Diodes Incorporated DFLZ18-7

Overview

DFLZ18-7 from Diodes Incorporated is a 1.0W surface-mount power Zener diode in PowerDI123 package, rated for 18V nominal Zener voltage (16.8–19.1V range), 25mA test current, 2Ω typical Zener impedance, and −55°C to +150°C operating temperature. It provides precision voltage regulation in power supply feedback loops, overvoltage protection circuits, and reference voltage generation for industrial power converters.

For engineers reviewing the DFLZ18-7 datasheet, DFLZ18-7 pinout, DFLZ18-7 application, or DFLZ18-7 equivalent, key selection criteria include its 1W FR-4 PCB power dissipation, JEDEC-qualified reliability, RoHS-compliant matte tin finish, cathode-band polarity marking, and thermal resistance of 9°C/W junction-to-soldering-point - critical for thermal design in compact DC/DC modules and automotive body control units.

Technical Context

This Zener diode operates in reverse breakdown mode with tightly controlled voltage tolerance (±5.6% at 18V) and low dynamic impedance (2Ω typ @ 25mA), enabling stable regulation under varying load and line conditions. Its 110°C/W junction-to-ambient thermal resistance assumes standard 1.5"×1.5" FR-4 PCB layout with 2 oz. copper and 1"×1" pad - essential for derating calculations in enclosed environments.

The device features a single PN junction with cathode-band terminal identification, optimized for low-capacitance operation (<10pF at 1V reverse bias), and exhibits a positive temperature coefficient (+0.06%/°C min, +0.11%/°C max) - supporting predictable drift behavior in temperature-compensated references.

Key Specifications

Pinout & Package

Package: PowerDI123 - surface-mount, 2-terminal molded plastic package with cathode band marking; dimensions: 1.78 mm × 3.70 mm × 0.98 mm (L × W × H); UL 94V-0 rated; moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C18LT1G and 1N4746A, DFLZ18-7 delivers superior thermal performance (9°C/W vs. 300°C/W or ~50°C/W), automotive-grade reliability, and surface-mount compatibility - making it the optimal choice for thermally demanding, high-volume SMT applications requiring long-term stability.

Availability

DFLZ18-7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, programmable logic controller (PLC) I/O protection, and telecom DC-DC converter reference circuits requiring stable component supply and long-lifecycle support.

Supply support for DFLZ18-7 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.

DFLZ18-7 belongs to the PowerDI® Zener diode product line, engineered specifically for high-reliability, surface-mount voltage regulation and protection in automotive, industrial, and communications infrastructure applications.

FAQ

What is the maximum continuous power dissipation for DFLZ18-7 on a standard PCB?

DFLZ18-7 is rated for 1.0W continuous power dissipation when mounted on a 1.5"×1.5" FR-4 PCB with 2 oz. copper and a 1"×1" thermal pad. Derating is required above +25°C ambient per the published power derating curve - e.g., 0.5W at +100°C ambient. This rating assumes no additional heatsinking or airflow.

Is DFLZ18-7 suitable for automotive applications?

Yes - DFLZ18-7 is qualified to JEDEC reliability standards referenced in AEC-Q, making it appropriate for non-safety-critical automotive subsystems such as body control modules, lighting drivers, and infotainment power rails. For full AEC-Q200 compliance, the automotive-grade variant DFLZ18Q-7 must be used.

How is polarity identified on the DFLZ18-7 package?

Polarity is indicated by a cathode band printed on the top surface of the PowerDI123 package. The banded end is the cathode terminal; the opposite end is the anode. This marking aligns with industry-standard Zener diode orientation and is verified in Diodes' official package drawings and tape-and-reel packaging documentation.

What is the typical Zener impedance and why does it matter?

DFLZ18-7 has a typical Zener impedance of 2Ω at 25mA test current. This low dynamic resistance ensures minimal output voltage variation under changing load currents - critical for maintaining regulation accuracy in feedback loops and reference circuits where even small ΔI_Z would otherwise cause unacceptable ΔV_Z.