Diodes Incorporated DDZ4V3BSF-7

Overview

DDZ4V3BSF-7 from Diodes Incorporated is a precision 0.5W surface-mount Zener diode with nominal zener voltage of 4.17–4.43 V at 20 mA test current, ±2.5% tolerance, 130 Ω dynamic impedance at 1 kHz, and 10 µA maximum reverse leakage at 1 V reverse bias. It operates from −65 °C to +150 °C and is used for voltage regulation and reference in low-power analog circuits, power supply feedback loops, and overvoltage protection.

For engineers reviewing the DDZ4V3BSF-7 datasheet, DDZ4V3BSF-7 pinout, DDZ4V3BSF-7 application, or DDZ4V3BSF-7 equivalent, this part is selected for stable low-voltage reference generation where tight V_Z tolerance, low thermal resistance (250 °C/W), and SOD323F package compatibility with automated assembly are critical design requirements.

Technical Context

This Zener diode functions in reverse-biased breakdown mode, delivering a stable reference voltage across its cathode–anode terminals when biased above its specified V_Z threshold. Its 20 mA zener test current ensures operation within the flat region of the breakdown curve, minimizing voltage drift due to current variation.

Thermal performance is defined by R_θJA = 250 °C/W on FR-4 PCB (10 mm × 10 mm pad), enabling reliable operation up to +150 °C junction temperature. The device exhibits a positive temperature coefficient near 4.3 V (≈+2.0 mV/°C per Fig. 3), supporting predictable thermal drift compensation in reference designs.

Key Specifications

Pinout & Package

Package: SOD323F - molded plastic, 2-terminal surface-mount package with cathode band marking; dimensions: 1.25 mm (D) × 1.70 mm (E) × 0.68 mm (A typ); weight ≈ 0.004 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C4V3-7-F and MMSZ4V3T1G, DDZ4V3BSF-7 delivers tighter voltage tolerance in a smaller SOD323F package with superior thermal resistance-making it optimal for space- and accuracy-critical 4.3 V reference designs.

Availability

DDZ4V3BSF-7 is available at Aetrix Electronics and suitable for power supply feedback, overvoltage protection, sensor biasing, and precision voltage reference applications requiring stable component supply across automotive, industrial, and consumer electronics programs.

Supply support for DDZ4V3BSF-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.

DDZ4V3BSF-7 belongs to the DDZxx(x)SF precision Zener series designed specifically for stable, low-power voltage reference and regulation in space-constrained, thermally demanding applications.

FAQ

What is the maximum continuous Zener current for DDZ4V3BSF-7 at 25°C ambient?

The device supports up to 20 mA continuous Zener current at 25°C ambient when mounted on a standard FR-4 PCB with 10 mm × 10 mm copper pad. At this current, power dissipation is 86–89 mW (4.3 V × 20 mA), well below the 500 mW rating. Derating begins above 70°C ambient per the power derating curve in Figure 1.

Does DDZ4V3BSF-7 meet AEC-Q101 qualification for automotive use?

No-DDZ4V3BSF-7 is not AEC-Q101 qualified. While Diodes offers AEC-Q101 versions in the same SOD323F package (e.g., DDZ4V3BSFQ-7), this specific part number is intended for industrial and commercial applications. Automotive designs require explicit PPAP-capable, IATF 16949-manufactured variants.

How does the SOD323F package affect solder joint reliability compared to SOD-123?

The SOD323F's smaller 1.25 mm × 1.70 mm body and 0.403 mm pad pitch demand tighter stencil aperture control and optimized reflow profiling, but its matte tin annealed finish ensures excellent wetting and intermetallic formation. Reliability testing shows equivalent thermal cycling endurance to SOD-123 when process parameters are validated per J-STD-020 Level 1 moisture handling.

Can DDZ4V3BSF-7 replace a 4.3 V Zener in a TL431-based feedback circuit?

Yes-it is commonly used as the reference element for TL431 cathode biasing in secondary-side regulation. Its 4.17–4.43 V range aligns with TL431's 2.495 V reference, enabling precise output setpoint definition. Ensure series resistor limits cathode current to 0.2–10 mA to avoid exceeding the TL431's minimum cathode current requirement.