onsemi SZMMBZ9V1ALT3G

Overview

SZMMBZ9V1ALT3G from onsemi is a dual common-anode Zener diode array in SOT-23 package, designed for transient overvoltage and ESD protection of two independent signal lines. It features 9.1 V nominal Zener breakdown voltage (±5%), 14 V clamping voltage at 1.7 A peak pulse current, and 24 W peak pulse power rating per line at 1.0 ms. Used in I/O port protection for microprocessor-based systems including keyboards, printers, and communication interfaces.

For engineers reviewing the SZMMBZ9V1ALT3G datasheet, pinout, applications, or equivalent options, key selection criteria include unidirectional clamping performance, AEC-Q101 qualification for automotive use, bidirectional configuration capability, and compatibility with high-density PCB layouts requiring space-constrained dual-line protection.

Technical Context

This device integrates two monolithic Zener junctions sharing a common anode (Pin 3), enabling independent reverse-biased protection on Pins 1–3 and 2–3. Its 9.1 V nominal breakdown voltage is specified at 1 mA test current with ±5% tolerance and 7.5 mV/°C temperature coefficient.

The dual-diode structure supports both unidirectional (two separate lines) and bidirectional (line-to-line) configurations without external components. It meets IEC 61000-4-2 Level 4 (±30 kV contact discharge) and AEC-Q101 stress requirements for automotive-grade reliability.

Key Specifications

Pinout & Package

SOT-23 (TO-236) package, 2.90 mm × 1.30 mm × 1.00 mm, void-free thermosetting plastic case with UL 94 V-0 flammability rating. Designed for automated placement and reflow soldering at 260 °C for 10 seconds.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-Zener ESD protection applications.

Compared with MMBZ9V1ALT3G and SZMMBZ9V1ALT1G, SZMMBZ9V1ALT3G uniquely combines AEC-Q101 compliance with high-volume 10,000-unit reel packaging - optimizing total cost of ownership for Tier 1 automotive suppliers requiring PPAP traceability and bulk procurement efficiency.

Availability

SZMMBZ9V1ALT3G is available at Aetrix Electronics and suitable for USB interface protection, automotive infotainment I/O, and industrial serial port hardening requiring stable component supply and long-term lifecycle assurance.

Supply support for SZMMBZ9V1ALT3G 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 IoT applications.

SZMMBZxxxALTxG series targets high-reliability transient protection in space-constrained environments, with design focus on AEC-Q101-compliant dual-Zener arrays for automotive electronics and mission-critical industrial interfaces.

FAQ

What is the Zener breakdown voltage tolerance for SZMMBZ9V1ALT3G?

The SZMMBZ9V1ALT3G has a nominal Zener breakdown voltage of 9.1 V with a ±5% tolerance, meaning the actual V_BR falls between 8.65 V and 9.56 V when measured at 1 mA test current. This tight tolerance ensures consistent clamping behavior across production lots and supports reliable 9 V rail protection in precision analog and digital I/O circuits.

Does SZMMBZ9V1ALT3G support bidirectional ESD protection?

Yes, SZMMBZ9V1ALT3G supports bidirectional protection by connecting Pins 1 and 2 together as a differential pair and Pin 3 to ground - forming a symmetrical clamp between the two lines. This configuration meets IEC 61000-4-2 Level 4 for line-to-line ESD events and is commonly used in CAN, RS-485, and USB differential signaling paths.

Is SZMMBZ9V1ALT3G RoHS compliant and halogen-free?

Yes, SZMMBZ9V1ALT3G is Pb-free and RoHS compliant per EU Directive 2011/65/EU. The device uses halogen-free molding compound and meets IPC-4101 definition for "halogen-free" (≤900 ppm bromine, ≤900 ppm chlorine, total ≤1500 ppm). Full material declarations are available via onsemi's Product Compliance Portal.

What is the maximum clamping voltage of SZMMBZ9V1ALT3G under surge conditions?

The maximum clamping voltage (V_C) of SZMMBZ9V1ALT3G is 14 V when subjected to a 1.7 A peak pulse current with a 1.0 ms waveform (Figure 6). This value is guaranteed across temperature and ensures protected ICs experience no more than 14 V during worst-case ESD transients - critical for safeguarding 3.3 V and 5 V logic interfaces.

How does the common-anode architecture of SZMMBZ9V1ALT3G reduce PCB area?

The common-anode architecture of SZMMBZ9V1ALT3G integrates two Zener diodes sharing Pin 3 (anode) in a single SOT-23 package, eliminating the need for two discrete SOT-23 devices and associated routing. This reduces required PCB area by approximately 55% compared to dual-discrete solutions while maintaining independent cathode connections (Pins 1 and 2) for flexible line assignment.