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STMicroelectronics BZW50-18
- Part No.:
- BZW50-18
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- R-6, Axial
- Datasheet:
-
BZW50-18.pdf
- Description:
- TVS DIODE 18VWM 41.5VC R6
- Quantity:
- Payment:
- Shipping:
Inventory:689
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Product details
Overview
BZW50-18 from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power supply and interface lines. It features a 18 V stand-off voltage, 20 V minimum breakdown voltage at 1 mA, 32.2 V maximum clamping voltage at 155 A (10/1000 µs), 5000 W peak pulse power, and operates up to 175 °C junction temperature - deployed in industrial AC/DC adapters and telecom line cards.
For engineers reviewing the BZW50-18 datasheet, BZW50-18 pinout, BZW50-18 application, or BZW50-18 equivalent, key selection criteria include clamping voltage under 155 A surge, thermal derating above 25 °C, R6 package mounting compatibility, and IEC 61000-4-2/4-4 compliance verification for ESD and EFT immunity design.
Technical Context
The BZW50-18 uses planar silicon junction technology optimized for low leakage (<5 µA at 18 V) and stable dynamic resistance (0.065 Ω) under 10/1000 µs surges. Its unidirectional polarity enables asymmetric clamping on DC rails with cathode-anode orientation critical for correct surge current path.
Thermal performance is defined by junction-to-ambient thermal resistance (Rth(j-a)) of ~40 °C/W on FR4 PCB with 1 cm² copper per lead, and peak power derates linearly from 5000 W at 25 °C to 3700 W at 175 °C junction temperature per Figure 3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 18 V - Maximum continuous reverse operating voltage before significant leakage begins. |
| Breakdown Voltage (VBR) | 20 V min at 1 mA - Confirmed turn-on threshold ensuring reliable clamping onset during transients. |
| Clamping Voltage (VCL) | 32.2 V max at 155 A (10/1000 µs) - Limits protected circuit voltage during worst-case surge. |
| Peak Pulse Power (PPP) | 5000 W (10/1000 µs) - Sustains 5 kW surge energy without failure under standard waveform. |
| Junction Temperature Range | –55 °C to +175 °C - Enables operation in high-ambient environments like motor drives and outdoor power systems. |
| Leakage Current (IRM) | <5 µA at 18 V - Minimizes standby power loss in battery-backed or low-power circuits. |
| Dynamic Resistance (RD) | 0.065 Ω - Low impedance ensures minimal voltage overshoot during fast-rising transients. |
Pinout & Package
The BZW50-18 is housed in the axial-leaded R6 package (DO-201AD), with two terminals: anode and cathode. Cathode identified by a band marking; polarity must be observed for unidirectional clamping function.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Surge return path / low-side connection | Connected to ground or low-potential rail; completes conduction path during reverse-biased surge event. |
| Cathode | Protected line input / high-side connection | Connected to the line being protected (e.g., +12 V rail); conducts avalanche current when VIN exceeds VCL. |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature reliability | Rated for continuous operation up to 175 °C junction temperature with verified derating curve (Figure 3). |
| Low dynamic resistance | 0.065 Ω enables tight clamping control and reduces overshoot in fast-edge surge events. |
| IEC 61000-4-2/4-4 compliance | Validated to 30 kV contact/air discharge (ESD) and 4 kV electrical fast transient (EFT) immunity levels. |
| Planar junction construction | Delivers stable leakage (<5 µA) and repeatable VBR/VCL across temperature and lifetime. |
Applications
| Industrial AC/DC Power Supplies | Telecom Line Interface Cards |
|---|---|
Use Scenario: Protecting primary-side rectifier outputs and secondary-side 12–24 V DC rails against lightning-induced surges and switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed in parallel with load, conducting only during overvoltage events to clamp voltage below IC damage threshold. Use Value: Clamps to ≤32.2 V at 155 A, preventing MOSFET gate oxide rupture and optocoupler input damage in SMPS feedback paths. | Use Scenario: Shielding RS-485/RS-232 data lines and power inputs on remote terminal units (RTUs) exposed to field-installed wiring. IC Role / Device Role / Timing Role: Standoff-rated protector on +12 V bias rail and signal returns, absorbing coupled surges from adjacent power cables. Use Value: Withstands 5000 W (10/1000 µs) surges while maintaining <5 µA leakage-critical for low-power modem sleep modes. |
| Automotive Body Control Modules | Renewable Energy Inverter DC Links |
Use Scenario: Safeguarding 12 V microcontroller power inputs and CAN transceiver VCC pins against load-dump and jump-start transients. IC Role / Device Role / Timing Role: Primary overvoltage clamp on fused battery feed, activated within nanoseconds of voltage excursion beyond 18 V. Use Value: 175 °C rating allows placement near hot engine compartment components without thermal derating penalties. | Use Scenario: Protecting IGBT gate drivers and auxiliary power supplies in solar string inverters subjected to grid-switching transients. IC Role / Device Role / Timing Role: Secondary-level clamping on isolated 15–24 V auxiliary rails, supplementing primary MOV-based protection. Use Value: 0.065 Ω dynamic resistance ensures sub-100 ns response and prevents false triggering of undervoltage lockout during fast transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18A | Lower peak power (600 W vs. 5000 W), DO-214AA package, 28.2 V clamping at 21.3 A | Targeted for lower-energy signal-line protection; insufficient for power rail surges >1 kA | Select only for space-constrained PCBs where surge energy is limited to <1 kA (10/1000 µs) |
| P6KE18A | Same R6 package, but older glass-passivated junction; 33.2 V clamping at 151 A, higher leakage (~10 µA) | Legacy replacement with reduced thermal margin and less stable VCL over temperature | Acceptable for cost-sensitive industrial designs where 175 °C operation is not required |
Compared with SMBJ18A and P6KE18A, the BZW50-18 delivers 8× higher surge power handling, tighter clamping (32.2 V vs. ≥33.2 V), and superior high-temperature stability-making it the preferred choice for mission-critical power rail protection where reliability under sustained thermal stress is mandatory.
Availability
BZW50-18 is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, telecom line interface cards, and automotive body control modules requiring stable component supply across extended temperature and surge stress conditions.
Supply support for BZW50-18 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, sensing, and control solutions for industrial, automotive, and consumer markets.
The BZW50 series belongs to ST's high-power TVS diode product line, engineered specifically for robust, high-temperature surge immunity in industrial power conversion and infrastructure equipment.
FAQ
What is the maximum clamping voltage of BZW50-18 at 155 A?
The maximum clamping voltage is 32.2 V under a 10/1000 µs surge waveform at 155 A, measured at Tamb = 25 °C. This value increases with junction temperature at a coefficient of 9.2 × 10−4 per °C, per datasheet Equation 2.
Can BZW50-18 be used in bidirectional configurations?
No - BZW50-18 is unidirectional. For bidirectional protection at 18 V standoff, use the BZW50-18B variant, which provides symmetrical clamping in both polarities and shares identical power and thermal ratings.
What is the recommended PCB layout for thermal management?
Mount on FR4 with ≥1 cm² copper area per lead (minimum), using thermal vias to inner ground planes. Per Figure 12, this achieves ~40 °C/W Rth(j-a); doubling copper area reduces thermal resistance by ~30%, critical for sustained 175 °C operation.
Does BZW50-18 meet UL 497B certification?
Yes - it carries UL 497B file number QVGQ2.E136224, confirming suitability for primary circuit protection in telecommunications and industrial equipment per UL's surge protection device standard.
BZW50-18 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- R-6, Axial
- Series:
- BZW50, TRANSIL™
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 41.5V
- Current - Peak Pulse (10/1000µs):
- 1446A (1.446kA) (8/20µs)
- Power - Peak Pulse:
- 5000W (5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 11500pF @ 1MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- R-6
BZW50-18 FAQ
1.How can I place an order for BZW50-18 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZW50-18 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 BZW50-18 reliable?
The price and inventory of BZW50-18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZW50-18 is usually 5 days.
3.What payment methods are accepted for BZW50-18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZW50-18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZW50-18?
BZW50-18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZW50-18 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 BZW50-18?
For technical support, including BZW50-18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZW50-18 requirements.
6.How does Aetrix verify that BZW50-18 is sourced from the original manufacturer or authorized distributors?
All BZW50-18 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 BZW50-18 meets industry standards.
7.What is the process for return or replacement of BZW50-18?
All BZW50-18 units undergo pre-shipment inspection (PSI). If there is an issue with BZW50-18, 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 BZW50-18 part is unused and in its original packaging.
Return procedure for BZW50-18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZW50-18 Tags
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