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Nexperia USA Inc. BZX79-B68,143
- Part No.:
- BZX79-B68,143
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79-B68,143.pdf
- Description:
- DIODE ZENER 68V 400MW ALF2
- Quantity:
- Payment:
- Shipping:
Inventory:4,980
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Product details
Overview
BZX79-B68,143 from Nexperia is a ±2% tolerance Zener voltage regulator diode with nominal breakdown voltage of 68 V, total power dissipation up to 500 mW at Tamb = 50 °C, and differential resistance of 150 Ω (typ.) at IZ = 2 mA - used as a precision low-power voltage reference in analog sensor signal conditioning circuits.
For engineers reviewing the BZX79-B68,143 datasheet, BZX79-B68,143 pinout, BZX79-B68,143 application, or BZX79-B68,143 equivalent, key selection criteria include Zener voltage tolerance (±2%), thermal resistance (Rth j-a = 380 K/W), non-repetitive peak reverse power (40 W), and DO-35 package compatibility with through-hole PCB assembly.
Technical Context
This device operates as a two-terminal silicon Zener diode optimized for stable DC voltage regulation in low-current (<2 mA) bias conditions. Its temperature coefficient of +90 mV/K (typ. at IZ = 2 mA) ensures predictable positive drift above 6.2 V, enabling compensated reference designs when paired with negative-TC components.
The SOD27 (DO-35) hermetically sealed glass package supports axial lead mounting with cathode band marking, and its junction-to-ambient thermal resistance (380 K/W) defines safe continuous operation only below 400 mW at 50 °C ambient - requiring derating above that temperature per Fig.2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 66.6 V to 69.4 V at IZ = 2 mA - defines tight ±2% regulation window for reference stability. |
| Differential Resistance rdif | 150 Ω (max) at IZ = 2 mA - determines output impedance and load regulation error under varying current. |
| Temperature Coefficient SZ | +90 mV/K (typ.) - enables predictable positive voltage drift for temperature-compensated reference design. |
| Total Power Dissipation Ptot | 500 mW at Tamb = 50 °C - sets maximum continuous bias power before thermal runaway risk. |
| Non-repetitive Peak Power PZSM | 40 W for tp = 100 μs - supports transient overvoltage clamping in surge protection circuits. |
| Reverse Current IR | 50 nA max at VR = 0.7 × VZnom - ensures minimal leakage in high-impedance reference nodes. |
Pinout & Package
Hermetically sealed glass SOD27 (DO-35) axial-leaded package with cathode identified by a colored band. Leads are tinned copper-clad steel; body diameter 1.85 mm, length 4.25 mm, lead spacing 25.4 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-impedance sink during regulation | Connected to circuit ground or lower potential node; carries forward current up to 250 mA. |
| Cathode | Zener breakdown terminal / regulated output node | Marked with band; supplies stable 68 V reference when reverse-biased above VZ. |
Key Features
| Feature | Design Value |
|---|---|
| ±2% Zener voltage tolerance | Enables direct use in precision references without post-calibration trimming. |
| Hermetic glass SOD27 package | Provides long-term reliability and moisture resistance in industrial environments. |
| Low leakage (50 nA) | Maintains accuracy in high-impedance feedback networks and battery-powered sensors. |
| 40 W non-repetitive surge rating | Supports transient suppression in low-energy ESD or inductive kickback scenarios. |
Applications
| Industrial Sensor Reference | Power Supply Feedback |
|---|---|
|
Use Scenario: Providing stable 68 V reference for 4–20 mA transmitter loop calibration circuitry. IC Role / Device Role / Timing Role: Zener diode operating in reverse breakdown to fix reference voltage at ADC input stage. Use Value: ±2% tolerance eliminates need for external trimming resistors, reducing BOM count and calibration labor. |
Use Scenario: Setting overvoltage threshold in flyback converter feedback divider network. IC Role / Device Role / Timing Role: Precision voltage clamp defining shutdown trigger point for primary-side controller. Use Value: 150 Ω differential resistance minimizes error from divider current variation across line/load changes. |
| Medical Instrument Biasing | Test Equipment Calibration |
|
Use Scenario: Generating fixed bias for photodiode transimpedance amplifier in portable pulse oximeter. IC Role / Device Role / Timing Role: Low-leakage (50 nA) Zener supplying clean reference to op-amp bias network. Use Value: Sub-100 nA reverse current prevents signal offset drift in high-gain, low-noise analog front-end. |
Use Scenario: Serving as traceable voltage standard in handheld multimeter internal reference chain. IC Role / Device Role / Timing Role: Primary Zener element in cascaded reference stack for 68 V calibration point. Use Value: Hermetic DO-35 packaging ensures long-term parameter stability required for metrology-grade instruments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4744A | 68 V nominal, ±5% tolerance, 1 W power rating, DO-41 package | Higher power handling but looser tolerance; requires larger PCB footprint | Select when higher surge energy absorption is needed and ±5% regulation is acceptable. |
| BZX85C68 | 68 V nominal, ±5% tolerance, 1.3 W power rating, DO-41 package | Higher Ptot and different thermal profile; not hermetically sealed | Prefer for cost-sensitive industrial power supplies where long-term hermeticity is not critical. |
Compared with BZX79-B68,143, the 1N4744A offers higher surge robustness but sacrifices precision; the BZX85C68 trades hermetic reliability for higher continuous power - making the BZX79-B68,143 optimal for space-constrained, high-stability analog references.
Availability
BZX79-B68,143 is available at Aetrix Electronics and suitable for industrial sensor reference, power supply feedback, medical instrument biasing, and test equipment calibration requiring stable component supply across extended production lifecycles.
Supply support for BZX79-B68,143 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
Nexperia is a global leader in discrete, logic, and PowerMOS semiconductors, spun off from NXP in 2017 and focused on automotive, industrial, computing, and consumer markets.
The BZX79 series belongs to Nexperia's legacy Zener diode portfolio designed specifically for precision low-power voltage regulation and reference applications in space-constrained, high-reliability systems.
FAQ
What is the maximum continuous reverse current this diode can handle at 68 V?
The BZX79-B68,143 is not rated for continuous reverse current at full Zener voltage - it is designed for regulated bias current (typically 2 mA). Continuous operation at 68 V requires limiting current to ≤2 mA to stay within 400 mW dissipation at 50 °C ambient; exceeding this risks thermal runaway due to Rth j-a = 380 K/W.
Can this diode be used in surface-mount designs?
No - the BZX79-B68,143 uses an axial-leaded SOD27 (DO-35) glass package intended for through-hole mounting only. It lacks solder pads or terminations compatible with reflow or wave soldering processes. For SMT equivalents, consider Nexperia's BZX384-B68 (SOD-323) or BZX584C68 (SOT-23).
How does the +90 mV/K temperature coefficient affect circuit performance?
The +90 mV/K coefficient means output voltage increases ~6.1 V over a 68 °C rise (e.g., from 25 °C to 93 °C junction temperature). This must be compensated in precision references using negative-TC components (e.g., forward-biased diodes) or calibrated out in closed-loop systems.
Is the cathode band polarity consistent across all BZX79-B variants?
Yes - all BZX79-B series diodes, including BZX79-B68,143, mark the cathode with a single axial band near one lead end. The banded end connects to the higher-potential node in Zener regulation mode and must be oriented correctly in PCB layout to avoid forward conduction failure.
BZX79-B68,143 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 68 V
- Tolerance:
- ±2%
- Power - Max:
- 400 mW
- Impedance (Max) (Zzt):
- 240 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 47.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- ALF2
BZX79-B68,143 FAQ
1.How can I place an order for BZX79-B68,143 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79-B68,143 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 BZX79-B68,143 reliable?
The price and inventory of BZX79-B68,143 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79-B68,143 is usually 5 days.
3.What payment methods are accepted for BZX79-B68,143?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79-B68,143 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79-B68,143?
BZX79-B68,143 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79-B68,143 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 BZX79-B68,143?
For technical support, including BZX79-B68,143 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79-B68,143 requirements.
6.How does Aetrix verify that BZX79-B68,143 is sourced from the original manufacturer or authorized distributors?
All BZX79-B68,143 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 BZX79-B68,143 meets industry standards.
7.What is the process for return or replacement of BZX79-B68,143?
All BZX79-B68,143 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79-B68,143, 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 BZX79-B68,143 part is unused and in its original packaging.
Return procedure for BZX79-B68,143:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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