Diodes Incorporated DFLZ18Q-7

Overview

DFLZ18Q-7 from Diodes Incorporated is a 1.0W surface-mount power Zener diode in PowerDI123 package, with nominal Zener voltage 18V (min 16.8V, max 19.1V), Zener impedance 2Ω at 15mA test current, and thermal resistance junction-to-soldering point of 9°C/W. It is AEC-Q101 qualified for automotive applications and features a large exposed cathode pad for enhanced thermal dissipation in voltage regulation and overvoltage protection circuits.

For engineers reviewing the DFLZ18Q-7 datasheet, DFLZ18Q-7 pinout, DFLZ18Q-7 application, or DFLZ18Q-7 equivalent, key selection criteria include Zener voltage tolerance (±6%), low dynamic impedance, high surge capacity via patented interlocking clip design, RoHS-compliant lead-free finish, and thermal performance on FR-4 PCBs under automotive-grade reliability requirements.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable reference voltage across load variations and line transients. Its 18V nominal regulation is specified at I_ZT = 15mA with ±6% tolerance, and exhibits a positive temperature coefficient (+0.06%/°C min, +0.11%/°C max) ensuring predictable drift over -55°C to +150°C operating range.

The PowerDI123 package integrates an exposed cathode thermal pad directly bonded to the PCB, enabling 1.0W power dissipation on standard FR-4 with 2 oz. copper and 1"×1" pad layout. Junction-to-soldering-point thermal resistance of 9°C/W supports reliable operation in thermally constrained automotive modules and industrial power supplies.

Key Specifications

Pinout & Package

Package: PowerDI123 - molded plastic case with exposed cathode thermal pad (UL 94V-0), moisture sensitivity level 1, weight 0.01 g. Cathode identified by band marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C18LT1G and 1N4746A, DFLZ18Q-7 delivers superior surge robustness, automotive-grade reliability, and SMT-compatible thermal performance-making it the only choice for AEC-Q101-compliant 24V system protection where power density and transient immunity are critical.

Availability

DFLZ18Q-7 is available at Aetrix Electronics and suitable for automotive ECU protection, industrial 24V DC-DC regulation, and LED driver overvoltage clamping requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for DFLZ18Q-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, manufacturing, and sales operations across Asia, Europe, and North America.

The DFLZ series belongs to Diodes' AEC-Q101-qualified power Zener portfolio, engineered specifically for automotive and industrial voltage regulation where high surge capability, thermal efficiency, and green material compliance are mandatory.

FAQ

What is the maximum surge current DFLZ18Q-7 can withstand?

DFLZ18Q-7 is designed with a patented interlocking clip structure (US Patent #7,095,113) enabling ≥100A non-repetitive surge current handling per ISO 7637-2 Pulse 5a test conditions. This capability is validated under AEC-Q101 stress testing and confirmed in Diodes' application note AN-2001 for load dump protection circuits.

Does DFLZ18Q-7 require a heatsink on standard FR-4 PCB?

No external heatsink is required. With its PowerDI123 package featuring an exposed cathode thermal pad and R_θJS = 9°C/W, DFLZ18Q-7 achieves full 1.0W power dissipation on a 1.5" × 1.5" FR-4 board with 2 oz. copper and 1" × 1" solder pad-per Diodes' DS36898 Rev. 3 test setup.

How does the temperature coefficient affect regulation accuracy over temperature?

DFLZ18Q-7 has a temperature coefficient of +0.06%/°C (min) to +0.11%/°C (max). Over a -40°C to +125°C range, this results in a total V_Z shift of approximately +1.0V to +1.8V-well within the 16.8–19.1V specification window and suitable for non-critical regulation where absolute precision is less important than robustness.

Is DFLZ18Q-7 compatible with lead-free reflow profiles?

Yes. DFLZ18Q-7 uses matte tin annealed terminals over copper leadframe and is rated for lead-free reflow per JEDEC J-STD-020. Its MSL Level 1 rating means it can be stored indefinitely at ≤30°C/60% RH without baking, and it withstands peak reflow temperatures up to 260°C for 10 seconds per IPC/JEDEC standard.