onsemi SZMM3Z4V3ST1G

Overview

SZMM3Z4V3ST1G from onsemi is a 4.3 V ±3% Zener diode in SOD−323 package, rated for 500 mW steady-state power dissipation, with 90 Ω max dynamic impedance at 5 mA test current and 1.0 μA max reverse leakage at 3.4 V, used for precision voltage reference and overvoltage protection in space-constrained portable electronics.

For engineers reviewing the SZMM3Z4V3ST1G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance (±3%), thermal resistance (250 °C/W on heatsink), ESD rating (>16 kV HBM), low capacitance (450 pF), and AEC−Q101 qualification for automotive use cases.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse bias above its specified Zener breakdown voltage of 4.17–4.43 V at 5 mA. Its tight 3% tolerance and low temperature coefficient (−3.5 mV/°C) support stable regulation across temperature variations.

Designed for surface-mount applications with minimal PCB footprint (1.7 mm × 1.25 mm), it delivers 500 mW power handling under optimized thermal conditions (0.72 mm² pad + 38 mm² copper heatsink), while maintaining Class 3 ESD robustness and RoHS compliance.

Key Specifications

Pinout & Package

SOD−323 surface-mount package: 1.70 mm × 1.25 mm × 0.85 mm body, cathode indicated by polarity band, Pb-free plating, UL 94 V−0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX384-B4V3,115 and MMSZ4V3ET1G, SZMM3Z4V3ST1G offers superior voltage accuracy, automotive qualification, and thermal performance in the smallest possible SOD−323 footprint-making it optimal for next-generation portable and automotive systems where board area and reliability are critical.

Availability

SZMM3Z4V3ST1G is available at Aetrix Electronics and suitable for smartphone power management, automotive infotainment supply, and industrial IoT sensor node applications requiring stable component supply, long-term lifecycle support, and AEC−Q101-compliant parts.

Supply support for SZMM3Z4V3ST1G 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 (Semiconductor Components Industries, LLC) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MM3Z/SZMM3Z series was designed specifically for high-density, space-constrained voltage regulation-emphasizing tight tolerance, low profile, and automotive-grade reliability in miniature SOD−323 packaging.

FAQ

What is the Zener voltage tolerance of SZMM3Z4V3ST1G?

The SZMM3Z4V3ST1G has a Zener voltage tolerance of ±3%, specified as 4.17 V minimum to 4.43 V maximum at 5 mA test current. This tight tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet and enables high-accuracy voltage referencing without calibration. The SZMM3Z4V3ST1G achieves this via process-controlled doping and post-trim screening, distinguishing it from standard ±5% Zeners like the MMSZ4V3ET1G.

Is SZMM3Z4V3ST1G qualified for automotive applications?

Yes, SZMM3Z4V3ST1G is AEC−Q101 qualified and PPAP capable, as explicitly stated in the "Specification Features" section of the onsemi datasheet. The "SZ" prefix denotes automotive and other applications requiring unique site and control change requirements. This qualification covers stress tests including temperature cycling, humidity bias, and mechanical shock-making SZMM3Z4V3ST1G suitable for engine control units, ADAS sensors, and infotainment systems where reliability is mission-critical.

What is the maximum power dissipation of SZMM3Z4V3ST1G under standard PCB conditions?

SZMM3Z4V3ST1G delivers 500 mW steady-state power dissipation when mounted on an FR−4 board with a 0.72 mm² pad and 38 mm² copper heatsink (per Note 2 in the Maximum Ratings table). Without the heatsink, its rating drops to 300 mW on a 1 cm² single-sided copper pad. Engineers must select thermal layout based on actual power demand: SZMM3Z4V3ST1G's 250 °C/W R_JA under heatsink conditions enables higher continuous current than non-heatsinked alternatives.

Does SZMM3Z4V3ST1G have ESD protection built-in?

Yes, SZMM3Z4V3ST1G features Class 3 ESD protection (>16 kV) per the Human Body Model, as documented in the "Specification Features" section. This level of robustness eliminates the need for discrete TVS diodes in many handheld and automotive interface circuits. The ESD rating applies directly to the SZMM3Z4V3ST1G die and package structure-not derived from external components-and is verified during AEC−Q101 qualification testing.

What is the reverse leakage current specification for SZMM3Z4V3ST1G?

SZMM3Z4V3ST1G specifies a maximum reverse leakage current (I_R) of 1.0 μA at V_R = 3.4 V and T_A = 25°C, per the Electrical Characteristics table. This low leakage supports ultra-low-power operation in battery-backed systems and sensor nodes. The value is measured under defined test conditions and remains stable across the −65°C to +150°C junction temperature range, making SZMM3Z4V3ST1G suitable for always-on monitoring applications.