Diodes Incorporated DDZ27D-7

Overview

DDZ27D-7 from Diodes Incorporated is a surface-mount precision Zener diode optimized for voltage regulation and reference applications in space-constrained industrial and automotive circuits. It delivers a nominal Zener voltage of 26.29 V to 27.64 V at 5 mA test current, with maximum Zener impedance of 45 Ω at 5 mA and 250 Ω at 0.5 mA, operating across –65 °C to +150 °C with 470 mW power dissipation at 25 °C ambient.

For engineers reviewing the DDZ27D-7 datasheet, DDZ27D-7 pinout, DDZ27D-7 application, or DDZ27D-7 equivalent, key selection criteria include tight V_Z tolerance (±2.5% typical), low temperature coefficient (~0.08%/°C per Fig. 18), SOD123 package compatibility with automated assembly, and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This device operates as a two-terminal reverse-biased voltage reference, maintaining stable output voltage under varying load and temperature conditions. Its low dynamic impedance (45 Ω @ I_ZT = 5 mA) ensures minimal output variation during transient current changes, while its 0.01 g mass and SOD123 footprint support high-density PCB layouts.

The Zener breakdown mechanism provides predictable, repeatable regulation without external biasing circuitry. Thermal resistance of 425 °C/W (on minimal pad layout) and 266 °C/W (on 1 in² copper pad) defines its thermal management envelope, directly impacting long-term stability and power handling in real-world board environments.

Key Specifications

Pinout & Package

DDZ27D-7 uses the SOD123 surface-mount package with a single cathode band marking indicating the cathode terminal. The device has two terminals: anode and cathode, with no internal connections beyond the Zener junction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C27LT1G and MMSZ5256ET1G, DDZ27D-7 offers tighter V_Z tolerance and lower TC in identical SOD123 packaging-making it optimal for high-accuracy references where board space and thermal constraints are critical.

Availability

DDZ27D-7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive battery monitoring systems, medical sensor signal conditioning, and telecom line card biasing requiring stable component supply and full traceability.

Supply support for DDZ27D-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 with ISO/TS 16949 and ISO 14001 certifications.

The DDZ series targets precision voltage reference needs in compact, thermally constrained designs-emphasizing tight V_Z tolerance, low TC, and AEC-Q101 compliance for mission-critical regulation tasks.

FAQ

What is the maximum reverse voltage (V_R) that DDZ27D-7 can withstand before breakdown?

DDZ27D-7 is specified with a maximum reverse current (I_R) of 0.05 µA at V_R = 21.0 V, meaning it remains in high-impedance blocking mode below this voltage. Breakdown occurs at its rated Zener voltage range (26.29–27.64 V), confirmed by Figure 8 in DS30407 Rev. 21-2. Operation below 21.0 V ensures negligible leakage in standby or sensing modes.

Can DDZ27D-7 be used in place of a 27 V Zener with ±5% tolerance?

Yes-DDZ27D-7's tighter ±2.5% tolerance (26.29–27.64 V) improves regulation accuracy over generic ±5% devices like MMSZ5256ET1G (25.65–28.35 V). This reduces output voltage spread in feedback networks, lowering calibration overhead in production and enhancing long-term stability across temperature.

Does DDZ27D-7 require a heatsink in typical PCB applications?

No heatsink is required. With a thermal resistance of 425 °C/W on minimal pads and 266 °C/W on 1 in² copper, DDZ27D-7 dissipates up to 470 mW at 25 °C ambient. At 27 V and 10 mA bias (270 mW), junction temperature rise is ~114 °C-well within its 150 °C max rating when mounted on standard FR-4 with recommended pad layout.

Is DDZ27D-7 suitable for use in high-humidity environments?

Yes-its SOD123 package features UL 94V-0 molded plastic with moisture sensitivity level 1 (J-STD-020), meaning it can be stored indefinitely at ≤30 °C/60% RH without baking. The matte tin annealed terminals resist oxidation, ensuring solderability and long-term reliability in humid industrial enclosures or under-hood automotive zones.