onsemi MM5Z4678T1G

Overview

MM5Z4678T1G from onsemi is a 500 mW, 1.8 V nominal Zener voltage regulator diode in SOD−523 package, with 50 μA test current (IZT), 7.5 μA max reverse leakage at 1 V VR, and ±5% voltage tolerance. It provides precision low-voltage regulation for power rail clamping and reference applications in space-constrained portable electronics.

For engineers reviewing the MM5Z4678T1G datasheet, pinout, applications, or equivalent options, key selection factors include its 1.8 V Zener voltage, 500 mW power rating on FR-5 board, SOD−523 footprint compatibility, ESD robustness (>16 kV HBM), and automotive-grade SZ-series variant availability.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load or input conditions. Its 1.8 V nominal Zener voltage is specified at IZT = 50 μA with ±5% tolerance, and it exhibits low leakage (≤7.5 μA at VR = 1 V) and thermal stability over −55°C to +150°C junction temperature range.

The device uses a silicon planar Zener structure in a void-free thermosetting plastic SOD−523 case, rated for 260°C soldering (10 s), UL 94 V−0 flammability, and Pb−Free/RoHS compliance. Cathode polarity is marked by a band on terminal 1.

Key Specifications

Pinout & Package

SOD−523 surface-mount package with two terminals: cathode (marked with polarity band) and anode. Case is void-free thermosetting plastic, corrosion-resistant, UL 94 V−0 rated, and designed for reflow soldering at 260°C for 10 seconds.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MM5Z4678T1G, BZX584C1V8LT1G offers better leakage but requires more board space and lower power handling, while MMSZ4678T1G matches power and leakage but sacrifices miniaturization - making MM5Z4678T1G optimal for new high-density designs prioritizing size and ESD robustness.

Availability

MM5Z4678T1G is available at Aetrix Electronics and suitable for battery monitoring, low-voltage MCU reference, and USB-C port protection requiring stable component supply and consistent SOD−523 sourcing.

Supply support for MM5Z4678T1G 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 MM5Z4xxxTxG series targets space-constrained, low-power voltage regulation needs - especially in portable electronics and high-density PCBs where miniaturization and ESD resilience are critical.

FAQ

What is the nominal Zener voltage and tolerance of MM5Z4678T1G?

The MM5Z4678T1G has a nominal Zener voltage of 1.8 V with a tolerance of ±5%, measured at IZT = 50 μA and TL = 30°C ±1°C. The guaranteed range is 1.71 V to 1.89 V. This tight tolerance supports accurate voltage referencing in low-voltage digital systems where 1.8 V rails are common, and the MM5Z4678T1G maintains this specification across its full operating temperature range.

Does MM5Z4678T1G meet automotive qualification standards?

The MM5Z4678T1G itself is not AEC-Q101 qualified; however, its automotive-grade counterpart SZMM5Z4678T1G is AEC-Q101 qualified and PPAP capable. Both share identical electrical characteristics and SOD−523 packaging, but only the SZ-prefixed version meets automotive reliability and change-control requirements. For non-automotive industrial or consumer use, MM5Z4678T1G is fully suitable and RoHS compliant.

What is the maximum reverse leakage current for MM5Z4678T1G at 1 V reverse bias?

The maximum reverse leakage current (IR) for MM5Z4678T1G is 7.5 μA when reverse biased at VR = 1 V, tested at TA = 25°C. This value is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet. Low leakage ensures minimal quiescent current draw in always-on circuits, making the MM5Z4678T1G appropriate for battery-powered applications where standby power must be tightly controlled.

Can MM5Z4678T1G be used in place of a 1.8 V voltage reference IC?

MM5Z4678T1G can serve as a cost-effective, space-saving alternative to dedicated 1.8 V reference ICs in applications where moderate accuracy and temperature drift are acceptable. Unlike precision references, it lacks active compensation and exhibits typical Zener temperature coefficients (~−2 mV/°C near 1.8 V). For basic clamping or coarse referencing - especially where the MM5Z4678T1G's 500 mW surge capability adds value - it is a valid choice, but not for high-accuracy analog measurement.

What is the thermal resistance (RJA) of MM5Z4678T1G and how does it affect PCB layout?

The junction-to-ambient thermal resistance (RJA) of MM5Z4678T1G is 250°C/W, measured via infrared scan on FR-5 board. This high RJA reflects the SOD−523 package's limited thermal mass and surface area. To avoid exceeding the 150°C max junction temperature, designers must limit average power dissipation and consider copper pour or thermal vias beneath the pad - especially since the MM5Z4678T1G's 500 mW rating applies only at TL = 75°C and derates linearly above that point.