Diodes Incorporated DDZ20ASF-7

Overview

DDZ20ASF-7 from Diodes Incorporated is a precision 0.5W surface-mount Zener diode with nominal zener voltage of 18.5 V (min 18.05 V, max 18.96 V) at 10 mA test current, 50 Ω maximum zener impedance, and ±5% tolerance, designed for voltage regulation and reference in space-constrained power management circuits.

For engineers reviewing the DDZ20ASF-7 datasheet, DDZ20ASF-7 pinout, DDZ20ASF-7 application, or DDZ20ASF-7 equivalent, key selection criteria include zener voltage tightness (±2.7%), low temperature coefficient (~+4.5 mV/°C), SOD323F package compatibility with automated assembly, and automotive-grade availability via AEC-Q101 qualification path.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to maintain stable output voltage under varying load and input conditions. Its 10 mA zener test current and 50 Ω dynamic impedance ensure predictable regulation across ambient temperatures from –65°C to +150°C.

The SOD323F package delivers 250°C/W junction-to-ambient thermal resistance on FR-4 PCBs, enabling reliable 500 mW power dissipation without heatsinking. Its cathode band marking and matte tin–plated copper alloy leadframe support robust solderability per MIL-STD-202.

Key Specifications

Pinout & Package

Package: SOD323F - ultra-compact surface-mount plastic package (2.50 mm × 1.25 mm × 0.95 mm), halogen- and antimony-free, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C18LT1G and MMSZ5246B-TP, DDZ20ASF-7 delivers superior thermal performance (250 vs. ≥350°C/W), tighter effective V_Z spread (±2.7% vs. ±5%), and smaller SOD323F footprint-making it optimal for high-density, thermally constrained, and precision-regulated designs.

Availability

DDZ20ASF-7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, medical sensor interfaces, and telecom protection circuits requiring stable component supply with consistent parametric performance across production lots.

Supply support for DDZ20ASF-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, specializing in high-reliability components for automotive, industrial, and computing markets.

The DDZxxASF–DDZxxDSF series targets precision voltage reference applications where tight V_Z tolerance, low leakage, and automotive-qualified packaging are essential for feedback stability and long-term calibration integrity.

FAQ

What is the maximum continuous power dissipation for DDZ20ASF-7 on standard FR-4 PCB?

DDZ20ASF-7 is rated for 500 mW continuous power dissipation when mounted on an FR-4 PCB with a 10 mm × 10 mm copper pad and board dimensions of 35 mm × 25 mm. This rating assumes still air conditions and accounts for its 250°C/W junction-to-ambient thermal resistance.

Does DDZ20ASF-7 meet automotive qualification standards?

DDZ20ASF-7 is manufactured in IATF 16949-certified facilities and supports PPAP documentation. While not pre-qualified to AEC-Q101 out-of-box, Diodes Incorporated offers AEC-Q101 qualification upon request for automotive programs requiring change-controlled release and extended reliability testing.

How does the temperature coefficient affect regulation accuracy over –40°C to +125°C?

At ~18.5 V, DDZ20ASF-7 exhibits a typical temperature coefficient of +4.5 mV/°C. Over a 165°C range, this contributes ±0.74 V drift, which is within its ±0.46 V initial tolerance band-enabling total regulation error under ±1.2 V across full industrial temperature range.

Can DDZ20ASF-7 replace older Zener diodes like 1N4742A in existing designs?

No direct drop-in replacement: DDZ20ASF-7 uses SOD323F (2.5 mm × 1.25 mm), while 1N4742A is DO-41 (5.2 mm × 2.7 mm). Electrical compatibility requires verifying that 18.5 V V_Z, 50 Ω Z_ZT, and 500 mW P_D meet the original design's regulation and thermal margins before layout revision.