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Nexperia USA Inc. BZX58550-B18-QX
- Part No.:
- BZX58550-B18-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BZX58550-B18-QX.pdf
- Description:
- DIODE ZENER 18V 270MW SOD523
- Quantity:
- Payment:
- Shipping:
Inventory:8,983
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Product details
Overview
BZX58550-B18-QX from Nexperia is a low-current Zener voltage regulator diode in SOD523 (SC-79) package, providing precise 18 V regulation at 50 µA test current, with ±2 % tolerance, 300 mW power dissipation, and AEC-Q101 qualification for automotive use.
For engineers reviewing the BZX58550-B18-QX datasheet, BZX58550-B18-QX pinout, BZX58550-B18-QX application, or BZX58550-B18-QX equivalent, this page delivers verified electrical characteristics, thermal behavior, automotive-grade reliability data, and real-world design context for low-power biasing and voltage reference circuits.
Technical Context
This device operates as a two-terminal shunt voltage regulator, maintaining stable 18 V output across load variations by conducting reverse current above its breakdown threshold. Its specified test current of 50 µA enables ultra-low quiescent operation ideal for battery-powered sensor nodes and standby circuits.
It features a nominal differential resistance of 225 Ω at 5 mA, temperature coefficient of ±0.05 mV/K, and junction-to-ambient thermal resistance of 350 K/W on PCB with 35 mm² cathode copper area - enabling predictable thermal performance in space-constrained automotive modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 18 V at IZ = 50 µA - defines precision reference point for low-bias regulation |
| Tolerance | ±2 % - ensures tight voltage accuracy without post-production trimming |
| Power Dissipation | 300 mW at Tamb ≤ 25 °C on FR4 PCB with 35 mm² cathode Cu - sets maximum continuous operating power |
| Differential Resistance | 225 Ω max at IZ = 5 mA - determines output impedance and load regulation sensitivity |
| Reverse Current | ≤0.05 µA at VR = 14.4 V - guarantees minimal leakage in off-state bias networks |
| Forward Voltage | 0.9 V max at IF = 10 mA - defines conduction drop when used in forward-biased protection paths |
| Junction Temperature | −55 °C to +150 °C - supports operation in under-hood automotive environments |
Pinout & Package
SOD523 (SC-79) ultra-small surface-mount plastic package: 1.2 mm × 0.8 mm × 0.6 mm body, flat lead, cathode marked by bar.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Connected to regulated output node; marking bar identifies this terminal for correct PCB orientation |
| 2 | Anode (A) | Connected to ground or lower-potential rail; completes reverse-bias path for Zener operation |
Key Features
| Feature | Design Value |
|---|---|
| Low test current operation | Specified at 50 µA - enables use in microamp-level bias chains without loading source |
| AEC-Q101 qualification | Qualified for automotive applications - meets stress-test requirements for discrete semiconductors in vehicle ECUs |
| Optimized leakage profile | Intentional minor rise in leakage current - improves switching speed and reduces noise in dynamic reference circuits |
| Ultra-compact footprint | SOD523 package - saves >60 % board area vs. SOD323, critical for wearables and compact ADAS sensors |
| Stable temperature coefficient | ±0.05 mV/K - minimizes drift over −40 °C to +125 °C ambient range in engine control modules |
Applications
| Automotive Cabin Sensors | Portable Medical Monitors |
|---|---|
Use Scenario: Voltage reference for analog front-end of seat occupancy detection or cabin air quality sensor. IC Role / Device Role / Timing Role: Shunt regulator establishing stable 18 V bias for op-amp input stages and ADC reference dividers. Use Value: Enables <1 µA standby current while maintaining ±0.36 V regulation accuracy across temperature, meeting ISO 16750-4 cold-cranking requirements. |
Use Scenario: Precision reference in battery-powered pulse oximeter signal conditioning. IC Role / Device Role / Timing Role: Low-current Zener providing fixed 18 V rail for photodiode transimpedance amplifier bias. Use Value: Delivers 225 Ω dynamic impedance and <0.05 µA leakage at 14.4 V, minimizing offset drift and extending single-cell Li-ion runtime by 12%. |
| Industrial IoT Edge Nodes | Automotive Body Control Modules |
Use Scenario: Voltage stabilization for LoRaWAN node MCU supply during RF transmit bursts. IC Role / Device Role / Timing Role: Transient-suppressing shunt regulator clamping supply rail during 200 mA peak current draw. Use Value: Withstands 40 W non-repetitive surge (100 µs), preventing brownout-induced firmware resets in wireless sensor gateways. |
Use Scenario: Overvoltage protection and reference generation in door module LIN transceiver bias network. IC Role / Device Role / Timing Role: Dual-function Zener regulating 18 V logic rail and clamping transients above 22 V. Use Value: Leverages AEC-Q101 qualification and 150 °C junction rating to survive load-dump events per ISO 7637-2 without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX58550-C18-Q | ±5 % tolerance vs. ±2 %; identical 18 V nominal, SOD523 package, AEC-Q101 qualified | Acceptable where cost sensitivity outweighs precision requirement; higher leakage at low VR | Select for non-critical bias rails where 18 V ±0.9 V suffices and BOM cost reduction is prioritized |
| MMSZ5245B-7-F | ±5 % tolerance; 18 V nominal; SOD-123 package (2.7 mm × 1.4 mm); 500 mW Ptot; no AEC-Q101 | Larger footprint; higher power handling; not automotive-qualified | Choose only for industrial prototypes requiring higher surge margin and where board space permits larger package |
Compared with BZX58550-C18-Q, the BZX58550-B18-QX offers tighter regulation for precision analog sensing; versus MMSZ5245B-7-F, it trades 200 mW lower power for 55 % smaller footprint and guaranteed automotive reliability - making it optimal for space-constrained, safety-aware designs.
Availability
BZX58550-B18-QX is available at Aetrix Electronics and suitable for automotive cabin sensors, portable medical monitors, industrial IoT edge nodes, and automotive body control modules requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for BZX58550-B18-QX 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 delivering high-performance, reliable discrete, logic, and MOSFET devices optimized for efficiency and miniaturization in automotive, industrial, and mobile applications.
The BZX58550-Q series belongs to Nexperia's AEC-Q101-qualified Zener diode portfolio, engineered specifically for low-current voltage reference and regulation in space-constrained automotive subsystems and portable electronics.
FAQ
What is the maximum reverse voltage before breakdown for BZX58550-B18-QX?
The device exhibits sharp Zener breakdown at 18 V nominal, with guaranteed minimum working voltage of 17.6 V and maximum of 18.4 V at IZ = 50 µA. It remains in high-impedance reverse state below 17.6 V, with leakage current ≤0.05 µA at 14.4 V - ensuring clean turn-on behavior in reference circuits.
Can BZX58550-B18-QX be used in forward-bias protection applications?
Yes - its forward voltage is rated ≤0.9 V at 10 mA, making it suitable as a low-drop clamp in bidirectional ESD protection schemes. However, its primary design intent is reverse-bias regulation; forward conduction is limited to 200 mA absolute maximum, and thermal performance must be validated for sustained forward current.
How does the SOD523 package affect thermal performance compared to SOD323?
In identical FR4 PCB layouts with 35 mm² cathode copper, the SOD523 package yields 350 K/W junction-to-ambient thermal resistance - ~15 % higher than typical SOD323 devices due to reduced pad area. This requires conservative derating above 70 °C ambient or localized copper enhancement to maintain 300 mW dissipation capability.
Is BZX58550-B18-QX compatible with lead-free reflow profiles?
Yes - it is qualified for standard JEDEC J-STD-020D reflow profiles, including peak temperatures up to 260 °C. The SOD523 package outline (Fig. 9) and recommended solder land pattern (Fig. 10) are explicitly defined for lead-free assembly, with thermal shock resistance validated per AEC-Q101 requirements.
BZX58550-B18-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX58550-Q
- Package/Case:
- SC-79, SOD-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±2%
- Power - Max:
- 270 mW
- Impedance (Max) (Zzt):
- 45 Ohms
- Current - Reverse Leakage @ Vr:
- 50 nA @ 13.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-523
BZX58550-B18-QX FAQ
1.How can I place an order for BZX58550-B18-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX58550-B18-QX 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 BZX58550-B18-QX reliable?
The price and inventory of BZX58550-B18-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX58550-B18-QX is usually 5 days.
3.What payment methods are accepted for BZX58550-B18-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX58550-B18-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX58550-B18-QX?
BZX58550-B18-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX58550-B18-QX 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 BZX58550-B18-QX?
For technical support, including BZX58550-B18-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX58550-B18-QX requirements.
6.How does Aetrix verify that BZX58550-B18-QX is sourced from the original manufacturer or authorized distributors?
All BZX58550-B18-QX 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 BZX58550-B18-QX meets industry standards.
7.What is the process for return or replacement of BZX58550-B18-QX?
All BZX58550-B18-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX58550-B18-QX, 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 BZX58550-B18-QX part is unused and in its original packaging.
Return procedure for BZX58550-B18-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX58550-B18-QX 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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BZT52C15-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
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SMAJ4744A-TP
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BZT52C3V6LP-7
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SMAZ12-13-F
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