942B-13, 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 1SMB5942B-13 part is unused and in its original packaging.
Return procedure for 1SMB5942B-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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