onsemi MM3Z51VC

Overview

MM3Z51VC from onsemi is a 51 V ±5% tolerance Zener diode in SOD−323FL package, rated for 200 mW power dissipation, 169 Ω zener impedance at 2 mA test current, and 35.7 V reverse breakdown voltage at 0.045 µA leakage. It provides precision voltage regulation in low-power reference and protection circuits.

For engineers reviewing the MM3Z51VC datasheet, pinout, applications, or equivalent options, key selection criteria include its 51 V nominal zener voltage, ±5% tolerance, 200 mW power rating, SOD−323FL footprint compatibility, and low-leakage performance at VR = 35.7 V.

Technical Context

This device operates as a two-terminal voltage reference, conducting in reverse bias above its specified zener voltage (48.45–53.55 V) with controlled dynamic impedance. Its thermal resistance is 595 °C/W when mounted on PCB with minimum land pad, limiting continuous power handling under ambient conditions.

The MM3Z51VC uses silicon planar epitaxial construction, delivers stable regulation at IZT = 2 mA, and exhibits VF ≤ 1.0 V forward voltage at IF = 10 mA. It is Pb-free, RoHS-compliant, and qualified for operation from −65 °C to +150 °C storage temperature.

Key Specifications

Pinout & Package

SOD−323FL is a two-terminal surface-mount package with cathode marked by a band. The device has no active pins beyond anode and cathode terminals, both accessible via standard PCB land pattern per onsemi's mechanical drawing 98AON79864E.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MM3Z51VC, the BZX384-B51 offers higher power margin but looser impedance control at typical bias, while MMBZ5255B-7-F delivers far lower zener impedance at higher test current-making it preferable for dynamic load regulation, though its SOT-23 footprint increases layout area by ~2.5×.

Availability

MM3Z51VC is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery monitoring, and automotive body control module wake-up circuits requiring stable component supply and full RoHS compliance.

Supply support for MM3Z51VC 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 series is designed for compact, high-reliability voltage reference and overvoltage protection in space-constrained portable and embedded systems where SOD−323FL footprint and ±5% tolerance are critical.

FAQ

What is the nominal zener voltage and tolerance of MM3Z51VC?

The MM3Z51VC has a nominal zener voltage of 51 V with a tolerance of ±5%, meaning its actual zener voltage falls between 48.45 V and 53.55 V when tested at I_ZT = 2 mA. This tolerance is confirmed in the Electrical Characteristics table of the official onsemi datasheet (Rev. 3, August 2023), and applies across the full operating temperature range. The MM3Z51VC maintains this specification in its SOD−323FL package without derating.

What is the maximum power dissipation rating for MM3Z51VC?

The MM3Z51VC is rated for 200 mW maximum power dissipation at T_A = 25 °C when mounted on a PCB with minimum land pad. Its thermal resistance is 595 °C/W, so power must be reduced above ambient temperatures to avoid exceeding the 150 °C maximum junction temperature. This 200 mW limit is specified in the Absolute Maximum Ratings table and directly constrains continuous regulation current to approximately 3.9 mA at 51 V. The MM3Z51VC must not be operated beyond this rating without thermal derating.

What package type does MM3Z51VC use, and what are its key mechanical features?

The MM3Z51VC uses the SOD−323FL package (Case 477AB), measuring 1.7 mm × 1.25 mm × 0.95 mm with matte tin (Sn) finish. It features a cathode band marking, complies with JEDEC standards for SOD-323 outlines, and is Pb-free and RoHS-compliant. The package is optimized for automated placement and reflow soldering. Mechanical dimensions and land pattern recommendations are documented in onsemi drawing 98AON79864E. The MM3Z51VC shares this exact package with the full MM3Z2V4C–MM3Z75VC family.

How does the zener impedance of MM3Z51VC affect its regulation performance?

The MM3Z51VC has a maximum zener impedance (Z_ZT) of 169 Ω at I_ZT = 2 mA, which determines how much its output voltage varies with changes in current. Lower impedance yields tighter regulation; at 169 Ω, a 1 mA load shift causes ~0.17 V deviation. This value is measured using 60-Hz AC superimposed on DC bias, per onsemi test methodology. The MM3Z51VC's Z_ZT is higher than some alternatives (e.g., MMBZ5255B-7-F at 17 Ω), reflecting its optimization for low-current, space-constrained applications rather than high-dynamic-load scenarios.

What is the reverse leakage current specification for MM3Z51VC, and at what voltage is it measured?

The MM3Z51VC specifies a maximum reverse leakage current (I_R) of 0.045 µA at a reverse voltage (V_R) of 35.7 V. This parameter ensures minimal current draw in high-impedance bias networks and voltage-monitoring circuits where leakage could cause measurement error or false triggering. The value is guaranteed across temperature and is distinct from breakdown behavior - the device remains non-conductive below its 48.45 V minimum zener voltage. This I_R spec is explicitly listed in the Electrical Characteristics table for MM3Z51VC in the onsemi datasheet.