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STMicroelectronics BZW50-68B
- Part No.:
- BZW50-68B
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- R-6, Axial
- Datasheet:
-
BZW50-68B.pdf
- Description:
- TVS DIODE 68VWM 157VC R6
- Quantity:
- Payment:
- Shipping:
Inventory:1,351
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Product details
Overview
BZW50-68B from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power supply and interface lines. It features a 68 V stand-off voltage, 75.6 V minimum breakdown voltage at 1 mA, 121 V clamping voltage at 41 A (10/1000 µs), 5000 W peak pulse power, and operates up to 175 °C junction temperature - deployed in telecom AC/DC front-ends and industrial I/O protection.
For engineers reviewing the BZW50-68B datasheet, BZW50-68B pinout, BZW50-68B application, or BZW50-68B equivalent, key selection criteria include clamping voltage margin vs. protected IC VMAX, bidirectional polarity handling for AC-coupled lines, thermal derating above 25 °C, and dynamic resistance (0.913 Ω) impact on voltage overshoot during fast transients.
Technical Context
The BZW50-68B uses planar silicon junction technology optimized for low leakage (<5 µA at 68 V) and stable clamping over temperature (αT = 10.5 × 10−4/°C). Its bidirectional structure enables symmetrical surge suppression on AC signals or differential buses without polarity constraints.
It delivers 382 A peak pulse current under 8/20 µs waveform (157 V clamping), with dynamic resistance of 0.192 Ω - critical for limiting voltage overshoot during sub-microsecond ESD events per IEC 61000-4-2 (30 kV contact/air) and IEC 61000-4-4 level 4 (4 kV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 68 V - maximum continuous reverse operating voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 75.6 V min @ 1 mA - guaranteed conduction onset threshold for reliable triggering |
| Clamping Voltage (VCL) | 121 V @ 41 A, 10/1000 µs - peak voltage seen by protected circuit during worst-case surge |
| Peak Pulse Power (PPP) | 5000 W @ 10/1000 µs - energy-handling capacity for lightning-induced surges |
| Dynamic Resistance (RD) | 0.913 Ω - determines voltage rise slope during fast transients; lower value improves clamping fidelity |
| Junction Temperature Range | −55 °C to +175 °C - supports operation in harsh environments like motor drives and outdoor power systems |
| Leakage Current (IRM) | ≤5 µA @ 68 V - ensures minimal standby power loss and signal integrity in high-impedance circuits |
Pinout & Package
Supplied in R6 axial-leaded package (JEDEC DO-201AD), with two terminals: anode and cathode marked by a band on unidirectional variants; BZW50-68B is bidirectional and lacks polarity marking - both leads are functionally identical.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Lead 1) | Surge current entry (positive half-cycle) | Conducts during positive transients; forms symmetrical path with cathode in bidirectional mode |
| Cathode (Lead 2) | Surge current entry (negative half-cycle) | Conducts during negative transients; enables full-wave clamping without external polarity management |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature reliability | Rated for continuous operation up to 175 °C junction temperature - maintains clamping stability in enclosed power supplies |
| Low dynamic resistance | 0.913 Ω (10/1000 µs) - minimizes voltage overshoot during fast-rising surges, improving system-level immunity |
| IEC 61000-4-2 compliance | Withstands 30 kV air/contact discharge - exceeds Level 4 ESD immunity for industrial field interfaces |
| Planar junction construction | Enables tight parameter distribution and low leakage (<5 µA) - critical for precision analog and high-impedance sensor inputs |
| UL 497B certified | QVGQ2.E136224 listing - validates suitability for telecom and data line surge protection per safety standards |
Applications
| AC/DC Power Supply Input Protection | Industrial Fieldbus Interface Protection |
|---|---|
Use Scenario: Protecting rectified AC input stages of switch-mode power supplies against lightning-induced surges and load dump transients. IC Role / Device Role / Timing Role: Bidirectional TVS clamp placed across bulk capacitor input to limit transient voltage to ≤121 V during 41 A 10/1000 µs surge. Use Value: Prevents MOSFET gate oxide rupture and bulk capacitor overvoltage failure while maintaining <5 µA standby leakage. | Use Scenario: Safeguarding RS-485 transceivers connected to long outdoor cables exposed to induced surges and ESD. IC Role / Device Role / Timing Role: Placed differentially across A/B bus lines to suppress ±157 V clamped transients (8/20 µs) without polarity biasing. Use Value: Enables robust communication up to 1 Mbps under IEC 61000-4-4 level 4 (4 kV) without signal distortion or latch-up. |
| Telecom Line Card Surge Protection | Automotive Body Control Module (BCM) Power Input |
Use Scenario: Front-end protection on POTS or xDSL line cards where AC coupling requires symmetrical surge suppression. IC Role / Device Role / Timing Role: Bidirectional clamping between tip/ring lines with 68 V stand-off to preserve DC bias while shunting >30 kV ESD events. Use Value: Maintains signal integrity over 100 kHz–30 MHz bandwidth (CJ ≈ 100 pF at 1 V) and survives repeated 30 kV discharges. | Use Scenario: 12 V battery rail protection in BCMs subjected to ISO 7637-2 pulse 1/2a/5a and ESD per ISO 10605. IC Role / Device Role / Timing Role: Mounted directly at connector entry point to clamp transients to ≤121 V before reaching LDOs and microcontrollers. Use Value: Supports 175 °C ambient operation in engine bay enclosures and handles 5000 W surges without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ68CA | Lower peak power (600 W), smaller SMB package, higher clamping (110 V @ 5.5 A) | Targeted at board-level signal line protection, not primary power rail clamping | Select when space-constrained layouts require SMT mounting and surge energy is ≤600 W |
| 1.5KE68CA | Higher leakage (10 µA), TO-204AA (DO-41) package, same 68 V VRM, clamping 118 V @ 42.5 A | Legacy through-hole design; less thermally robust at Tj > 150 °C | Choose for cost-sensitive legacy designs where R6 mechanical robustness and 175 °C rating are not required |
Compared with SMBJ68CA and 1.5KE68CA, BZW50-68B offers 8.3× higher peak power, superior high-temperature stability (175 °C vs. 150 °C), and lower leakage - making it optimal for primary-side AC/DC and high-reliability industrial power rails.
Availability
BZW50-68B is available at Aetrix Electronics and suitable for AC/DC power supply input protection, industrial fieldbus interface protection, telecom line card surge protection requiring stable component supply and long-term lifecycle support.
Supply support for BZW50-68B 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, specializing in power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.
The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for primary-side surge suppression in mains-connected equipment where reliability under sustained thermal stress and multi-kilowatt transient energy is mandatory.
FAQ
What is the difference between BZW50-68B and BZW50-68?
BZW50-68B is bidirectional, providing symmetrical clamping for AC signals or differential lines, while BZW50-68 is unidirectional with a cathode band marking and only clamps in one polarity. Both share identical VRM (68 V), VBR (75.6 V min), and PPP (5000 W), but BZW50-68B has no polarity marking and conducts during both positive and negative transients.
Can BZW50-68B be used in parallel for higher surge current handling?
No - paralleling TVS diodes without matched VBR and dynamic resistance causes current imbalance and premature failure. ST does not recommend parallel use. For higher current, select a single higher-rated device like BZW50-82B (145 V clamping at 34 A) or verify layout-based current sharing with derated margins.
What is the thermal resistance (Rth(j-a)) of BZW50-68B on a standard FR4 PCB?
On a 1 cm² copper pad per lead (2 cm² total), Rth(j-a) is approximately 40 °C/W. With 5 cm² total copper area, it drops to ~25 °C/W. Derating curves in DS0662 show 5000 W pulse capability falls to ~3700 W at Tj = 175 °C - confirming thermal design must prioritize copper area and airflow in high-ambient applications.
Does BZW50-68B meet UL 497B for telecom surge protection?
Yes - BZW50-68B carries UL 497B file number QVGQ2.E136224, certifying compliance for primary and secondary circuit protection in telecommunications equipment. This validates its use in POTS, xDSL, and Ethernet line cards meeting UL 60950-1 and UL 62368-1 requirements.
BZW50-68B 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 68V
- Voltage - Breakdown (Min):
- 75.6V
- Voltage - Clamping (Max) @ Ipp:
- 157V
- Current - Peak Pulse (10/1000µs):
- 382A (8/20µs)
- Power - Peak Pulse:
- 5000W (5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 1500pF @ 1MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- R-6
BZW50-68B FAQ
1.How can I place an order for BZW50-68B through Aetrix?
Please submit a Request for Quotation (RFQ) for BZW50-68B 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 BZW50-68B reliable?
The price and inventory of BZW50-68B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZW50-68B is usually 5 days.
3.What payment methods are accepted for BZW50-68B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZW50-68B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZW50-68B?
BZW50-68B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZW50-68B 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 BZW50-68B?
For technical support, including BZW50-68B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZW50-68B requirements.
6.How does Aetrix verify that BZW50-68B is sourced from the original manufacturer or authorized distributors?
All BZW50-68B 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 BZW50-68B meets industry standards.
7.What is the process for return or replacement of BZW50-68B?
All BZW50-68B units undergo pre-shipment inspection (PSI). If there is an issue with BZW50-68B, 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 BZW50-68B part is unused and in its original packaging.
Return procedure for BZW50-68B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZW50-68B Tags
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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