Diodes Incorporated DDZ33CSF-7

Overview

DDZ33CSF-7 from Diodes Incorporated is a precision 0.5W surface-mount Zener diode in SOD323F package, delivering tightly regulated 30.90–32.50 V Zener voltage at 5 mA test current, with 65 Ω dynamic impedance and <0.07 µA reverse leakage at 29.4 V, used for voltage reference and overvoltage protection in power supply feedback loops.

For engineers reviewing the DDZ33CSF-7 datasheet, DDZ33CSF-7 pinout, DDZ33CSF-7 application, or DDZ33CSF-7 equivalent, this part supports high-stability analog references, low-power sensor biasing, and compact LDO/DC-DC feedback networks where ±2.5% V_Z tolerance and thermal coefficient <±5 mV/°C are critical.

Technical Context

This Zener diode operates in reverse breakdown mode with specified test conditions: I_ZT = 5 mA, pulse duration <40 ms to minimize self-heating, and measurement at T_A = +25°C. Its thermal resistance (R_θJA = 250°C/W) is defined on FR-4 PCB with 10 mm × 10 mm copper pad.

The device exhibits a negative temperature coefficient below ~5 V and transitions toward zero/near-zero TC near 33 V - confirmed by Figure 3 in DS31987 Rev. 23-2 - enabling stable reference performance across -65°C to +150°C operating range without external compensation.

Key Specifications

Pinout & Package

Package: SOD323F - ultra-compact plastic molded case (UL 94V-0), 2.50 mm height (He), 1.70 mm width (E), 1.25 mm length (D), matte tin-plated copper alloy leadframe, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C33LT1G and MMSZ5260B-TP, DDZ33CSF-7 offers superior V_Z tolerance (±2.5% vs ±5%), lower Z_ZT (65 Ω vs 70–80 Ω), and smallest footprint - making it optimal for high-accuracy, space-limited industrial and automotive power management.

Availability

DDZ33CSF-7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, precision sensor signal conditioning, and medical diagnostic equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for DDZ33CSF-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, serving industrial, computing, communications, and consumer markets with high-reliability components.

This device belongs to the DDZxxCSF precision Zener series designed specifically for high-stability voltage reference and clamping in space-constrained, thermally demanding environments - emphasizing tight tolerance, low leakage, and automotive-grade process control.

FAQ

What is the maximum continuous Zener current for DDZ33CSF-7 at 25°C ambient?

The maximum continuous Zener current is derived from P_D = 500 mW and V_Z ≈ 31.7 V, yielding I_Z(max) ≈ 15.8 mA. However, the datasheet specifies I_ZT = 5 mA for parameter characterization, and operation above this requires thermal derating per Figure 1 - at 25°C, full 500 mW is allowed, but junction temperature must stay ≤150°C.

Does DDZ33CSF-7 meet AEC-Q101 qualification for automotive use?

No - the DDZ33CSF-7 is not AEC-Q101 qualified. The datasheet explicitly states that automotive-qualified parts require PPAP capability and IATF 16949 manufacturing; this variant is intended for industrial and commercial applications. For automotive use, Diodes recommends contacting their sales team for AEC-Q101-compliant alternatives such as the BZT52-B33 series.

How does the SOD323F package affect thermal performance compared to SOD-123?

The SOD323F package has higher thermal resistance (R_θJA = 250°C/W) than SOD-123 (typically ~200°C/W) due to smaller copper pad area and thinner leads. This means for the same 500 mW dissipation, junction temperature rises ~12.5°C higher in SOD323F - requiring careful PCB copper pour design to maintain reliability in high-ambient environments.

Can DDZ33CSF-7 replace a 33 V Zener in a TL431-based shunt regulator?

Yes - its 30.90–32.50 V range aligns with typical TL431 feedback thresholds (e.g., 2.495 V reference × (1 + R1/R2) ≈ 33 V). With 65 Ω Z_ZT and sub-µA leakage, it provides lower noise and better regulation than generic 33 V Zeners, improving overall loop stability and output accuracy in precision supplies.