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Nexperia USA Inc. BZX58550-C18-QX
- Part No.:
- BZX58550-C18-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BZX58550-C18-QX.pdf
- Description:
- DIODE ZENER 18V 300MW SOD523
- Quantity:
- Payment:
- Shipping:
Inventory:4,359
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Product details
Overview
BZX58550-C18-QX from Nexperia is a low-current Zener voltage regulator diode in SOD523 (SC-79) package, providing 18 V nominal regulation at 50 µA test current with ±5 % tolerance, 225 Ω differential resistance at 5 mA, and qualified to AEC-Q101 for automotive power rail stabilization and low-bias reference applications.
For engineers reviewing the BZX58550-C18-QX datasheet, BZX58550-C18-QX pinout, BZX58550-C18-QX application, or BZX58550-C18-QX equivalent, key selection criteria include its ultra-low test current operation, thermal resistance of 350 K/W on 35 mm² cathode copper, 0.9 V forward voltage at 10 mA, and intentional leakage optimization for noise-sensitive analog supply rails.
Technical Context
This device operates as a two-terminal shunt regulator, maintaining stable 18 V output across load variations by conducting reverse current above its Zener knee. Its 50 µA test current enables use in micro-power circuits where quiescent current must remain below 100 µA.
The C-series variant features intentionally elevated leakage current versus B-series, reducing switching transients and high-frequency noise in precision analog supplies. It achieves this without compromising Zener voltage stability over −55 °C to +150 °C ambient range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 18 V at IZ = 50 µA - defines regulation point for low-bias reference design |
| Voltage Tolerance | ±5 % - supports cost-sensitive automotive sensor supply rails where tight tolerance is not required |
| Differential Resistance | 225 Ω at IZ = 5 mA - indicates moderate regulation stiffness suitable for non-critical biasing |
| Forward Voltage | 0.9 V at IF = 10 mA - enables predictable anode-to-cathode drop in reverse-polarity protection paths |
| Total Power Dissipation | 300 mW at Tamb ≤ 25 °C on 35 mm² cathode Cu - sets maximum continuous dissipation in standard FR4 layout |
| Junction Temperature Limit | 150 °C - allows operation in under-hood automotive environments with localized heating |
| AEC-Q101 Qualified | Yes - certified for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
Pinout & Package
Package: SOD523 (SC-79), plastic surface-mounted, 1.2 mm × 0.8 mm × 0.6 mm body, cathode marked by bar on top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (K) | Cathode | Connected to regulated voltage node; marking bar identifies this terminal; requires thermal copper pour for 300 mW operation |
| 2 (A) | Anode | Connected to ground or lower potential; forms shunt path when reverse-biased above 18 V |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low test current | 50 µA - enables regulation in battery-powered systems with sub-100 µA standby budgets |
| Optimized leakage profile | Intentional minor rise vs. B-series - reduces switching noise and improves transient response in analog references |
| Automotive qualification | AEC-Q101 compliant - validated for engine control units, body electronics, and ADAS sensor interfaces |
| Thermal performance | Rth(j-a) = 350 K/W on 35 mm² cathode Cu - supports reliable 250 mW operation in compact PCB layouts |
| Small-footprint packaging | SOD523 (1.2 × 0.8 mm) - saves board space in space-constrained modules like smart sensors and LED drivers |
Applications
| Automotive Sensor Bias Supply | Portable Device Reference Voltage |
|---|---|
Use Scenario: Providing stable 18 V bias to MEMS pressure sensor ICs in engine manifold modules. IC Role / Device Role / Timing Role: Shunt regulator establishing fixed reference voltage for sensor excitation and ADC reference scaling. Use Value: Enables accurate pressure measurement under wide temperature swings (−40 °C to +125 °C) while consuming <100 µA total system current. |
Use Scenario: Generating precise 18 V reference for low-power data loggers powered by coin-cell batteries. IC Role / Device Role / Timing Role: Low-quiescent Zener source for op-amp biasing and ADC reference in intermittent-sampling architectures. Use Value: Delivers stable regulation at 50 µA test current, extending battery life beyond 5 years in sleep-mode dominant operation. |
| Industrial IO Module Protection | LED Driver Feedback Clamp |
Use Scenario: Clamping 24 V field bus inputs against overvoltage transients in PLC digital input modules. IC Role / Device Role / Timing Role: Transient voltage suppressor and steady-state shunt limiter protecting downstream optocouplers and level shifters. Use Value: Withstands 40 W non-repetitive surges (100 µs) while maintaining 18 V clamping accuracy during sustained overvoltage events. |
Use Scenario: Stabilizing feedback node voltage in constant-current LED drivers using 18 V string configurations. IC Role / Device Role / Timing Role: Precision voltage clamp defining upper limit of feedback loop setpoint to prevent LED overcurrent. Use Value: 225 Ω dynamic impedance ensures minimal drift in current regulation across line and load variations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX58550-B18-Q | ±2 % tolerance, lower leakage, higher rdiff (250 Ω) | Better voltage accuracy but slower transient response due to reduced leakage | Select for precision reference needs where noise immunity is secondary to voltage stability |
| MMSZ5245B-TP | 20 V nominal, ±5 %, SOD-123 package (2.7 × 1.4 mm), 500 mW Ptot | Larger footprint, higher power handling, less suitable for ultra-compact automotive modules | Choose when board space permits and higher surge robustness (100 W peak) is required |
Compared with BZX58550-C18-QX, the B18-Q offers tighter voltage control at the expense of noise performance, while MMSZ5245B-TP trades miniaturization for higher power margin and legacy footprint compatibility-making the C18-QX optimal for space- and current-constrained automotive analog rails.
Availability
BZX58550-C18-QX is available at Aetrix Electronics and suitable for automotive sensor biasing, portable reference generation, industrial IO protection, and LED driver feedback clamping requiring stable component supply across production lifecycles.
Supply support for BZX58550-C18-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 focused on essential efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and consumer markets.
The BZX58550-Q series belongs to Nexperia's automotive-qualified Zener regulator portfolio, designed specifically for low-current, low-noise voltage reference and stabilization in harsh-environment electronic control units.
FAQ
What is the maximum continuous reverse power dissipation for BZX58550-C18-QX at 70 °C ambient?
At 70 °C ambient, derated power dissipation is approximately 210 mW based on the 350 K/W junction-to-ambient thermal resistance and 150 °C max junction temperature. This assumes mounting on FR4 with 35 mm² cathode copper area per datasheet condition [2]. Operation above this limit risks thermal runaway.
How does the C-series leakage optimization affect long-term reliability?
The intentional minor rise in leakage current is process-controlled and fully qualified under AEC-Q101 stress tests including HTOL and HTRB. It does not accelerate degradation; instead, it improves system-level noise immunity without impacting MTTF or failure-in-time metrics in automotive applications.
Can BZX58550-C18-QX be used in parallel for higher current capability?
No-Zener diodes exhibit negative temperature coefficient and mismatched VZ tolerances, causing current hogging and thermal instability when paralleled. For higher current regulation, use a single higher-power Zener or active shunt regulator architecture instead.
Is the SOD523 package compatible with standard reflow profiles for lead-free assembly?
Yes-the SOD523 package is rated for JEDEC J-STD-020D-compliant lead-free reflow, with peak temperature up to 260 °C. The recommended solder land pattern (Fig. 10) uses 0.5 mm pad width and 2.15 mm center-to-center spacing to ensure coplanarity and void-free joints.
BZX58550-C18-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- SC-79, SOD-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 300 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-C18-QX FAQ
1.How can I place an order for BZX58550-C18-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX58550-C18-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-C18-QX reliable?
The price and inventory of BZX58550-C18-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-C18-QX is usually 5 days.
3.What payment methods are accepted for BZX58550-C18-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX58550-C18-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX58550-C18-QX?
BZX58550-C18-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX58550-C18-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-C18-QX?
For technical support, including BZX58550-C18-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX58550-C18-QX requirements.
6.How does Aetrix verify that BZX58550-C18-QX is sourced from the original manufacturer or authorized distributors?
All BZX58550-C18-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-C18-QX meets industry standards.
7.What is the process for return or replacement of BZX58550-C18-QX?
All BZX58550-C18-QX units undergo pre-shipment inspection (PSI). If there is an issue with BZX58550-C18-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-C18-QX part is unused and in its original packaging.
Return procedure for BZX58550-C18-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX58550-C18-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
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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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SMAZ12-13-F
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