Diodes Incorporated MMBZ5228BT-7-F

Overview

MMBZ5228BT-7-F from Diodes Incorporated is a 3.9 V, 150 mW surface-mount Zener diode in SOT-523 package, rated for 20 mA test current, 23 Ω dynamic impedance at 20 mA, and 10 µA reverse leakage at 1.0 V, used for precision voltage regulation and reference in space-constrained power management circuits.

For engineers reviewing the MMBZ5228BT-7-F datasheet, MMBZ5228BT-7-F pinout, MMBZ5228BT-7-F application, or MMBZ5228BT-7-F equivalent, key selection criteria include nominal Zener voltage tolerance (±5%), thermal resistance (833 °C/W), low-leakage performance at VR = 1.0 V, and compatibility with automated SMT assembly on FR-4 PCBs.

Technical Context

This device operates as a two-terminal voltage reference using planar silicon junction technology, optimized for stable breakdown behavior under DC and low-frequency transient conditions. Its 3.9 V nominal Zener voltage is specified at I_ZT = 20 mA with ±5% tolerance (3.71–4.10 V), and exhibits 23 Ω Zener impedance (Z_ZT) at that current.

Thermal derating begins above 25°C ambient, with full 150 mW power dissipation only at T_A ≤ 25°C; maximum operating temperature is +150°C. Reverse leakage remains ≤10 µA at V_R = 1.0 V, supporting low-power biasing and sensing applications.

Key Specifications

Pinout & Package

Package: SOT-523 - ultra-small plastic surface-mount case (1.6 mm × 0.8 mm × 0.5 mm), UL 94V-0 rated, moisture sensitivity level 1, lead-free matte tin plating over Alloy 42 leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX584C3V9 and MM3Z3V9T1G, MMBZ5228BT-7-F offers the smallest footprint (SOT-523) and lowest leakage (10 µA @ 1.0 V), making it optimal for miniaturized, battery-sensitive designs-though its 150 mW rating and ±5% tolerance require careful thermal and accuracy budgeting.

Availability

MMBZ5228BT-7-F is available at Aetrix Electronics and suitable for portable power monitoring, low-power sensor biasing, USB-C port protection, and industrial PLC input conditioning requiring stable component supply across high-mix, low-volume production runs.

Supply support for MMBZ5228BT-7-F 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.

This part belongs to the MMBZ52xxBT series of ultra-small-signal Zener diodes, engineered specifically for space-constrained voltage regulation, reference, and clamping in consumer, computing, and industrial applications.

FAQ

What is the maximum continuous Zener current for MMBZ5228BT-7-F?

The device is rated for 20 mA test current (I_ZT) at 3.9 V, but maximum continuous current depends on ambient temperature and PCB thermal design. At T_A = 25°C with recommended pad layout, 150 mW power dissipation limits I_Z to ~38 mA (150 mW ÷ 3.9 V). Derating applies above 25°C per Fig. 1 in DS30267 Rev. 11-2.

Is MMBZ5228BT-7-F suitable for use as a voltage reference in ADC circuits?

Yes-it delivers stable 3.9 V reference with 23 Ω dynamic impedance and ≤10 µA leakage at 1.0 V, making it appropriate for low-resolution or cost-sensitive ADC biasing. For high-precision systems, consider tighter-tolerance alternatives like MM3Z3V9T1G due to its ±3% voltage spread versus ±5% here.

Does this Zener diode have polarity marking, and how is it identified on the SOT-523 package?

Yes-polarity is marked on the top surface of the SOT-523 case. The cathode is indicated by a single horizontal bar or stripe adjacent to the cathode terminal; the anode is the opposite lead. Diagrams in DS30267 Rev. 11-2, page 4, confirm orientation relative to the marking code "KG3".

Can MMBZ5228BT-7-F replace a 3.3 V Zener in an existing design?

No-its nominal Zener voltage is 3.9 V (range 3.71–4.10 V), not 3.3 V. Substituting would raise the regulated or clamped voltage by ~0.6 V, potentially violating downstream IC absolute maximum ratings or altering trip thresholds. Use MMBZ5226BT (3.3 V) instead for direct replacement.