onsemi MMBZ5237ELT1G

Overview

MMBZ5237ELT1G from onsemi is a 225 mW surface-mount Zener diode in SOT-23 package, rated for 8.2 V nominal Zener voltage at 20 mA test current, with 500 Ω maximum dynamic impedance and 0.25 μA reverse leakage at 6.5 V. It provides precision voltage regulation in space-constrained power rails for portable electronics and high-density PCBs.

For engineers reviewing the MMBZ5237ELT1G datasheet, pinout, applications, or equivalent options, this part supports low-power voltage reference, overvoltage clamping, and bias stabilization where ±5% Zener tolerance, 16 kV HBM ESD rating, and thermal resistance of 556°C/W on FR-5 board are critical selection criteria.

Technical Context

This device operates as a two-terminal voltage reference using avalanche breakdown in silicon PN junction. Its Zener voltage is specified at IZT = 20 mA with tight 7.79–8.61 V range (±5%), and exhibits temperature coefficient near zero at ~8.2 V - confirmed by typical TC curves in Figure 1. The 2nd pin is internally unconnected, eliminating parasitic paths in layout.

Designed for automated SMT assembly, it features Pb-free plating, UL 94 V-0 flammability rating, and 260°C/10s soldering tolerance. Its 225 W peak pulse power (8 × 20 µs) enables transient suppression in low-energy surge events without derating concerns under standard operating conditions.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with void-free thermosetting case, corrosion-resistant finish, and cathode polarity band. Maximum soldering temperature: 260°C for 10 seconds. Flammability rating: UL 94 V-0.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBZ5237ELT1G, BZX84-C8V2LT1G offers higher power headroom but looser regulation at light loads, while MMBZ5237BS sacrifices ESD robustness and environmental compliance for mechanical compatibility with older layouts.

Availability

MMBZ5237ELT1G is available at Aetrix Electronics and suitable for USB interface protection, sensor biasing, microcontroller reset generation, and Li-ion battery monitoring requiring stable component supply and full RoHS compliance.

Supply support for MMBZ5237ELT1G 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 is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and edge applications - focused on enabling sustainable electronics innovation.

The MMBZ52xxELT1G series targets space-constrained, low-power voltage regulation in portable and high-density systems, emphasizing reliability, ESD resilience, and automated manufacturability in consumer and IoT devices.

FAQ

What is the Zener voltage tolerance for MMBZ5237ELT1G?

The MMBZ5237ELT1G has a Zener voltage range of 7.79 V to 8.61 V at I_ZT = 20 mA, representing ±5% tolerance around the nominal 8.2 V value. This tolerance is guaranteed across the full operating temperature range of −65°C to +150°C and is measured using pulsed test conditions to minimize self-heating effects. The MMBZ5237ELT1G datasheet specifies this range in the Electrical Characteristics table on page 2.

Is MMBZ5237ELT1G compatible with lead-free reflow processes?

Yes, MMBZ5237ELT1G is Pb-free and qualified for standard lead-free reflow profiles, including peak temperatures up to 260°C for 10 seconds. Its thermosetting plastic SOT-23 package and corrosion-resistant finish ensure reliability under IPC/JEDEC J-STD-020 moisture sensitivity level 1 conditions. The "G" suffix explicitly denotes Pb-free compliance per onsemi's packaging standards.

Does MMBZ5237ELT1G have a functional connection on pin 2?

No, pin 2 of the MMBZ5237ELT1G is internally unconnected (NC), as confirmed in the datasheet's pinout diagram (Style 8) and Electrical Characteristics notes. It must not be soldered or routed on the PCB, as doing so may introduce parasitic capacitance or unintended current paths that degrade regulation stability or ESD performance. The active terminals are pin 1 (anode) and pin 3 (cathode).

What is the maximum reverse leakage current for MMBZ5237ELT1G?

The MMBZ5237ELT1G exhibits ≤0.25 μA reverse leakage current at V_R = 6.5 V and T_A = 25°C, as specified in the Electrical Characteristics table. This ultra-low leakage ensures minimal power loss in battery-critical applications such as always-on sensor nodes or backup power supervisors. Leakage remains below 1 μA up to 85°C per typical curves in Figure 6.

Can MMBZ5237ELT1G be used for transient voltage suppression?

Yes, MMBZ5237ELT1G supports transient suppression with a peak pulse power rating of 225 W for 8 × 20 µs waveforms, validated per Figure 9 of the datasheet. While not a dedicated TVS diode, its fast avalanche response and 16 kV HBM ESD rating make it suitable for low-energy clamping in signal lines and power rails - provided average power remains within 225 mW and pulse repetition is limited to avoid thermal accumulation.