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onsemi BZX79C22
- Part No.:
- BZX79C22
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
BZX79C22.pdf
- Description:
- DIODE ZENER 22V 500MW DO35
- Quantity:
- Payment:
- Shipping:
Inventory:2,251
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Product details
Overview
BZX79C22 from ON Semiconductor is a 22 V, 5% tolerance Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 55 Ω dynamic impedance at 5 mA test current and 0.05 μA leakage current at 16.8 V reverse voltage. It provides precise voltage regulation in low-power reference and protection circuits.
For engineers reviewing the BZX79C22 datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance (±5%), thermal coefficient (+16.4 mV/°C), junction capacitance (34 pF at 0 V), maximum leakage current, and DO-35 mechanical compatibility in space-constrained analog designs.
Technical Context
The BZX79C22 operates as a silicon planar epitaxial Zener diode optimized for stable voltage reference and overvoltage clamping. Its 22 V nominal breakdown voltage is specified at 5 mA test current, with a positive temperature coefficient of +16.4 mV/°C and 55 Ω dynamic impedance measured under same conditions.
Designed for operation within -65°C to +200°C ambient range, it features 0.05 μA maximum leakage at VR = 16.8 V and forward voltage ≤1.5 V at IF = 100 mA. The DO-35 package uses axial leads with cathode band marking and requires 3/8″ lead length for full 500 mW rating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 20.8 V min / 23.3 V max at IZ = 5 mA - defines regulated output range under standard test conditions |
| Tolerance | ±5% - ensures predictable voltage accuracy across production lots without trimming |
| Power Dissipation (PD) | 500 mW @ TL ≤ 75°C - sets maximum continuous thermal load in lead-mounted configuration |
| Dynamic Impedance (ZZ) | 55 Ω max @ IZ = 5 mA - determines regulation stiffness and output voltage variation under load changes |
| Leakage Current (IR) | 0.05 μA max @ VR = 16.8 V - critical for low-current bias networks and high-impedance sensing nodes |
| Junction Capacitance (CJ) | 34 pF @ VR = 0 V, f = 1 MHz - impacts high-frequency noise filtering and AC coupling performance |
| Temp. Coefficient (TC) | +16.4 mV/°C - quantifies voltage drift with ambient temperature, enabling thermal compensation design |
Pinout & Package
DO-35 glass axial-leaded package with cathode indicated by color band; no active pinout beyond anode/cathode polarity - bidirectional terminal function determined solely by DC bias direction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connects to lower potential side during forward bias; carries 100 mA max forward current |
| Cathode | Zener breakdown terminal | Marked with color band; connects to higher potential side during reverse-bias regulation |
Key Features
| Feature | Design Value |
|---|---|
| Stable Zener voltage reference | 22 V ±5% with <55 Ω dynamic impedance enables repeatable analog voltage setting in feedback loops |
| Low leakage current | 0.05 μA max at 16.8 V supports high-impedance biasing in precision op-amp and sensor circuits |
| Controlled temperature coefficient | +16.4 mV/°C allows predictable drift modeling for compensated reference designs |
| DO-35 glass package | Hermetically sealed axial construction ensures long-term stability and moisture resistance in industrial environments |
Applications
| Power Supply Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Low-cost linear regulator feedback node requiring stable 22 V reference. IC Role / Device Role / Timing Role: Zener diode acting as shunt voltage reference in TL431 or discrete op-amp feedback path. Use Value: Delivers 22 V ±5% regulation with <55 Ω impedance, minimizing output error across line/load variations. | Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 22 V. IC Role / Device Role / Timing Role: Reverse-biased clamping element diverting excess energy to ground before damage occurs. Use Value: Activates at 20.8–23.3 V range with 0.05 μA leakage, preserving signal integrity during normal operation. |
| Sensor Bias Network | Analog Signal Conditioning |
Use Scenario: Providing excitation voltage to resistive temperature detectors (RTDs) in industrial transmitters. IC Role / Device Role / Timing Role: Precision voltage source establishing known bias point for ratiometric measurement. Use Value: Stable 22 V reference with +16.4 mV/°C TC enables software-based thermal drift correction. | Use Scenario: Level-shifting audio or instrumentation signals to match ADC input ranges. IC Role / Device Role / Timing Role: Clamping diode limiting signal swing to prevent ADC saturation or amplifier rail-to-rail overload. Use Value: 34 pF junction capacitance minimizes high-frequency attenuation while maintaining fast response to transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4748A | 22 V ±5%, 1 W rating, DO-41 package, 50 Ω ZZ, +16 mV/°C TC | Higher power handling but larger footprint; requires PCB layout change | Select when >500 mW dissipation or improved thermal margin is required |
| MMSZ4696 | 22 V ±5%, 500 mW, SOD-123 surface-mount package, 55 Ω ZZ, +16.5 mV/°C TC | Same electrical specs but different mounting method; not drop-in compatible | Choose for automated assembly or space-constrained PCBs where through-hole is impractical |
Compared with BZX79C22, the 1N4748A offers higher power capacity in a larger DO-41 case, while MMSZ4696 delivers identical regulation performance in a compact SMD form - both require mechanical redesign but preserve core voltage reference functionality.
Availability
BZX79C22 is available at Aetrix Electronics and suitable for power supply reference, overvoltage clamp, and sensor bias network applications requiring stable component supply and long-term parametric consistency.
Supply support for BZX79C22 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
ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient electronics, with leadership in power management, analog, sensors, and logic devices.
The BZX79C series is part of ON Semiconductor's legacy Zener diode portfolio designed for general-purpose voltage regulation, reference, and protection in cost-sensitive industrial, consumer, and automotive auxiliary systems.
FAQ
What is the nominal Zener voltage of the BZX79C22?
The BZX79C22 has a nominal Zener voltage of 22 V, with a guaranteed range of 20.8 V to 23.3 V at 5 mA test current and ±5% tolerance. This specification is measured under thermal equilibrium at lead temperature of 30°C ±1°C with 3/8″ lead length, per ON Semiconductor datasheet Rev. 3. The BZX79C22 maintains this voltage regulation behavior across its operating temperature range.
What is the maximum power dissipation rating for the BZX79C22?
The BZX79C22 is rated for 500 mW power dissipation at lead temperature (TL) ≤ 75°C with 3/8″ lead length. Above 75°C, it derates linearly at 4.0 mW/°C. This rating assumes proper heat sinking via leads and applies only when mounted per specified mechanical conditions - exceeding it risks irreversible junction damage. The BZX79C22 must be operated within this limit to ensure long-term reliability.
What is the dynamic impedance of the BZX79C22 and why does it matter?
The BZX79C22 has a maximum dynamic impedance (ZZ) of 55 Ω at IZ = 5 mA. This value quantifies how much the Zener voltage changes with small variations in current - lower ZZ means tighter regulation. In practice, this allows the BZX79C22 to maintain stable reference voltage in feedback networks despite load fluctuations, making it suitable for precision analog circuits where voltage stability is critical.
How is polarity marked on the BZX79C22 DO-35 package?
The BZX79C22 uses a cathode band - a single colored stripe near one end of the DO-35 glass body - to indicate the cathode terminal. The unmarked end is the anode. This marking follows JEDEC standards and is visible under standard visual inspection. When installed in circuit, the cathode must connect to the higher-potential node for reverse-bias Zener operation. The BZX79C22's polarity marking is consistent across all BZX79C-series variants.
What is the leakage current specification for the BZX79C22?
The BZX79C22 specifies a maximum leakage current (IR) of 0.05 μA at reverse voltage (VR) = 16.8 V and TA = 25°C. This ultra-low leakage ensures minimal current draw in high-impedance bias networks and prevents signal degradation in sensitive analog front-ends. The BZX79C22 achieves this performance through controlled silicon doping and passivation, making it suitable for battery-powered and precision measurement applications.
BZX79C22 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 22 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 55 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 15.4 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
BZX79C22 FAQ
1.How can I place an order for BZX79C22 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX79C22 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 BZX79C22 reliable?
The price and inventory of BZX79C22 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79C22 is usually 5 days.
3.What payment methods are accepted for BZX79C22?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79C22 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX79C22?
BZX79C22 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX79C22 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 BZX79C22?
For technical support, including BZX79C22 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79C22 requirements.
6.How does Aetrix verify that BZX79C22 is sourced from the original manufacturer or authorized distributors?
All BZX79C22 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 BZX79C22 meets industry standards.
7.What is the process for return or replacement of BZX79C22?
All BZX79C22 units undergo pre-shipment inspection (PSI). If there is an issue with BZX79C22, 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 BZX79C22 part is unused and in its original packaging.
Return procedure for BZX79C22:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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