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Diodes Incorporated BZX84C18W-7
- Part No.:
- BZX84C18W-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SC-70, SOT-323
- Datasheet:
-
BZX84C18W-7.pdf
- Description:
- DIODE ZENER 18V 200MW SOT323
- Quantity:
- Payment:
- Shipping:
Inventory:8,128
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Product details
Overview
BZX84C18W-7 from Diodes Incorporated is a 18 V, 200 mW surface-mount Zener diode in SOT-323 package, rated for 5 mA test current with ±0.6 V tolerance (16.8–19.1 V), 45 Ω dynamic impedance at 5 mA, and 0.1 µA reverse leakage at 12.6 V. It provides precision voltage regulation in low-power analog reference and overvoltage protection circuits.
For engineers reviewing the BZX84C18W-7 datasheet, BZX84C18W-7 pinout, BZX84C18W-7 application, or BZX84C18W-7 equivalent, key selection criteria include nominal Zener voltage, power dissipation limit, temperature coefficient (+12.4 to +16.0 mV/°C), reverse leakage at VR, and SOT-323 thermal resistance (625 K/W).
Technical Context
This Zener diode operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load or supply conditions. Its planar die construction ensures consistent breakdown characteristics and low noise performance.
It exhibits a positive temperature coefficient above ~5 V, enabling predictable drift compensation in temperature-sensitive references. The device is characterized at 25°C with pulse testing to minimize self-heating, and derates linearly to zero power at 150°C ambient per the published curve.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V nominal, 16.8–19.1 V range at IZT = 5 mA - defines regulation setpoint tolerance |
| Power Dissipation (PD) | 200 mW at TA = 25°C - limits continuous current to ~11 mA at 18 V |
| Zener Impedance (ZZT) | 45 Ω at IZT = 5 mA - determines output voltage variation under load changes |
| Reverse Leakage (IR) | 0.1 µA max at VR = 12.6 V - ensures minimal quiescent current in standby regulation |
| Temp. Coefficient (αVZ) | +12.4 to +16.0 mV/°C at IZT = 5 mA - quantifies voltage drift with ambient temperature |
| Package | SOT-323 - enables high-density PCB layout with 0.006 g mass and JEDEC-compliant reflow profile |
Pinout & Package
SOT-323 package with three terminals: anode (pin 1), cathode (pin 2), and no internal connection (pin 3). Cathode marked by band on top view; polarity confirmed by schematic diagram in DS30066 Rev. 15-2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration |
| Cathode (Pin 2) | Breakdown voltage reference terminal | Connected to regulated output node; marked with band on package |
| NC (Pin 3) | No internal connection | Unused terminal; electrically isolated from die and must not be soldered to plane |
Key Features
| Feature | Design Value |
|---|---|
| Planar die construction | Enables tight VZ tolerance control and repeatable Zener impedance across production lots |
| 200 mW power rating | Supports regulation in low-current signal conditioning paths without heatsinking |
| Lead-free / RoHS-compliant plating | Matte tin finish over Alloy 42 leadframe meets IPC-J-STD-020D Level 1 moisture sensitivity |
| Green molding compound | Halogen-free UL 94V-0 plastic housing reduces environmental impact and supports end-of-life compliance |
Applications
| Power Supply Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Stabilizing feedback voltage in low-power LDO regulators or DC-DC converter error amplifiers. IC Role / Device Role / Timing Role: Provides fixed 18 V reference point for comparator or op-amp input. Use Value: Maintains ±0.6 V regulation window under 5 mA load, minimizing output drift across line and load variations. | Use Scenario: Protecting microcontroller I/O pins from transient surges exceeding 18 V. IC Role / Device Role / Timing Role: Shunts excess energy to ground when input exceeds Zener breakdown threshold. Use Value: Limits clamping voltage to ≤19.1 V with <0.1 µA leakage below 12.6 V, preserving signal integrity during normal operation. |
| Temperature Sensor Bias | ADC Reference Divider |
Use Scenario: Generating bias current for silicon bandgap temperature sensors requiring stable excitation. IC Role / Device Role / Timing Role: Supplies constant current via series resistor to sensor element. Use Value: Delivers predictable 5 mA test current with <45 Ω dynamic impedance, reducing current-source error due to supply ripple. | Use Scenario: Scaling down 3.3 V or 5 V system rails to match ADC input full-scale range. IC Role / Device Role / Timing Role: Forms upper leg of precision resistive divider with matched low-tolerance resistor. Use Value: Enables 18 V reference stability with +12.4 to +16.0 mV/°C TC, allowing calibration of thermal drift in measurement chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBZ5245B-7-F | 200 mW, 18 V nominal, 16.2–19.8 V tolerance, 30 Ω ZZT, SOT-23 package | Lower ZZT improves regulation accuracy but larger SOT-23 footprint increases board area | Select for tighter impedance-critical references where space permits |
| BZX84-C18LT1G | 200 mW, 18 V nominal, 16.8–19.1 V tolerance, 45 Ω ZZT, SOT-23 package | Same electrical specs but different marking and packaging; requires pad layout adaptation | Select for second-source continuity if SOT-23 assembly infrastructure exists |
Compared with BZX84C18W-7, MMBZ5245B-7-F offers lower impedance at cost of larger footprint, while BZX84-C18LT1G matches spec but demands SOT-23 layout revision-both require validation of thermal performance in target PCB stack-up.
Availability
BZX84C18W-7 is available at Aetrix Electronics and suitable for power supply reference, overvoltage clamp, and ADC reference divider applications requiring stable component supply and RoHS-compliant sourcing.
Supply support for BZX84C18W-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.
The BZX84 series belongs to Diodes' standard Zener diode product line, designed specifically for cost-effective, space-constrained voltage regulation and protection in consumer, industrial, and computing applications.
FAQ
What is the maximum reverse voltage before breakdown for BZX84C18W-7?
The BZX84C18W-7 begins controlled reverse breakdown at a nominal 18 V, with guaranteed minimum and maximum values of 16.8 V and 19.1 V respectively at 5 mA test current. Below 12.6 V, reverse leakage remains ≤0.1 µA, confirming non-conductive behavior in pre-breakdown region.
Can BZX84C18W-7 be used in parallel for higher power handling?
No-Zener diodes exhibit negative temperature coefficients below ~5 V and positive above, but even within the same batch, slight VZ mismatches cause current hogging. Parallel use risks thermal runaway and premature failure; derating or external ballast resistors are required, making discrete higher-power Zeners or active regulators preferable.
Is the SOT-323 package compatible with standard reflow profiles?
Yes-the SOT-323 package meets JEDEC J-STD-020D Level 1 moisture sensitivity and is qualified for standard lead-free reflow profiles with peak temperatures up to 260°C. Its 0.006 g mass and thin mold compound ensure uniform heating and minimal warpage during assembly.
How does temperature affect the 18 V regulation point?
At 5 mA test current, the BZX84C18W-7 exhibits a positive temperature coefficient ranging from +12.4 to +16.0 mV/°C. This means the Zener voltage increases by approximately 14 mV per °C rise in junction temperature, requiring thermal design consideration in enclosed or high-ambient environments.
BZX84C18W-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±6%
- Power - Max:
- 200 mW
- Impedance (Max) (Zzt):
- 45 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 12.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
BZX84C18W-7 FAQ
1.How can I place an order for BZX84C18W-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for BZX84C18W-7 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 BZX84C18W-7 reliable?
The price and inventory of BZX84C18W-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84C18W-7 is usually 5 days.
3.What payment methods are accepted for BZX84C18W-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84C18W-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BZX84C18W-7?
BZX84C18W-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BZX84C18W-7 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 BZX84C18W-7?
For technical support, including BZX84C18W-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84C18W-7 requirements.
6.How does Aetrix verify that BZX84C18W-7 is sourced from the original manufacturer or authorized distributors?
All BZX84C18W-7 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 BZX84C18W-7 meets industry standards.
7.What is the process for return or replacement of BZX84C18W-7?
All BZX84C18W-7 units undergo pre-shipment inspection (PSI). If there is an issue with BZX84C18W-7, 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 BZX84C18W-7 part is unused and in its original packaging.
Return procedure for BZX84C18W-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BZX84C18W-7 Tags
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