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Nexperia USA Inc. BZX58550-B18X
- Part No.:
- BZX58550-B18X
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Zener Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BZX58550-B18X.pdf
- Description:
- DIODE ZENER 18V 270MW SOD523
- Quantity:
- Payment:
- Shipping:
Inventory:9,656
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Product details
Overview
BZX58550-B18X from Nexperia is a low-current Zener voltage regulator diode in SOD523 (SC-79) package, designed for precision biasing and voltage reference in ultra-low-power circuits. It delivers a nominal 18 V regulation at 50 µA test current, with ±2 % tolerance, 225 Ω differential resistance at 5 mA, and 13.6 mV/K temperature coefficient - enabling stable operation in portable battery-powered sensors and microcontroller reset circuits.
For engineers reviewing the BZX58550-B18X datasheet, BZX58550-B18X pinout, BZX58550-B18X application, or BZX58550-B18X equivalent, key selection criteria include its 18 V nominal Zener voltage, ultra-low 50 µA test current, 300 mW power rating on FR4 PCB with 35 mm² copper, SOD523 footprint compatibility, and intentional leakage optimization for noise-sensitive analog front-ends.
Technical Context
This device operates as a two-terminal shunt voltage regulator, maintaining a stable 18 V reference across its cathode-anode terminals under reverse-bias conditions. Its Zener breakdown is specified at IZ = 50 µA, making it suitable for applications where quiescent current must remain below 100 µA.
The BZX58550-B18X belongs to the "B" tolerance series (±2 %), exhibits a positive temperature coefficient of +13.6 mV/K, and features optimized leakage behavior per AN90031 to reduce switching noise - distinguishing it from standard Zeners used in higher-current regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.6 V to 18.4 V at IZ = 50 µA - ensures tight 18 V reference for low-power analog sensing and MCU brown-out detection. |
| Differential Resistance (rdiff) | 225 Ω max at IZ = 5 mA - limits output impedance drift under small load variations in reference divider networks. |
| Temperature Coefficient (SZ) | +13.6 mV/K - provides predictable, linear VZ drift over −55 °C to +150 °C junction range. |
| Forward Voltage (VF) | ≤ 0.9 V at IF = 10 mA - enables use as low-drop rectifier or ESD clamp in dual-role designs. |
| Total Power Dissipation (Ptot) | 300 mW on FR4 PCB with 35 mm² cathode copper - defines maximum continuous reverse power before thermal derating. |
| Reverse Current (IR) | ≤ 0.05 µA at VR = 13.6 V - guarantees minimal leakage in high-impedance bias networks. |
Pinout & Package
SOD523 (SC-79) plastic surface-mount package: 1.2 mm × 0.8 mm × 0.6 mm body, ultra-small footprint ideal for space-constrained wearables and IoT nodes. Cathode identified by marking bar.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (K) | Cathode | Connected to regulated voltage node; marking bar indicates this terminal - must be tied to higher potential in shunt configuration. |
| 2 (A) | Anode | Connected to circuit ground or lower-potential rail; completes reverse-bias path for Zener conduction. |
Key Features
| Feature | Design Value |
|---|---|
| Low test current operation | Specified at 50 µA - enables direct use in nanoampere-biased sensor signal chains without external amplification. |
| Tight voltage tolerance | ±2 % (B-series) - reduces calibration overhead in precision ADC reference buffers and voltage monitors. |
| Optimized leakage profile | Intentional minor rise per AN90031 - suppresses transient noise during digital switching events in mixed-signal SoC power domains. |
| Thermal robustness | 150 °C max junction temperature - supports operation in sealed industrial enclosures without forced cooling. |
Applications
| Portable Sensor Biasing | Microcontroller Reset Reference |
|---|---|
Use Scenario: Providing stable 18 V bias to MEMS pressure sensor bridge in battery-powered environmental monitor. IC Role / Device Role / Timing Role: Shunt voltage reference regulating excitation voltage for Wheatstone bridge. Use Value: 50 µA test current minimizes drain on CR2032 coin cell; ±2 % tolerance avoids factory recalibration. |
Use Scenario: Generating precise 18 V threshold for external reset supervisor IC monitoring 24 V industrial PLC supply rail. IC Role / Device Role / Timing Role: Zener-based voltage reference input to reset comparator. Use Value: +13.6 mV/K tempco aligns with supervisor's internal reference drift, improving overvoltage trip accuracy across −40 °C to +85 °C. |
| Low-Power Analog Front-End | IoT Node Voltage Clamp |
Use Scenario: Setting reference point for op-amp gain stage in ultralow-power gas detector signal chain. IC Role / Device Role / Timing Role: Precision DC reference source for instrumentation amplifier common-mode level. Use Value: 225 Ω rdiff ensures <1 mV error under 1 µA load variation from photodiode leakage drift. |
Use Scenario: Clamping RF-coupled transients on 18 V LDO input in NB-IoT modem module. IC Role / Device Role / Timing Role: Fast-response shunt protector leveraging optimized leakage for reduced ringing. Use Value: AN90031 leakage tuning lowers high-frequency impedance discontinuity, cutting EMI by >6 dB in 10–100 MHz band. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX58550-C18 | ±5 % tolerance, identical 18 V nominal, same SOD523 package and 50 µA test current. | Acceptable where system-level calibration compensates for wider voltage spread. | Select when cost sensitivity outweighs need for factory-trimmed reference stability. |
| MMSZ5245B | 18 V nominal, ±5 %, SOD-123 package (2.7 mm × 1.4 mm), 500 mW Ptot, 200 Ω rdiff. | Requires larger PCB area; higher power handling suits higher-current bias networks. | Choose only if board layout allows SOD-123 and thermal margin exceeds 300 mW requirement. |
Compared with BZX58550-C18, the BZX58550-B18X offers tighter regulation critical for uncalibrated systems; versus MMSZ5245B, it trades package size and power headroom for superior space efficiency and leakage-noise performance in sub-100 µA designs.
Availability
BZX58550-B18X is available at Aetrix Electronics and suitable for portable sensor biasing, microcontroller reset reference, and low-power analog front-end applications requiring stable component supply with guaranteed long-term continuity.
Supply support for BZX58550-B18X 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 discrete and logic devices, with leadership in automotive-qualified and energy-efficient components.
The BZX58550 series belongs to Nexperia's low-current Zener portfolio, engineered specifically for ultra-low-power voltage reference and biasing in battery-operated and space-constrained electronics.
FAQ
What is the maximum reverse voltage the BZX58550-B18X can withstand before breakdown?
The BZX58550-B18X has a nominal Zener voltage of 18 V, with a guaranteed breakdown range of 17.6 V to 18.4 V at 50 µA test current. Its absolute maximum non-repetitive peak reverse voltage is not specified independently; instead, it is limited by the 40 W surge rating at 100 µs pulse width and the 300 mW steady-state dissipation on FR4 PCB with 35 mm² copper.
Can the BZX58550-B18X be used in forward-bias mode?
Yes - it functions as a standard silicon diode in forward bias, with VF ≤ 0.9 V at 10 mA. This dual-role capability allows use as both a Zener reference and an ESD protection element in compact interfaces, though its 200 mA absolute maximum forward current requires current-limiting resistors in most applications.
How does the "intentional minor rise of leakage current" benefit circuit design?
Per Application Note AN90031, this controlled leakage improves high-frequency transient response by reducing minority-carrier storage delay, thereby minimizing ringing and overshoot during fast voltage transitions - especially valuable in mixed-signal systems where digital switching couples noise into analog reference paths.
Is thermal derating required above 25 °C ambient?
Yes - the 300 mW total power dissipation rating applies only at Tamb ≤ 25 °C with specified PCB copper area. Thermal resistance from junction to ambient is 350 K/W under those conditions, so power must be linearly derated by 0.857 mW/°C above 25 °C to maintain Tj ≤ 150 °C.
BZX58550-B18X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- BZX58550
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-523
BZX58550-B18X FAQ
1.How can I place an order for BZX58550-B18X through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX58550-B18X 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-B18X reliable?
The price and inventory of BZX58550-B18X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX58550-B18X is usually 5 days.
3.What payment methods are accepted for BZX58550-B18X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX58550-B18X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX58550-B18X?
BZX58550-B18X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX58550-B18X 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-B18X?
For technical support, including BZX58550-B18X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX58550-B18X requirements.
6.How does Aetrix verify that BZX58550-B18X is sourced from the original manufacturer or authorized distributors?
All BZX58550-B18X 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-B18X meets industry standards.
7.What is the process for return or replacement of BZX58550-B18X?
All BZX58550-B18X units undergo pre-shipment inspection (PSI). If there is an issue with BZX58550-B18X, 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-B18X part is unused and in its original packaging.
Return procedure for BZX58550-B18X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX58550-B18X Tags
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MMBZ5240B-7-F
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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
onsemi
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SMAJ4744A-TP
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SMAZ12-13-F
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