onsemi MMBZ5228BLT1

Overview

MMBZ5228BLT1 from onsemi is a 3.9 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board at 25°C, with 23 Ω dynamic impedance at 20 mA test current and 10 μA reverse leakage at 1 V reverse voltage - used for precision voltage reference and overvoltage protection in portable power rails.

For engineers reviewing the MMBZ5228BLT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, ESD robustness (Class 3, >16 kV HBM), and real-world use cases in space-constrained consumer electronics.

Technical Context

This device operates as a two-terminal voltage reference, conducting in reverse breakdown when cathode voltage exceeds anode by ≥3.9 V. Its 23 Ω Zener impedance at I_ZT = 20 mA ensures stable regulation under moderate load transients, while its 10 μA leakage at VR = 1 V minimizes quiescent current loss in battery-powered systems.

The SOT-23 package supports automated placement and reflow soldering per JEDEC J-STD-020, with maximum solder temperature of 260°C for 10 seconds. Thermal resistance is 556°C/W junction-to-ambient on FR-5 board, enabling operation up to +150°C junction temperature with appropriate PCB copper area.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount plastic package, 2.90 mm × 1.30 mm × 1.00 mm body size, void-free thermosetting epoxy case with corrosion-resistant finish. Cathode indicated by polarity band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C3V9 and MMBZ5228BS, MMBZ5228BLT1 offers optimal balance of space efficiency (SOT-23), low dynamic impedance (23 Ω), and production-ready Pb-free compliance - making it preferred for high-volume portable electronics requiring consistent 3.9 V clamping with minimal board area.

Availability

MMBZ5228BLT1 is available at Aetrix Electronics and suitable for USB interface protection, microcontroller reset supervision, portable audio biasing, and smart sensor reference applications requiring stable component supply and full RoHS compliance.

Supply support for MMBZ5228BLT1 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MMBZ52xxBLT1G series was designed specifically for space-constrained, low-power voltage regulation and transient suppression in handheld portables and high-density PC boards - emphasizing small size, ESD resilience, and thermal reliability.

FAQ

What is the exact Zener voltage tolerance of MMBZ5228BLT1?

The MMBZ5228BLT1 has a guaranteed Zener voltage range of 3.70 V (minimum) to 4.10 V (maximum) at 20 mA test current, corresponding to a ±5% tolerance around the nominal 3.9 V value. This specification is validated per onsemi's Electrical Characteristics table and applies at T_A = 25°C with pulse testing to minimize self-heating effects. The MMBZ5228BLT1 maintains this tolerance across its qualified operating temperature range.

Does MMBZ5228BLT1 have a connection on pin 2?

No, pin 2 of the MMBZ5228BLT1 is internally not connected (NC). As confirmed in the marking diagram and mechanical outline documentation, only pins 1 (anode) and 3 (cathode) are electrically active. Pin 2 must remain unconnected on the PCB - no trace, pad, or solder joint should be placed there, as it serves no functional role in the MMBZ5228BLT1 circuit operation.

What is the maximum allowable power dissipation for MMBZ5228BLT1 at 60°C ambient?

At 60°C ambient temperature, the MMBZ5228BLT1's power dissipation must be derated linearly from its 225 mW rating at 25°C using the specified 1.8 mW/°C derating factor. The allowable power is therefore 225 mW − (60°C − 25°C) × 1.8 mW/°C = 162 mW. This ensures junction temperature stays within the −65°C to +150°C limit when mounted on FR-5 board per datasheet Note 1.

Is MMBZ5228BLT1 suitable for automotive applications?

The standard MMBZ5228BLT1 is not AEC-Q101 qualified. However, the SZMMBZ5228BLT1G variant - which shares identical electrical characteristics including 3.9 V Zener voltage and 23 Ω impedance - is explicitly rated for automotive use, with AEC-Q101 qualification and PPAP capability. For automotive-grade deployment, engineers must specify SZMMBZ5228BLT1G instead of MMBZ5228BLT1.

How does the ESD rating of MMBZ5228BLT1 impact system-level protection design?

The MMBZ5228BLT1's Class 3 ESD rating (>16 kV HBM) means it can absorb substantial electrostatic discharge energy without degradation, reducing or eliminating the need for additional TVS diodes in many front-end protection schemes. When used as a clamp on low-speed signal lines or power rails, the MMBZ5228BLT1 itself contributes directly to system-level ESD robustness - provided layout follows good practices (short traces, low-inductance grounding) and the device is placed close to the entry point.