Diodes Incorporated DDZX33-7

Overview

DDZX33-7 from Diodes Incorporated is a surface-mount precision Zener diode with nominal zener voltage of 32.14–33.79 V at 5 mA test current, 75 Ω zener impedance at 5 mA, 300 mW power dissipation on FR-4 PCB, and ±5% voltage tolerance. It operates across –65°C to +150°C and is used for voltage regulation and reference in automotive-grade power supply monitoring circuits.

For engineers reviewing the DDZX33-7 datasheet, DDZX33-7 pinout, DDZX33-7 application, or DDZX33-7 equivalent, key selection criteria include zener voltage tightness (±5%), low leakage (<0.05 µA at 27 V), AEC-Q101 qualification, SOT23 package compatibility, and thermal resistance (417 °C/W) under standard PCB mounting.

Technical Context

This device functions as a two-terminal voltage reference diode operating in reverse breakdown mode. Its sharp knee characteristics and low dynamic impedance (75 Ω at I_ZT = 5 mA) enable stable regulation under varying load conditions. The 300 mW power rating is specified for FR-4 PCB with recommended pad layout per Diodes Inc. guidelines.

It exhibits a positive temperature coefficient (~0.08 %/°C at 33 V) as shown in Figure 19, making it suitable for mid-to-high-voltage reference applications where moderate TC stability is acceptable. The SOT23 package supports automated assembly and meets halogen- and antimony-free "Green" requirements.

Key Specifications

Pinout & Package

Package: SOT23 - surface-mount plastic package with three terminals, 0.008 g mass, UL 94V-0 rated molding compound, and matte tin annealed terminals solderable per MIL-STD-202.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C33 and MMSZ5256ET1G, DDZX33-7 delivers verified AEC-Q101 reliability, tighter production V_Z consistency, and guaranteed 75 Ω impedance - making it the sole choice for safety-critical automotive voltage supervision where qualification and parametric stability are non-negotiable.

Availability

DDZX33-7 is available at Aetrix Electronics and suitable for automotive battery monitoring, industrial power supply reference, LED driver overvoltage protection, and test equipment voltage calibration requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for DDZX33-7 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.

DDZX33-7 belongs to the DDZX series of precision Zener diodes engineered for high-reliability voltage regulation in automotive and industrial applications, emphasizing tight tolerance, low leakage, and AEC-Q101 qualification.

FAQ

What is the maximum reverse voltage (V_R) before significant leakage occurs in DDZX33-7?

At V_R = 27 V, the maximum reverse leakage current is 0.05 µA per datasheet specification. This value is measured under pulsed conditions to minimize self-heating, and leakage remains below 1 µA up to 30 V. Exceeding 33.79 V risks entering uncontrolled breakdown unless current is strictly limited by external series resistance.

Can DDZX33-7 be used in parallel for higher power dissipation?

No - Zener diodes exhibit negative temperature coefficients at this voltage range and cannot be reliably paralleled due to thermal runaway risk. Each DDZX33-7 must operate independently with its own current-limiting resistor. For higher power needs, consider using a single higher-rated Zener or a series-pass regulator topology.

Is the SOT23 package of DDZX33-7 compatible with standard reflow profiles?

Yes - the SOT23 package uses matte tin annealed terminals compliant with IPC-J-STD-020 moisture sensitivity level 1, supporting standard Pb-free reflow profiles (peak 260°C, 20–40 sec above 217°C). No pre-bake is required, and the device withstands multiple reflow cycles without degradation.

Does DDZX33-7 have a specified temperature coefficient (TC) for V_Z?

Yes - Figure 19 shows a typical temperature coefficient of approximately +0.08 %/°C for the 33 V variant. This means V_Z increases by ~26.4 mV per °C rise across the –65°C to +150°C range, consistent with mid-voltage Zener devices exhibiting positive TC behavior.