Diodes Incorporated ZMM5254B-7

Overview

ZMM5254B-7 from Diodes Incorporated is a 27 V, 500 mW surface-mount Zener diode in MiniMELF (DO-213AA) glass package, with nominal zener voltage tolerance ±4.5%, dynamic impedance 41 Ω at 4.6 mA test current, and positive temperature coefficient (+0.090 %/°C), used for precision voltage reference and overvoltage protection in low-power analog sensor interfaces.

For engineers reviewing the ZMM5254B-7 datasheet, ZMM5254B-7 pinout, ZMM5254B-7 application, or ZMM5254B-7 equivalent, key selection criteria include zener voltage accuracy at 4.6 mA, thermal resistance (300 °C/W), junction capacitance vs. voltage behavior, reverse leakage (<0.1 µA at 21.6 V), and MiniMELF solderability per MIL-STD-202 Method 208.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown with controlled zener voltage (25.65–28.35 V) at I_ZT = 4.6 mA. Its hemispherical glass MiniMELF package enables stable thermal performance up to +175 °C junction temperature and supports automated placement on high-reliability PCBs.

The ZMM5254B-7 exhibits a +0.090 %/°C temperature coefficient, indicating increasing zener voltage with rising temperature - critical for biasing circuits requiring predictable drift compensation. Its 600 Ω maximum zener impedance at knee current (I_ZK = 0.25 mA) defines low-current regulation capability in standby-mode power rails.

Key Specifications

Pinout & Package

Two-terminal device: anode and cathode. Cathode identified by single black band on glass body. No internal leads or substrate connections - terminals are the metallized ends of the glass-encapsulated silicon die.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX55C27 and MMSZ5254ET1G, ZMM5254B-7 delivers tighter voltage tolerance, lower thermal resistance, and superior pulse robustness in a MiniMELF platform optimized for automated SMT and high-reliability deployment.

Availability

ZMM5254B-7 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, automotive body control module reference, and medical portable device battery monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZMM5254B-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 centers across Asia and manufacturing in Taiwan and China.

ZMM52xxB is part of Diodes' precision Zener diode product line targeting high-stability voltage reference and clamping applications in automotive, industrial, and medical electronics where hermetic packaging and tight parametric control are essential.

FAQ

What is the maximum continuous power dissipation for ZMM5254B-7 at 85°C ambient?

At 85°C ambient, the ZMM5254B-7's power dissipation must be derated linearly from 500 mW at 25°C using its 300 °C/W thermal resistance. The allowable power is 500 mW × (1 − (85 − 25)/300) = 300 mW. Exceeding this risks junction temperature exceeding 175°C, accelerating parametric drift and failure.

Can ZMM5254B-7 be used in series for higher voltage references?

Yes - multiple ZMM5254B-7 devices may be stacked in series to achieve higher reference voltages (e.g., two units yield ~54 V), but voltage distribution depends on matching of Z_ZT and TC. For production use, parallel current balancing resistors (≥10 kΩ) are recommended to ensure equal current sharing and avoid thermal runaway.

Is the cathode band orientation standardized for MiniMELF devices?

Yes - the cathode band on ZMM5254B-7 is applied to one end of the glass body and aligns with JEDEC DO-213AA mechanical drawings. When mounted horizontally on PCB, the band corresponds to the cathode terminal; orientation is verified by continuity check to the banded end in forward bias (VF ≈ 1.5 V).

Does ZMM5254B-7 meet AEC-Q200 stress testing requirements?

No - ZMM5254B-7 is not AEC-Q200 qualified. While it operates from –65°C to +175°C and uses hermetic glass packaging, Diodes Incorporated does not list it in their AEC-Q200 stress-tested portfolio. For automotive-grade Zener references, consider the AZ-series (e.g., AZ27-M-07) which undergo full qualification.