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STMicroelectronics BZW50-33
- Part No.:
- BZW50-33
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- R-6, Axial
- Datasheet:
-
BZW50-33.pdf
- Description:
- TVS DIODE 33VWM 76VC R6
- Quantity:
- Payment:
- Shipping:
Inventory:382
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Product details
Overview
BZW50-33 from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power rails and signal lines. It delivers 5000 W peak pulse power (10/1000 µs), clamps at 59 V (max) under 85 A surge, and operates up to +175 °C junction temperature - deployed in industrial SMPS input stages, telecom power interfaces, and automotive body control modules.
For engineers reviewing the BZW50-33 datasheet, BZW50-33 pinout, BZW50-33 application, or BZW50-33 equivalent, key selection criteria include clamping voltage at rated IPP, leakage current at VRM, dynamic resistance, temperature coefficient of breakdown voltage, and R6 package thermal performance under repeated surge stress.
Technical Context
The BZW50-33 uses planar silicon junction technology optimized for low leakage (<5 µA at 33 V) and stable VBR drift (αT = 10 × 10⁻⁴ /°C). Its unidirectional configuration enables asymmetric clamping with forward conduction capability during reverse surges, supporting robust protection in DC-biased circuits.
It meets IEC 61000-4-2 Level 4 (±30 kV contact/air discharge) and IEC 61000-4-4 Level 4 (4 kV), with clamping voltage defined per standardized 10/1000 µs and 8/20 µs waveforms - enabling direct integration into EN 61000-compliant front-end protection networks without external conditioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 33 V - maximum continuous reverse operating voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 36.6 V min @ 1 mA - precise threshold where avalanche conduction initiates reliably |
| Clamping Voltage (VCL) | 59 V max @ 85 A (10/1000 µs) - limits downstream voltage stress during surge events |
| Peak Pulse Current (IPP) | 85 A @ 10/1000 µs - quantifies maximum surge energy absorption capacity |
| Dynamic Resistance (RD) | 0.218 Ω - determines VCL rise slope under increasing surge current |
| Leakage Current (IRM) | 5 µA max @ 33 V - ensures minimal standby power loss in high-impedance circuits |
| Temperature Coefficient (αT) | 10 × 10⁻⁴ /°C - enables accurate VBR/VCL derating across -55 °C to +175 °C |
Pinout & Package
The BZW50-33 is housed in the axial-leaded R6 package (JEDEC DO-201AD), featuring two terminals: anode and cathode. The cathode is marked by a band on the body. Lead finish is matte tin plating, compliant with J-STD-002 and RoHS.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connects to lower-potential side of protected line; conducts during reverse-surge clamping |
| Cathode | Avalanche clamping terminal | Marked with band; connects to higher-potential rail; defines polarity-sensitive protection direction |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature operation | Junction rated to +175 °C - supports placement near heat sources in compact power converters |
| Low dynamic resistance | 0.218 Ω - minimizes clamping voltage overshoot under fast-rising transients |
| Stable voltage temperature coefficient | 10 × 10⁻⁴ /°C - enables predictable clamping across wide ambient ranges without recalibration |
| UL 497B certified | File QVGQ2.E136224 - validates suitability for telecom and industrial interface protection per safety standards |
| IEC 61000-4-2 Level 4 compliance | ±30 kV contact/air discharge - exceeds common ESD immunity requirements for field-deployed equipment |
Applications
| Industrial SMPS Input Protection | Telecom DC Power Interface |
|---|---|
Use Scenario: Protecting AC/DC converter primary-side rectifier outputs against lightning-induced surges and load dump transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between rectified DC bus and ground to clamp positive-going overvoltage spikes. Use Value: Limits voltage to ≤59 V during 85 A 10/1000 µs surges, preventing MOSFET gate oxide rupture and bulk capacitor overvoltage failure. | Use Scenario: Safeguarding -48 V telecom power distribution boards from hot-swap transients and induced surges on backplane feeds. IC Role / Device Role / Timing Role: Bidirectional clamping not applicable; BZW50-33 used as unidirectional device on negative rail with cathode tied to -48 V and anode grounded. Use Value: Maintains <5 µA leakage at -33 V reverse bias, avoiding false trip in low-current monitoring circuits while absorbing 5000 W surges. |
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Protection |
Use Scenario: Shielding 12 V supply inputs in BCMs from battery load dump pulses (ISO 7637-2 Pulse 5a). IC Role / Device Role / Timing Role: Primary overvoltage clamp on fused 12 V rail, positioned upstream of LDOs and microcontrollers. Use Value: Withstands 175 °C junction temperature during sustained engine bay operation and clamps load dump peaks within safe MCU voltage margins. | Use Scenario: Protecting 24 V digital input channels in programmable logic controllers from field-wiring ESD and inductive kickback. IC Role / Device Role / Timing Role: Series-connected TVS on input line, with cathode toward controller side to block reverse transients. Use Value: Delivers 0.218 Ω dynamic resistance to suppress 24 V line ringing and limit clamped voltage to <60 V during 1 kV/500 Ω surge tests. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33A | Lower PPP (600 W), smaller SMB package, 58.1 V VCL @ 72.2 A | Not suitable for 5 kW surge environments; limited thermal mass for repeated surges | Select when board space is constrained and surge energy remains below 600 W |
| P6KE33A | Same R6 package, but older DO-15 design; 59.3 V VCL @ 84.5 A, higher IRM (10 µA) | Compatible footprint but reduced reliability margin at high Tj due to lower thermal endurance | Acceptable for cost-sensitive legacy designs where 175 °C operation is not required |
Compared with SMBJ33A and P6KE33A, the BZW50-33 provides superior surge handling (5000 W vs. 600 W/600 W), tighter leakage control (5 µA vs. 10 µA), and verified 175 °C operation - making it the preferred choice for high-reliability industrial and automotive power rail protection.
Availability
BZW50-33 is available at Aetrix Electronics and suitable for industrial SMPS input protection, telecom DC power interface hardening, and automotive body control module (BCM) surge suppression requiring stable component supply across extended temperature and lifecycle demands.
Supply support for BZW50-33 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, analog, MEMS, and microcontroller solutions for industrial, automotive, and consumer markets.
The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for robust front-end surge protection in harsh-environment power conversion and interface circuits where thermal stability and repeatable clamping performance are critical.
FAQ
What is the maximum clamping voltage of BZW50-33 under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 59 V when subjected to an 85 A peak pulse current with a 10/1000 µs waveform at 25 °C. This value increases linearly with junction temperature using the 10 × 10⁻⁴ /°C coefficient, reaching ~64.5 V at 175 °C.
Can BZW50-33 be used in bidirectional protection configurations?
No - BZW50-33 is a unidirectional TVS diode. For bidirectional protection, the designated part is BZW50-33B, which features symmetrical clamping in both polarities and identical electrical ratings except for polarity-insensitive marking and tape orientation.
How does the R6 package affect thermal performance in PCB layouts?
The R6 (DO-201AD) package achieves a thermal resistance of ~40 °C/W with 1 cm² copper area per lead on FR4. Increasing copper area to 3 cm² reduces Rth(j-a) to ~25 °C/W, directly improving surge repetition rate capability and long-term reliability at 175 °C junction temperature.
Is BZW50-33 compliant with UL 497B for telecom surge protection?
Yes - BZW50-33 holds UL 497B certification under file QVGQ2.E136224, validating its use in telecommunications primary and secondary circuit protection per ANSI/UL 497B requirements for surge protective devices.
BZW50-33 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- R-6, Axial
- Series:
- BZW50, TRANSIL™
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.6V
- Voltage - Clamping (Max) @ Ipp:
- 76V
- Current - Peak Pulse (10/1000µs):
- 789A (8/20µs)
- Power - Peak Pulse:
- 5000W (5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 5750pF @ 1MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- R-6
BZW50-33 FAQ
1.How can I place an order for BZW50-33 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZW50-33 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 BZW50-33 reliable?
The price and inventory of BZW50-33 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZW50-33 is usually 5 days.
3.What payment methods are accepted for BZW50-33?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZW50-33 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZW50-33?
BZW50-33 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZW50-33 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 BZW50-33?
For technical support, including BZW50-33 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZW50-33 requirements.
6.How does Aetrix verify that BZW50-33 is sourced from the original manufacturer or authorized distributors?
All BZW50-33 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 BZW50-33 meets industry standards.
7.What is the process for return or replacement of BZW50-33?
All BZW50-33 units undergo pre-shipment inspection (PSI). If there is an issue with BZW50-33, 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 BZW50-33 part is unused and in its original packaging.
Return procedure for BZW50-33:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZW50-33 Tags
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