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Nexperia USA Inc. BZX84-B18,235
- Part No.:
- BZX84-B18,235
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BZX84-B18,235.pdf
- Description:
- DIODE ZENER 18V 250MW TO236AB
- Quantity:
- Payment:
- Shipping:
Inventory:8,269
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Product details
Overview
BZX84-B18,235 from Nexperia is a ±2 % tolerance Zener voltage regulator diode in SOT23 (TO-236AB) package, rated for 18 V nominal breakdown voltage at 5 mA test current, 250 mW total power dissipation, and 150 °C maximum junction temperature - used for precision low-power voltage reference and overvoltage protection in DC power rails of industrial sensor interfaces and microcontroller I/O conditioning circuits.
For engineers reviewing the BZX84-B18,235 datasheet, BZX84-B18,235 pinout, BZX84-B18,235 application, or BZX84-B18,235 equivalent, key selection criteria include Zener voltage tolerance (±2 %), differential resistance (≤225 Ω at IZ = 5 mA), thermal resistance (330 K/W to solder point), and non-repetitive surge capability (1.5 A peak reverse current).
Technical Context
This discrete Zener diode operates in reverse-biased breakdown mode to maintain stable voltage across its terminals under varying load or input conditions. Its regulation accuracy depends on specified test current (IZ = 5 mA), temperature coefficient (+12.6 mV/K), and low dynamic impedance (225 Ω max).
Designed for surface-mount use on FR4 PCBs with standard SOT23 footprint, it relies on thermal conduction through the cathode tab (Rth(j–sp) = 330 K/W) rather than ambient convection (Rth(j–a) = 500 K/W), making PCB copper area critical for sustained power handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 17.6 V to 18.4 V at IZ = 5 mA - defines regulated output voltage window under nominal bias |
| Differential Resistance rdif | ≤225 Ω at IZ = 5 mA - determines output voltage deviation under load current changes |
| Reverse Current IR | ≤0.05 μA at VR = 14.4 V - ensures minimal leakage below regulation threshold |
| Power Dissipation Ptot | 250 mW at Tamb ≤ 25 °C - sets maximum continuous DC power in standard PCB mounting |
| Non-repetitive Peak Current IZSM | 1.5 A for tp = 100 μs - supports transient overvoltage clamping without failure |
| Temperature Coefficient SZ | +12.6 mV/K at IZ = 5 mA - quantifies voltage drift per degree Celsius rise in junction temperature |
| Junction Temperature Tj | −55 °C to +150 °C - defines operational thermal envelope for reliability and lifetime |
Pinout & Package
Package: SOT23 (TO-236AB), 3-lead surface-mount plastic package with 1.9 mm × 1.1 mm body, 0.9 mm height, and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (A) | Forward-biased terminal; connected to lower-potential side in Zener regulation configuration |
| 2 | Not Connected (n.c.) | Internal die pad with no electrical connection - must remain unconnected on PCB |
| 3 | Cathode (K) | Reverse-biased terminal; connected to higher-potential side and serves as primary thermal path to PCB |
Key Features
| Feature | Design Value |
|---|---|
| ±2 % Zener voltage tolerance | Enables tighter regulation than ±5 % variants (BZX84-C18), reducing need for post-regulation trimming |
| 250 mW total power rating | Supports continuous operation in space-constrained 3.3 V/5 V rail monitoring without heatsinking |
| 1.5 A non-repetitive surge current | Clamps ESD transients (IEC 61000-4-2 Level 4) without degradation when placed at I/O entry points |
| SOT23 package with thermal cathode tab | Provides 330 K/W junction-to-solder-point thermal resistance - improves power handling vs. ambient-limited designs |
| Low 0.05 μA reverse leakage at 14.4 V | Minimizes standby current in battery-powered sensor nodes where quiescent power is critical |
Applications
| Industrial Sensor Signal Conditioning | Microcontroller I/O Protection |
|---|---|
Use Scenario: Stabilizing reference voltage for analog front-end circuitry in 4–20 mA loop-powered temperature transmitters. IC Role / Device Role / Timing Role: Zener diode provides fixed 18 V rail for op-amp biasing and ADC reference scaling. Use Value: ±2 % tolerance ensures <±0.36 V error in 18 V reference, enabling sub-0.5 % full-scale measurement accuracy. |
Use Scenario: Clamping GPIO pins against voltage spikes induced by relay coil back-EMF in PLC digital output modules. IC Role / Device Role / Timing Role: Reverse-connected Zener shunts transient energy to ground before MCU input structure exceeds absolute maximum ratings. Use Value: 1.5 A peak surge rating handles 100 μs inductive kick events without parametric shift or failure. |
| DC Power Rail Monitoring | Low-Power Battery Voltage Regulation |
Use Scenario: Detecting undervoltage condition in 24 V industrial control supply using comparator with Zener-derived threshold. IC Role / Device Role / Timing Role: Acts as precision voltage reference for comparator hysteresis network. Use Value: +12.6 mV/K temperature coefficient allows predictable threshold drift compensation in wide-temperature environments. |
Use Scenario: Regulating charging voltage for LiFePO₄ cells in portable diagnostic equipment powered by 20 V nominal solar input. IC Role / Device Role / Timing Role: Shunt regulator maintains constant 18 V across series-connected cell stack during float phase. Use Value: 225 Ω differential resistance limits output voltage variation to <±22.5 mV per ±1 mA load change, preserving charge termination accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C18,215 | ±5 % tolerance (16.2–19.8 V), higher IR (≤0.05 μA same), identical package and Ptot | Acceptable where cost sensitivity outweighs regulation precision; unsuitable for <1 % reference stability | Select when budget constraints dominate and system-level calibration compensates for wider VZ spread |
| MMSZ5245B-7-F | ±5 % tolerance, 18 V nominal, SOD-123 package, 500 mW Ptot, Rth(j–a) = 300 K/W | Higher power rating but larger footprint; better thermal performance on minimal copper, less suitable for ultra-dense layouts | Choose when board space permits larger package and >250 mW continuous dissipation is required |
Compared with BZX84-B18,235, the BZX84-C18,215 trades regulation accuracy for cost, while MMSZ5245B-7-F offers higher power handling at the expense of PCB area - making the BZX84-B18,235 optimal for compact, precision 18 V shunt regulation in industrial edge nodes.
Availability
BZX84-B18,235 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, microcontroller I/O protection, and DC power rail monitoring requiring stable component supply, consistent parametric binning, and long-term production continuity.
Supply support for BZX84-B18,235 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 semiconductor expert focused on high-volume, high-reliability logic, discrete, and MOSFET devices, headquartered in Nijmegen, Netherlands.
The BZX84 series belongs to Nexperia's precision Zener regulator portfolio, engineered specifically for low-power voltage reference and overvoltage protection in space-constrained industrial and consumer electronics.
FAQ
What is the maximum continuous forward current for BZX84-B18,235?
The BZX84-B18,235 is not intended for forward conduction; its absolute maximum forward current is 200 mA per datasheet limiting values, but forward operation exceeds design intent and risks parametric shift. It must be operated in reverse-biased Zener mode only.
Can BZX84-B18,235 replace BZX84-A18 in existing designs?
No - BZX84-A18 has ±1 % tolerance (17.82–18.18 V), while BZX84-B18,235 has ±2 % (17.6–18.4 V). Substituting introduces up to ±0.3 V additional voltage uncertainty, potentially violating tight reference or protection thresholds in calibrated systems.
How does ambient temperature affect Zener voltage stability?
Ambient temperature impacts BZX84-B18,235 indirectly via junction heating: at 150 °C Tj, the +12.6 mV/K coefficient causes ~1.26 V increase over 25 °C baseline. PCB copper area and airflow determine actual Tj rise under 250 mW load.
Is BZX84-B18,235 qualified for automotive applications?
No - per Nexperia's Rev. 7 datasheet revision history, the BZX84 series was explicitly changed to non-automotive qualification in 2023. Automotive-grade alternatives (e.g., BZX84-Q series) require separate part numbers and qualification documentation.
BZX84-B18,235 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX84
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±2%
- Power - Max:
- 250 mW
- Impedance (Max) (Zzt):
- 45 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 12.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BZX84-B18,235 FAQ
1.How can I place an order for BZX84-B18,235 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84-B18,235 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 BZX84-B18,235 reliable?
The price and inventory of BZX84-B18,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84-B18,235 is usually 5 days.
3.What payment methods are accepted for BZX84-B18,235?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84-B18,235 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84-B18,235?
BZX84-B18,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84-B18,235 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 BZX84-B18,235?
For technical support, including BZX84-B18,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84-B18,235 requirements.
6.How does Aetrix verify that BZX84-B18,235 is sourced from the original manufacturer or authorized distributors?
All BZX84-B18,235 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 BZX84-B18,235 meets industry standards.
7.What is the process for return or replacement of BZX84-B18,235?
All BZX84-B18,235 units undergo pre-shipment inspection (PSI). If there is an issue with BZX84-B18,235, 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 BZX84-B18,235 part is unused and in its original packaging.
Return procedure for BZX84-B18,235:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84-B18,235 Tags
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MMBZ5240B-7-F
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Diodes Incorporated
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onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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SMAZ12-13-F
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