onsemi MMSZ4684T3G

Overview

MMSZ4684T3G from onsemi is a 3.3 V, 500 mW surface-mount Zener diode in SOD−123 package, designed for precision voltage regulation and reference applications at low test current (IZT = 50 µA). It delivers stable reverse breakdown with ±5% tolerance, 1.5 V reverse leakage limit at VR = 1.5 V, and operates across −55°C to +150°C junction temperature range - commonly used in power supply feedback loops, overvoltage protection, and analog sensor biasing circuits.

For engineers reviewing the MMSZ4684T3G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (3.3 V), low IZT (50 µA), thermal resistance (RJA = 340°C/W), SOD−123 footprint compatibility, and AEC−Q101 qualification status for automotive-grade reliability validation.

Technical Context

This device functions as a two-terminal voltage reference diode operating in reverse-biased Zener breakdown mode. Its 3.3 V nominal regulation is specified at IZT = 50 µA, with dynamic impedance (ZZT) typically < 90 Ω at 1 mA and < 30 Ω at 20 mA, enabling stable regulation under light-load conditions.

The SOD−123 package supports automated placement and reflow soldering with UL 94 V−0 flammability rating and 260°C/10s maximum soldering temperature. Junction-to-ambient thermal resistance of 340°C/W defines its derating behavior above 75°C ambient, limiting usable power dissipation in compact PCB layouts.

Key Specifications

Pinout & Package

SOD−123 surface-mount plastic package (1.60 × 2.69 × 1.16 mm), void-free thermosetting case with cathode polarity band. Designed for high-density layout and automated pick-and-place.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C3V3 and MMSZ4684T1G, the MMSZ4684T3G offers optimal balance of ultra-low IZT operation, automotive qualification, and high-volume packaging - making it preferred for space-constrained, low-power, and automotive-grade designs requiring long-term supply continuity.

Availability

MMSZ4684T3G is available at Aetrix Electronics and suitable for automotive sensor biasing, industrial power supply feedback, and portable device overvoltage protection requiring stable component supply, long-lifecycle support, and AEC−Q101 compliance.

Supply support for MMSZ4684T3G 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MMSZ4xxxT1G series was developed to deliver high-reliability, low-power Zener regulation in miniature SOD−123 packages - targeting automotive electronics, portable instrumentation, and space-constrained industrial controls where precision, size, and qualification matter.

FAQ

What is the nominal Zener voltage and tolerance of the MMSZ4684T3G?

The MMSZ4684T3G has a nominal Zener voltage of 3.3 V with a tolerance of ±5%, specified at a test current (IZT) of 50 µA. The actual voltage range is guaranteed between 3.13 V and 3.47 V under those conditions. This tight tolerance supports accurate voltage referencing in feedback and bias circuits where stability is critical. The MMSZ4684T3G maintains this specification across its full operating temperature range of −55°C to +150°C.

Is the MMSZ4684T3G suitable for automotive applications?

Yes, the MMSZ4684T3G is AEC−Q101 qualified and PPAP capable, confirming its suitability for automotive applications including engine control units, body electronics, and ADAS sensors. It meets stringent reliability requirements for thermal cycling, humidity, and mechanical shock. The MMSZ4684T3G also carries the "SZ" prefix option (e.g., SZMMSZ4684T3G) for applications requiring dedicated automotive site control and change management.

What is the maximum power dissipation and thermal derating behavior of the MMSZ4684T3G?

The MMSZ4684T3G is rated for 500 mW total power dissipation on FR−5 board at lead temperature (TL) of 75°C, with linear derating of 6.7 mW/°C above that point. Its junction-to-ambient thermal resistance is 340°C/W, meaning a 150 mW load will raise junction temperature by ~51°C above ambient. The MMSZ4684T3G must be mounted on adequate copper area to avoid exceeding its +150°C maximum junction temperature in sustained operation.

How does the MMSZ4684T3G compare to the MMSZ4684T1G?

The MMSZ4684T3G and MMSZ4684T1G share identical electrical specifications, package (SOD−123), marking (CK), and qualification status - differing only in tape-and-reel packaging quantity: 10,000 units per reel for MMSZ4684T3G versus 3,000 for MMSZ4684T1G. The MMSZ4684T3G is optimized for high-volume production runs, while both parts are functionally interchangeable in design and layout. No PCB or schematic changes are needed when substituting one for the other.

What is the reverse leakage current specification for the MMSZ4684T3G?

The MMSZ4684T3G specifies a maximum reverse leakage current (IR) of 7.5 µA at VR = 1.5 V and TA = 25°C. This low leakage ensures minimal parasitic current draw in high-impedance bias networks and battery-operated systems. At higher reverse voltages (e.g., VR = VZ − 0.5 V), leakage remains well below 1 µA, supporting precision reference stability. The MMSZ4684T3G's leakage performance is confirmed across its full operating temperature range.