Diodes Incorporated DDZX39F-7

Overview

DDZX39F-7 from Diodes Incorporated is a surface-mount precision Zener diode in SOT23 package, rated for 39 V nominal zener voltage (38.02–39.98 V), 5 mA test current, 85 Ω zener impedance at 1 kHz, and 300 mW power dissipation on FR-4 PCB. It delivers tight voltage tolerance and low leakage (<0.05 µA at 30 V) for voltage reference and regulation in automotive-grade power management circuits.

For engineers reviewing the DDZX39F-7 datasheet, DDZX39F-7 pinout, DDZX39F-7 application, or DDZX39F-7 equivalent, this part supports high-reliability voltage clamping, overvoltage protection, and precision biasing where AEC-Q101 qualification, thermal stability, and sharp breakdown characteristics are required.

Technical Context

This Zener diode operates in reverse-biased breakdown mode with tightly controlled V_Z tolerance (±2.5% typical across 38.02–39.98 V range) and exhibits low dynamic impedance (85 Ω @ 1 kHz, I_ZT = 5 mA), enabling stable regulation under varying load conditions. Its temperature coefficient is +0.08 %/°C near 39 V, supporting predictable drift behavior in industrial ambient ranges.

Designed for automated SMT assembly, it features matte tin-annealed terminals compliant with MIL-STD-202 solderability, moisture sensitivity level 1 per J-STD-020, and halogen/antimony-free "Green" molding compound rated UL 94V-0. The device is qualified to AEC-Q101 for automotive reliability but is not an automotive-specific variant (e.g., DDZX39FQ).

Key Specifications

Pinout & Package

Package: SOT23 - compact 3-pin surface-mount plastic case with 0.915 mm lead pitch, 2.40 mm body length, and 1.30 mm body width; optimized for high-density PCB layouts and reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C39 and MMSZ4702T1G, DDZX39F-7 offers the narrowest V_Z tolerance (±2.5%) and lowest Z_ZT (85 Ω) among SOT23 39 V Zeners, making it optimal for precision reference and low-noise clamping where voltage stability under load variation is critical.

Availability

DDZX39F-7 is available at Aetrix Electronics and suitable for automotive body electronics, industrial programmable logic controllers, medical infusion pump power supervision, and telecom base station bias reference requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for DDZX39F-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 DDZX series belongs to Diodes' precision Zener diode product line, engineered specifically for high-stability voltage reference and clamping in automotive, industrial, and medical applications demanding AEC-Q101 reliability and tight parametric control.

FAQ

What is the maximum reverse voltage (V_R) that DDZX39F-7 can withstand before breakdown?

The DDZX39F-7 begins controlled reverse breakdown at its specified zener voltage range of 38.02–39.98 V when tested at I_ZT = 5 mA. Below this threshold, reverse leakage remains ≤0.05 µA at 30 V. It is not rated for sustained operation above V_Z; exceeding V_Z by more than 10% risks thermal runaway unless current is strictly limited by external series resistance.

Is DDZX39F-7 compatible with lead-free reflow soldering profiles?

Yes - DDZX39F-7 uses matte tin-annealed terminals qualified per MIL-STD-202, Method 208, and is rated for standard JEDEC J-STD-020 lead-free reflow profiles (peak temperature up to 260 °C). Its moisture sensitivity level is 1, eliminating bake requirements prior to assembly.

Does DDZX39F-7 have a defined temperature coefficient, and how does it affect regulation accuracy?

At 39 V, DDZX39F-7 exhibits a positive temperature coefficient of approximately +0.08 %/°C (per Fig. 19). This means V_Z increases by ~31.2 mV per °C rise - a known, linear drift that can be compensated in closed-loop systems or accounted for in calibration routines across −40 to +125 °C operating ranges.

Can DDZX39F-7 replace older Zener diodes like 1N4739A in existing designs?

DDZX39F-7 is a direct functional replacement for 1N4739A in SOT23 footprint designs, offering tighter V_Z tolerance (±2.5% vs. ±5%), lower Z_ZT (85 Ω vs. 100 Ω), and AEC-Q101 qualification. However, pinout differs: 1N4739A is DO-41 (axial), while DDZX39F-7 is SOT23 (surface-mount); mechanical redesign is required for drop-in substitution.