Diodes Incorporated SMAZ18-13-F

Overview

SMAZ18-13-F from Diodes Incorporated is a 1.0W surface-mount Zener diode with nominal zener voltage of 18.0V (±5%), 15Ω maximum zener impedance at 15mA test current, 13.7V minimum regulation voltage at 1.0mA, and 56mA maximum zener current. It is used for voltage regulation and overvoltage protection in DC power rails of industrial control modules.

For engineers reviewing the SMAZ18-13-F datasheet, SMAZ18-13-F pinout, SMAZ18-13-F application, or SMAZ18-13-F equivalent, key selection criteria include zener voltage tolerance, thermal resistance (RθJA = 100°C/W), power derating above +50°C, and cathode-band polarity marking for automated placement.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and input conditions. Its 1.0W power rating at +25°C and linear derating (10mW/°C above +50°C) define usable thermal envelope on FR-4 PCBs with specified pad layout.

It exhibits 15Ω dynamic impedance at IZT = 15mA and 1.0µA maximum reverse leakage at VR = 13.7V, enabling precise clamping in low-power sensing and biasing circuits where stability across temperature is critical.

Key Specifications

Pinout & Package

Package: SMA (Surface Mount Axial), molded plastic case per UL 94V-0, cathode identified by band or notch, weight ≈ 0.064g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener regulation applications.

Compared with BZX84-C18LT1G and 1N4746A, SMAZ18-13-F delivers optimal balance of SMT manufacturability, 1.0W power capability, and thermal performance on standard PCBs-making it preferred for volume production of industrial power interfaces.

Availability

SMAZ18-13-F is available at Aetrix Electronics and suitable for industrial sensor conditioning, PLC input protection, DC-DC feedback networks, and ATE power monitoring requiring stable component supply across multi-year production cycles.

Supply support for SMAZ18-13-F 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, specializing in high-reliability components for industrial, automotive, and computing markets.

The SMAZ series belongs to Diodes' surface-mount Zener diode product line, engineered for automated assembly and stable voltage regulation in harsh-environment power management applications.

FAQ

What is the maximum reverse voltage this Zener can regulate without exceeding its power limit?

At +25°C ambient, SMAZ18-13-F regulates up to 18.0V at 56mA (1.0W). Above +50°C, power derates linearly at 10mW/°C; thus at +85°C, max allowable current drops to 650mA × (1.0W − 0.35W) / 18V ≈ 36mA. Derating must follow Fig. 1 in DS18015.

How is polarity identified on the SMAZ18-13-F package?

Polarity is marked by a cathode band on the body - the banded end is the cathode. This matches industry-standard SMA diode orientation and aligns with the cathode notch shown in Diodes' package outline drawings. No anode marking is present.

Can this device be used in forward-bias ESD protection?

Yes - SMAZ18-13-F has VF = 1.2V at 200mA forward current, making it suitable as a low-voltage forward clamp in bidirectional ESD protection schemes. Its 1.0W rating supports brief surge currents typical of IEC 61000-4-2 contact discharge events.

Is the 18.0V zener voltage guaranteed across temperature?

No - the 18.0V nominal value is specified at +25°C. Temperature coefficient is not published in DS18015, but typical Zener TC for this voltage range is +0.07%/°C. For precision references, use temperature-compensated Zeners or bandgap-based alternatives.