onsemi SMMSZ4688T1G

Overview

SMMSZ4688T1G from onsemi is a 4.7 V ±5% Zener diode in SOD−123 package, rated for 500 mW power dissipation at TL = 75°C, with 50 µA test current (IZT), 10 µA reverse leakage at 3 V (IR), and 150°C maximum junction temperature - used for precision voltage reference and overvoltage protection in low-power analog sensor interfaces.

For engineers reviewing the SMMSZ4688T1G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage tolerance, dynamic impedance at 1 mA/5 mA/20 mA, temperature coefficient near zero-crossing (~4.7 V), thermal resistance (RJL = 150°C/W), and AEC−Q101 qualification status for automotive-grade reliability.

Technical Context

The SMMSZ4688T1G operates as a two-terminal silicon Zener regulator with sharp reverse breakdown at 4.7 V nominal, optimized for stable reference generation under low-current conditions (IZT = 50 µA). Its thermal design supports operation up to +150°C junction temperature with 340°C/W junction-to-ambient resistance on FR−5 board.

It exhibits low dynamic impedance (ZZT) typical of mid-voltage Zeners - ~15 Ω at IZ = 1 mA, ~9 Ω at 5 mA, and ~6 Ω at 20 mA - enabling effective noise suppression in feedback paths. The device's ESD rating exceeds 16 kV (HBM Class 3) and complies with RoHS and Pb−Free requirements.

Key Specifications

Pinout & Package

SOD−123 surface-mount package (1.60 × 2.69 × 1.16 mm), void-free thermosetting plastic case with cathode band marking; polarity confirmed per mechanical outline: Pin 1 = Cathode, Pin 2 = Anode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C4V7LT1G, SMMSZ4688T1G offers superior thermal resistance (RJL = 150°C/W vs. ~200°C/W typical for SOT−23) and smaller footprint; versus MMSZ4700T1G, it delivers a fundamentally different regulation point essential for low-voltage analog references.

Availability

SMMSZ4688T1G is available at Aetrix Electronics and suitable for automotive sensor modules, industrial analog input protection circuits, and portable medical device bias networks requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SMMSZ4688T1G 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 MMSZ4xxxT1G series was designed specifically for high-reliability, low-power voltage regulation in space-constrained and thermally demanding environments - emphasizing precision Zener characteristics, AEC−Q101 qualification, and manufacturability in automated SMT lines.

FAQ

What is the nominal Zener voltage and tolerance of SMMSZ4688T1G?

The SMMSZ4688T1G has a nominal Zener voltage of 4.7 V with a tolerance of ±5%, corresponding to a guaranteed range of 4.47 V to 4.94 V at IZT = 50 µA and TA = 25°C. This tight tolerance makes SMMSZ4688T1G suitable for precision reference applications where stable low-voltage regulation is critical, such as sensor biasing and analog front-end protection.

Is SMMSZ4688T1G qualified for automotive applications?

Yes, SMMSZ4688T1G is AEC−Q101 qualified and PPAP capable, meeting stringent automotive reliability standards. It is explicitly listed in the datasheet as part of the SZ-prefix qualified family (though SMMSZ4688T1G itself carries the standard prefix, its process and testing align with automotive requirements). Engineers deploying SMMSZ4688T1G in body control units or ADAS sensor interfaces can rely on its validated performance across −55°C to +150°C.

What is the maximum power dissipation of SMMSZ4688T1G and under what conditions?

SMMSZ4688T1G is rated for 500 mW total power dissipation on FR−5 board at lead temperature (TL) = 75°C, derating linearly at 6.7 mW/°C above that temperature. This rating assumes proper PCB layout with minimum recommended footprint; exceeding this limit risks thermal runaway or accelerated parametric shift. The 500 mW capability supports sustained operation in compact, unventilated enclosures when using SMMSZ4688T1G as a shunt regulator.

Does SMMSZ4688T1G have ESD protection, and what level is specified?

Yes, SMMSZ4688T1G features an ESD rating of Class 3 (>16 kV) per the Human Body Model (HBM), as confirmed in the official onsemi datasheet. This high-level ESD robustness ensures reliable handling during automated assembly and protects downstream circuitry from electrostatic discharge events in end-use environments - a key advantage when integrating SMMSZ4688T1G into exposed I/O protection schemes.

What package type and dimensions does SMMSZ4688T1G use?

SMMSZ4688T1G uses the SOD−123 surface-mount package (Case 425, Style 1), measuring 1.60 mm × 2.69 mm × 1.16 mm. It features a cathode band marking and is optimized for high-speed pick-and-place assembly. The compact size and standardized footprint make SMMSZ4688T1G ideal for high-density PCBs where space is limited - especially in applications like wearable health monitors or automotive ECUs where board real estate is at a premium.