Diodes Incorporated ZMM5225B-7

Overview

ZMM5225B-7 from Diodes Incorporated is a 3.0 V, 500 mW surface-mount Zener diode in MiniMELF (DO-213AA) glass package, rated for 20 mA test current, 29 Ω dynamic impedance at I_ZT, and -0.075 %/°C temperature coefficient. It provides precision voltage reference and overvoltage clamping in low-power analog circuits, including power supply feedback loops and sensor biasing networks.

For engineers reviewing the ZMM5225B-7 datasheet, ZMM5225B-7 pinout, ZMM5225B-7 application, or ZMM5225B-7 equivalent, key selection criteria include nominal Zener voltage tolerance (±5%), thermal resistance (300 °C/W), reverse leakage (50 µA @ 1.0 V), cathode-band polarity marking, and MiniMELF mechanical compatibility with automated SMT placement.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage regulation under controlled current conditions. Its 3.0 V nominal Zener voltage is specified at 20 mA test current (I_ZT) with ±5% tolerance (2.85–3.15 V), and exhibits a negative temperature coefficient of -0.075 %/°C - indicating decreasing V_Z with rising junction temperature.

The device features 29 Ω dynamic impedance (Z_ZT) at I_ZT, 1600 Ω knee impedance (Z_ZK) at 0.25 mA, and 50 µA maximum reverse leakage (I_R) at 1.0 V reverse bias. Its 500 mW power dissipation is thermally limited by a 300 °C/W junction-to-ambient thermal resistance under still-air conditions.

Key Specifications

Pinout & Package

MiniMELF package: hermetically sealed glass case with axial leads, cathode identified by single black band. No discrete pins - two-terminal device with anode and cathode terminals defined by polarity marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX55C3V0 and MMSZ5225B, ZMM5225B-7 offers superior thermal resistance (300 vs. 350 °C/W) and hermetic glass reliability in MiniMELF form factor - critical for space-constrained, high-reliability industrial and automotive voltage references.

Availability

ZMM5225B-7 is available at Aetrix Electronics and suitable for power supply feedback, sensor biasing, overvoltage clamping, and microcontroller I/O protection requiring stable component supply and consistent MiniMELF packaging.

Supply support for ZMM5225B-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 and manufacturing operations across Asia and the Americas.

ZMM52xxB series belongs to Diodes' precision Zener diode product line, engineered for stable voltage reference and clamping in space-constrained, thermally demanding applications such as industrial automation and automotive subsystems.

FAQ

What is the maximum continuous reverse current the ZMM5225B-7 can handle?

The ZMM5225B-7 is rated for 20 mA test current (I_ZT) and supports continuous reverse current up to its 500 mW power limit. At 3.0 V, this corresponds to ~167 mA maximum steady-state current, though practical operation is typically limited to ≤20 mA to maintain regulation accuracy and thermal safety.

Can ZMM5225B-7 be used in place of a 3.3 V Zener diode?

No - ZMM5225B-7 has a nominal Zener voltage of 3.0 V (2.85–3.15 V range), not 3.3 V. Substituting it for a 3.3 V part (e.g., ZMM5226B) would result in undershoot of the target regulation point by ~0.3 V, potentially causing system malfunction in voltage-critical circuits.

Is the MiniMELF package compatible with standard reflow soldering profiles?

Yes - the MiniMELF package is qualified for lead-free reflow per J-STD-020. Peak temperatures up to 260 °C are supported, provided ramp rates and dwell times comply with JEDEC Class 3 guidelines; thermal shock resistance is enhanced by the hermetic glass construction.

Does ZMM5225B-7 have a specified junction capacitance?

No specific junction capacitance value is listed in the DS30024 datasheet for ZMM5225B-7. However, Figure 2 shows typical junction capacitance for 3.0 V Zeners is ~100 pF at 2.0 V reverse bias, which applies to this part based on its position in the ZMM5221B–ZMM5267B family curve.