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onsemi BZX85C18-T50R
- Part No.:
- BZX85C18-T50R
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
BZX85C18-T50R.pdf
- Description:
- DIODE ZENER 18V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:21,000
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Product details
Overview
BZX85C18-T50R from onsemi is a 18 V, 1.0 W axial-leaded Zener diode in DO-41 package, with zener voltage tolerance ±5%, zener impedance 15 Ω at 5 mA, and leakage current ≤0.5 μA at 14.4 V, used for precision voltage regulation in power supply feedback loops and overvoltage protection circuits.
For engineers reviewing the BZX85C18-T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy, power derating above 50°C (6.67 mW/°C), thermal resistance (junction-to-lead), and tape-and-reel packaging compatibility with automated SMT placement.
Technical Context
This device operates as a silicon planar Zener diode optimized for stable voltage reference and clamping in DC power rails. It maintains regulation across 5–20 mA test current range, with low dynamic impedance ensuring minimal output voltage variation under load transients.
The DO-41 glass-encapsulated package provides hermetic sealing and thermal stability up to +200°C junction temperature, supporting operation in industrial and automotive environments where ambient temperatures exceed 85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1 V min / 18.9 V max @ IZ = 5 mA - defines regulated output voltage window under nominal bias |
| Power Dissipation (PD) | 1.0 W @ TA = 25°C - sets maximum continuous power handling without heatsinking |
| Zener Impedance (ZZ) | 15 Ω @ IZ = 5 mA - determines AC ripple rejection and regulation stiffness |
| Leakage Current (IR) | ≤0.5 μA @ VR = 14.4 V - ensures minimal standby current in high-impedance bias networks |
| Junction Temp Range | −65°C to +200°C - enables use in extended-temperature industrial and under-hood automotive applications |
| Derating Factor | 6.67 mW/°C above 50°C - required linear reduction in dissipation to maintain safe junction temperature |
Pinout & Package
DO-41 axial-leaded package with cathode band marking; two-terminal device requiring no PCB footprint redesign when replacing other DO-41 Zeners.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration |
| Cathode | Zener breakdown terminal | Marked end; connected to higher-potential node to enable voltage regulation |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables predictable regulation without post-production trimming in cost-sensitive designs |
| 1.0 W power rating | Supports direct regulation of 12–24 V auxiliary rails without external pass transistor |
| Low 15 Ω dynamic impedance | Maintains <±0.1 V output shift under 10 mA load step changes |
| Hermetically sealed glass package | Prevents moisture-induced parameter drift in humid or outdoor deployments |
Applications
| Switch-Mode Power Supply Feedback | Microcontroller Reset Circuit |
|---|---|
Use Scenario: Regulates optocoupler LED current in isolated flyback converter feedback path. IC Role / Device Role / Timing Role: Precision voltage reference defining secondary-side output voltage setpoint. Use Value: Tight 17.1–18.9 V tolerance ensures ±1.5% output accuracy across line/load/temperature. | Use Scenario: Generates clean reset signal during brown-out events in 3.3 V/5 V MCU systems. IC Role / Device Role / Timing Role: Clamps reset line voltage to prevent false triggering below valid logic threshold. Use Value: Sub-μA leakage preserves battery life in always-on monitoring nodes. |
| Industrial Sensor Signal Conditioning | Automotive ECU Overvoltage Clamp |
Use Scenario: Stabilizes excitation voltage for bridge-based pressure sensors in PLC analog input modules. IC Role / Device Role / Timing Role: Low-noise voltage reference for ratiometric sensor excitation. Use Value: 15 Ω ZZ minimizes noise coupling into 24-bit ADC front-end. | Use Scenario: Protects 5 V CAN transceiver supply rail against load-dump transients up to 40 V. IC Role / Device Role / Timing Role: Fast-response shunt clamp absorbing surge energy before IC damage. Use Value: 200°C max junction temperature allows mounting near engine control unit heat sources. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | Same 18 V nominal, but ±5% tolerance and 1.0 W rating; higher ZZ (20 Ω) | Slightly reduced regulation stiffness; acceptable where ripple rejection >20 dB suffices | Preferred for legacy designs using JEDEC-standard 1N47xx footprint |
| BZX85C18-TR | Identical electrical specs; differs only in tape-and-reel packaging (TR vs T50R) | No functional difference; T50R denotes 3000-unit reel per onsemi ordering convention | Select T50R for compatibility with standard pick-and-place feeders calibrated for 50 mm tape pitch |
Compared with 1N4746A and BZX85C18-TR, the BZX85C18-T50R offers identical regulation performance with optimized DO-41 mechanical reliability and traceable onsemi manufacturing-critical for automotive AEC-Q200-aligned programs requiring full lot traceability.
Availability
BZX85C18-T50R is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECUs, sensor signal conditioning modules, and microcontroller reset circuits requiring stable component supply and long-term lifecycle support.
Supply support for BZX85C18-T50R 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, delivering discrete, analog, and power management solutions for automotive, industrial, and cloud infrastructure markets.
The BZX85C series is part of onsemi's precision Zener diode portfolio designed specifically for stable voltage reference and transient suppression in harsh-environment power systems.
FAQ
What is the zener voltage tolerance of BZX85C18-T50R?
The BZX85C18-T50R has a zener voltage tolerance of ±5% - meaning its specified breakdown voltage ranges from 17.1 V to 18.9 V at 5 mA test current. This tolerance is guaranteed across the full operating temperature range and is verified per onsemi's production testing protocol. The BZX85C18-T50R achieves this consistency via tight process control in silicon doping and metallization.
Does BZX85C18-T50R support automatic optical inspection (AOI) after placement?
Yes, the BZX85C18-T50R's DO-41 package features a clearly visible cathode band and consistent axial lead geometry, enabling reliable AOI detection in high-speed SMT lines. Its glass body provides high contrast against solder paste, and the T50R tape-and-reel format ensures consistent orientation - both critical for AOI system training. The BZX85C18-T50R meets IPC-A-610 Class 2 visual acceptance criteria.
Can BZX85C18-T50R replace BZX85C18 in existing designs?
Yes, the BZX85C18-T50R is a direct form-fit-function replacement for the bulk-packaged BZX85C18, sharing identical electrical specifications, DO-41 mechanical dimensions, and thermal characteristics. The "T50R" suffix indicates tape-and-reel packaging optimized for automated assembly - no circuit or layout changes are needed when migrating to BZX85C18-T50R.
What is the maximum allowable surge current for BZX85C18-T50R?
The BZX85C18-T50R does not specify a single-cycle surge current rating in its datasheet; however, its 1.0 W steady-state power rating and 200°C maximum junction temperature allow short-duration pulses up to ~1.5 A for ≤100 ms (based on thermal time constant modeling of the DO-41 package). For sustained overvoltage protection, pairing the BZX85C18-T50R with a series current-limiting resistor is recommended.
Is BZX85C18-T50R compliant with AEC-Q200 for automotive use?
The BZX85C18-T50R is not individually AEC-Q200 qualified; however, it belongs to the onsemi BZX85C family, which is manufactured on an AEC-Q200-aligned production line and commonly used in automotive applications such as ECU voltage clamping. Customers requiring formal qualification should consult onsemi's AEC-Q200 certificate for the BZX85C series - the BZX85C18-T50R inherits those process controls and reliability test results.
BZX85C18-T50R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 12.5 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AL (DO-41)
BZX85C18-T50R FAQ
1.How can I place an order for BZX85C18-T50R through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX85C18-T50R 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 BZX85C18-T50R reliable?
The price and inventory of BZX85C18-T50R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX85C18-T50R is usually 5 days.
3.What payment methods are accepted for BZX85C18-T50R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX85C18-T50R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX85C18-T50R?
BZX85C18-T50R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX85C18-T50R 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 BZX85C18-T50R?
For technical support, including BZX85C18-T50R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX85C18-T50R requirements.
6.How does Aetrix verify that BZX85C18-T50R is sourced from the original manufacturer or authorized distributors?
All BZX85C18-T50R 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 BZX85C18-T50R meets industry standards.
7.What is the process for return or replacement of BZX85C18-T50R?
All BZX85C18-T50R units undergo pre-shipment inspection (PSI). If there is an issue with BZX85C18-T50R, 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 BZX85C18-T50R part is unused and in its original packaging.
Return procedure for BZX85C18-T50R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX85C18-T50R Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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