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onsemi BZX79C47
- Part No.:
- BZX79C47
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79C47.pdf
- Description:
- DIODE ZENER 47V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:30,000
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Product details
Overview
BZX79C47 from Fairchild Semiconductor is a 47 V ±5% tolerance silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 170 Ω dynamic impedance at 2 mA test current and 0.05 μA maximum leakage at 35.7 V reverse voltage. It serves as a precision voltage reference or overvoltage clamp in low-power analog circuits.
For engineers reviewing the BZX79C47 datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal coefficient (−3.5 mV/°C), junction capacitance (19 pF at 0 V), forward voltage (≤1.5 V @ 100 mA), and DO-35 mechanical compatibility in space-constrained PCB layouts.
Technical Context
The BZX79C47 operates as a two-terminal voltage-regulating device relying on controlled reverse-biased avalanche breakdown. Its −3.5 mV/°C temperature coefficient ensures predictable drift across −65°C to +200°C operating range, and its 170 Ω dynamic impedance at IZ = 2 mA supports stable regulation under light-load conditions.
Designed for DC voltage reference and transient suppression, it exhibits 0.05 μA leakage at VR = 35.7 V and 19 pF junction capacitance at 0 V, making it suitable for low-frequency stabilization where capacitive loading must be minimized.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 44 V min / 50 V max at IZ = 2 mA - defines usable clamping/reference window under nominal bias |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous thermal load without derating |
| Dynamic Impedance (ZZ) | 170 Ω max @ IZ = 2 mA - determines output voltage variation under small-signal current changes |
| Leakage Current (IR) | 0.05 μA max @ VR = 35.7 V - ensures minimal parasitic current in high-impedance bias networks |
| Junction Capacitance (CJ) | 19 pF @ VR = 0 V, f = 1 MHz - limits high-frequency noise coupling and AC bypass effectiveness |
| Temperature Coefficient (TC) | −3.5 mV/°C - quantifies voltage drift per degree Celsius, critical for temperature-stable references |
| Forward Voltage (VF) | ≤1.5 V @ IF = 100 mA - enables use as polarity-sensitive protection diode in series configurations |
Pinout & Package
DO-35 glass axial package with cathode indicated by color band; two-terminal device requiring no external biasing circuitry.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; connected to lower potential in Zener operation | Accepts forward current up to 100 mA; referenced to ground or common rail in shunt regulator topology |
| Cathode | Current exit terminal in forward bias; higher-potential terminal during Zener breakdown | Connected to regulated node; color band identifies this terminal for correct PCB orientation and polarity assurance |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables consistent voltage setting across production lots without individual calibration |
| −3.5 mV/°C temperature coefficient | Supports stable reference performance in industrial environments with ambient swings up to 100°C |
| DO-35 glass package | Provides hermetic sealing and thermal stability for long-term reliability in non-hermetic assemblies |
| 500 mW power rating | Allows direct replacement of legacy ½-Watt Zeners without heatsinking in low-current applications |
| 0.05 μA max leakage at 35.7 V | Minimizes error in high-resistance divider networks used for microcontroller ADC reference scaling |
Applications
| Industrial Sensor Signal Conditioning | Microcontroller Power Rail Clamp |
|---|---|
Use Scenario: Stabilizing excitation voltage for resistive bridge sensors in PLC analog input modules. IC Role / Device Role / Timing Role: Shunt voltage reference providing fixed 47 V bias to Wheatstone bridge. Use Value: Tight 5% tolerance and low TC ensure <±0.5% full-scale error contribution over −40°C to +85°C operating range. |
Use Scenario: Protecting 3.3 V or 5 V MCU I/O pins against ESD-induced transients exceeding supply rails. IC Role / Device Role / Timing Role: Low-capacitance (19 pF) transient voltage suppressor clamping to safe levels. Use Value: Sub-μA leakage avoids loading weak pull-up networks; fast avalanche response limits voltage overshoot to <55 V. |
| Programmable Power Supply Feedback | Legacy Equipment Voltage Calibration |
Use Scenario: Setting precise output voltage in adjustable linear regulators using resistor-divider feedback. IC Role / Device Role / Timing Role: Precision Zener reference replacing TL431 in cost-sensitive 47 V output designs. Use Value: 170 Ω ZZ enables stable loop compensation with standard op-amp error amplifiers and minimal phase shift. |
Use Scenario: Replacing obsolete 47 V Zeners in field-service calibration of analog test equipment. IC Role / Device Role / Timing Role: Drop-in mechanical and electrical replacement for BZX55C47 and similar DO-35 parts. Use Value: Identical DO-35 footprint and 44–50 V VZ range ensures zero PCB rework during repair or upgrade cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ON Semiconductor MMBZ5256B | Same 47 V nominal VZ, but SOD-123 surface-mount package; 100 Ω ZZ; 0.1 μA IR @ 35.7 V | Requires PCB redesign for SMT assembly; better suited for automated high-volume production | Select when board space is constrained and reflow capability exists; not drop-in for through-hole DO-35 layouts |
| Vishay BZX55-C47 | Identical DO-35 package and 44–50 V VZ range; 180 Ω ZZ; −3.5 mV/°C TC; same 500 mW rating | No layout or schematic change required; minor variance in leakage (0.1 μA vs. 0.05 μA) | Preferred for direct replacement in legacy through-hole systems where sourcing flexibility is needed |
Compared with MMBZ5256B and BZX55-C47, the BZX79C47 offers the lowest leakage (0.05 μA) and matches BZX55-C47's mechanical fit while differing in manufacturer-specific process optimization-making it ideal for repair, calibration, and low-leakage analog reference roles.
Availability
BZX79C47 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, microcontroller power rail clamp, and programmable power supply feedback requiring stable component supply and long-lifecycle support.
Supply support for BZX79C47 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016; known for robust, industry-standard diodes and MOSFETs.
The BZX79C47 belongs to Fairchild's legacy BZX79C Zener diode family, designed specifically for general-purpose voltage regulation and transient suppression in cost-sensitive industrial and consumer electronics.
FAQ
What is the Zener voltage tolerance of the BZX79C47?
The BZX79C47 has a guaranteed Zener voltage range of 44 V to 50 V at 2 mA test current, corresponding to a ±5% tolerance. This specification is measured under thermal equilibrium at lead temperature of 30°C ±1°C with 3/8" lead length, ensuring repeatability in production testing and system-level validation of the BZX79C47.
Does the BZX79C47 have a specified temperature coefficient?
Yes, the BZX79C47 has a temperature coefficient of −3.5 mV/°C, meaning its Zener voltage decreases by 3.5 mV per degree Celsius rise in junction temperature. This value is confirmed in the Electrical Characteristics table of the Fairchild datasheet and applies across the full −65°C to +200°C operating range of the BZX79C47.
What is the maximum leakage current for the BZX79C47?
The BZX79C47 specifies a maximum leakage current of 0.05 μA at a reverse voltage of 35.7 V. This ultra-low leakage enables use in high-impedance voltage divider networks and precision reference circuits where parasitic current would otherwise introduce measurable error in the BZX79C47-based design.
Can the BZX79C47 be used in surface-mount applications?
No-the BZX79C47 is packaged exclusively in the through-hole DO-35 glass axial case and is not compatible with surface-mount assembly processes. For SMT equivalents, consider the ON Semiconductor MMBZ5256B or Diodes Inc. BZT52-B47, both of which require PCB layout changes and are not direct replacements for the BZX79C47.
What is the forward voltage rating of the BZX79C47?
The BZX79C47 has a maximum forward voltage of 1.5 V at 100 mA forward current. This parameter confirms its suitability as a polarity-aware protection element in series configurations and validates compatibility with standard silicon diode drive circuits when used in forward conduction mode alongside its primary Zener function.
BZX79C47 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 47 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 170 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 32.9 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 100 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-35
BZX79C47 FAQ
1.How can I place an order for BZX79C47 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79C47 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 BZX79C47 reliable?
The price and inventory of BZX79C47 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79C47 is usually 5 days.
3.What payment methods are accepted for BZX79C47?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79C47 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79C47?
BZX79C47 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79C47 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 BZX79C47?
For technical support, including BZX79C47 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79C47 requirements.
6.How does Aetrix verify that BZX79C47 is sourced from the original manufacturer or authorized distributors?
All BZX79C47 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 BZX79C47 meets industry standards.
7.What is the process for return or replacement of BZX79C47?
All BZX79C47 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79C47, 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 BZX79C47 part is unused and in its original packaging.
Return procedure for BZX79C47:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX79C47 Tags
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