Counterfeit and defect prevention
Visual and packaging inspection
Electrical performance verification
Service Email:
[email protected]
>
Z2SMB18
Diotec Semiconductor
ZENERDIODE,SMB,18V,2W,5%
35219 Pcs New Original In Stock
Zener Diode 18 V 2 W ±5% Surface Mount SMB (DO-214AA)
Request Quote
(Ships tomorrow)
*Quantity
Minimum 1
Minimum 1
5.0 / 5.0
- (268 Ratings)
Z2SMB18
Product Overview
12944386
DiGi Electronics Part Number
Z2SMB18-DGManufacturer
Diotec Semiconductor
Z2SMB18
Description
ZENERDIODE,SMB,18V,2W,5%Inventory
35219 Pcs New Original In Stock
Zener Diode 18 V 2 W ±5% Surface Mount SMB (DO-214AA)
Quantity
Minimum 1
Minimum 1
Purchase and inquiry
Warranty & Returns
How to Order
Shipping & Delivery
Quality Assurance
365 - Day Quality Guarantee - Every part fully backed.
90 - Day Refund or Exchange - Defective parts? No hassle.
Limited Stock, Order Now - Get reliable parts without worry.
Global Shipping & Secure Packaging
Worldwide Delivery in 3-5 Business Days
100% ESD Anti-Static Packaging
Real-Time Tracking for Every Order
Secure & Flexible Payment
Credit Card, VISA, MasterCard, PayPal, Western Union, Telegraphic Transfer(T/T) and more
All payments encrypted for security
Z2SMB18 Technical Specifications
Category
Diodes, Zener, Single Zener Diodes
Packaging
Strip
Series
-
Product Status
Active
Voltage - Zener (Nom) (Vz)
18 V
Tolerance
±5%
Power - Max
2 W
Impedance (Max) (Zzt)
6 Ohms
Current - Reverse Leakage @ Vr
1 µA @ 10 V
Operating Temperature
-50°C ~ 150°C (TJ)
Mounting Type
Surface Mount
Package / Case
DO-214AA, SMB
Supplier Device Package
SMB (DO-214AA)
Datasheet & Documents
Datasheets
Download Z2SMB18 Product Specification (PDF)
HTML Datasheet
Z2SMB18-DG
Environmental & Export Classification
RoHS Status
ROHS3 Compliant
Additional Information
Other Names
2721-Z2SMB18
Standard Package
30
Reviews
5.0/5.0-(Show up to 5 Ratings)
Dec 02, 2025
產品質量優良，長時間使用仍然表現出色，值得購買。
Dec 02, 2025
Leur diligence dans le service après-vente est exemplaire, même pour les demandes complexes.
Dec 02, 2025
Le service après-vente est vraiment à la hauteur, merci.
Dec 02, 2025
La livraison a été express et l'emballage très soigné. Tout était parfait.
Dec 02, 2025
J'adore que DiGi Electronics utilise des emballages respectueux de l'environnement, c'est un vrai plus.
Dec 02, 2025
早い発送と丁寧な梱包のおかげで安心して購入できました。とても良かったです。
Dec 02, 2025
DiGi Electronics made my remote working setup more accessible with their competitive pricing.
Dec 02, 2025
Their commitment to consistent product quality and upfront pricing is truly commendable.
Dec 02, 2025
This shopping experience was excellent; the packaging was secure and the product durable.
Dec 02, 2025
Fast shipping service! I was able to get my item very swiftly, saving me time and hassle.
Publish Evalution
Evalution Message
Please enter your review message.
Please post honest comments and do not post ilegal comments.
Frequently Asked Questions (FAQ)
Can the Z2SMB18 Zener diode safely handle repeated transient voltage spikes above 18V in a 12V automotive power rail application without degradation?
The Z2SMB18 is rated for 2W continuous dissipation and ±5% tolerance, but transient spikes—common in automotive environments—can exceed its safe operating area if not properly managed. While it can clamp brief overvoltage events, sustained or high-energy transients (e.g., load dump) may cause cumulative thermal stress. For reliable operation, pair the Z2SMB18 with a series current-limiting resistor and consider adding a TVS diode (e.g., SMAJ15A) for robust transient suppression. Always validate thermal rise under worst-case pulse conditions using I²t analysis to avoid premature failure.
Is the Z2SMB18 a suitable drop-in replacement for the BZX84C18LT1G in a 500mA regulator circuit, and what design risks should I evaluate?
Although both the Z2SMB18 (Diotec) and BZX84C18LT1G (ON Semiconductor) are 18V, 2W Zener diodes in SMB packages, the Z2SMB18 has a higher dynamic impedance (6Ω max vs. ~3Ω typical for BZX84C18LT1G), which may result in slightly poorer regulation under varying load currents. Additionally, the Z2SMB18’s reverse leakage is specified at 1µA @ 10V, whereas the BZX84C18LT1G typically leaks less at lower voltages. Before replacing, verify output voltage stability across your full load range and ensure thermal margins are maintained—especially if the PCB layout lacks adequate copper pour for heat dissipation.
How does the Z2SMB18 perform under high-temperature conditions near its 150°C TJ limit, and what derating practices are recommended for long-term reliability?
Operating the Z2SMB18 near its 150°C junction temperature significantly accelerates aging and increases the risk of parametric drift or thermal runaway. Diotec does not publish detailed derating curves, but industry practice recommends derating power dissipation by at least 50% when TJ exceeds 125°C. For mission-critical applications, maintain TJ below 125°C using thermal vias, enlarged solder pads, or adjacent copper areas. Monitor Zener voltage shift over temperature—±5% tolerance includes initial variation, but thermal cycling can exacerbate drift, affecting precision regulation circuits.
Can I use the Z2SMB18 in a bidirectional voltage clamping configuration for RS-485 line protection, or is it only suitable for unidirectional applications?
The Z2SMB18 is a standard unidirectional Zener diode and should not be used in bidirectional clamping configurations without additional components. Applying reverse polarity beyond its breakdown voltage in a bidirectional setup will forward-bias the diode, offering no protection and potentially damaging the device. For RS-485 protection, use a dedicated bidirectional TVS array (e.g., SM712 or PESD1CAN) or pair two Z2SMB18 diodes back-to-back—though this increases capacitance and cost. Always consider signal integrity; the Z2SMB18’s 6Ω impedance and package parasitics may distort high-speed differential signals if not carefully modeled.
What PCB layout considerations are critical when using the Z2SMB18 in a compact SMPS feedback loop to minimize noise coupling and thermal hotspots?
In switch-mode power supply (SMPS) feedback circuits, the Z2SMB18 must be placed as close as possible to the control IC’s reference pin to minimize loop inductance and susceptibility to switching noise. Use a solid ground plane beneath the diode and connect its cathode directly to a low-impedance node. Avoid routing high-di/dt traces near the Z2SMB18 to prevent magnetic coupling. Thermal management is equally vital: ensure the SMB pad connects to at least 2–4 cm² of 2oz copper to dissipate 2W effectively. Poor layout can lead to localized heating, Zener voltage drift, and unstable regulation—especially under dynamic loads.
Quality Assurance (QC)
DiGi ensures the quality and authenticity of every electronic component through professional inspections and batch sampling, guaranteeing reliable sourcing, stable performance, and compliance with technical specifications, helping customers reduce supply chain risks and confidently use components in production.
Z2SMB18 CAD Models
Diotec Semiconductor Z2SMB18 PCB symbols & footprints
productDetail
