onsemi SZMMBZ27VCWT1G

Overview

SZMMBZ27VCWT1G from onsemi is a dual common-cathode Zener transient voltage suppression (TVS) diode in SC−70 package, rated for 40 W peak pulse power at 1.0 ms, 27 V nominal breakdown voltage, and 22 V working peak reverse voltage. It provides bidirectional ESD protection exceeding 16 kV HBM and <100 nA leakage at VRWM, used for line-level surge protection in automotive single-wire CAN networks and I/O interfaces.

For engineers reviewing the SZMMBZ27VCWT1G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage (38 V @ 1.0 A), dual-line common-cathode topology, SC−70 footprint constraints, AEC−Q101 qualification, and bidirectional TVS capability for ESD-prone signal lines.

Technical Context

This device implements a monolithic dual-junction Zener structure with shared cathode (Pins 1 & 2 = anodes, Pin 3 = common cathode), enabling either two independent unidirectional clamps or one bidirectional clamp across a single line pair. Its thermal resistance (R_JA = 618°C/W) and FR−5 board derating profile support transient handling without sustained thermal runaway.

The 27 V nominal Zener voltage exhibits ±5% tolerance (25.65–28.35 V) and a positive temperature coefficient (~26 mV/°C), ensuring stable clamping over −55°C to +150°C junction range. Clamping occurs at 38 V under 1.0 A peak pulse current per Figure 4 waveform, with forward voltage ≤1.1 V at 200 mA.

Key Specifications

Pinout & Package

SC−70 (SOT−323) package with void-free thermosetting plastic case, UL 94 V−0 flammability rating, and Pb−free/Halogen−free construction. Maximum soldering temperature: 260°C for 10 seconds.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SZMMBZ27VCWT1G, SZMMBZ27VCWT3G offers identical protection performance with higher reel quantity for manufacturing scale, while MMBZ27VCWT1G provides matching electrical behavior without automotive qualification-enabling trade-offs between compliance assurance and unit cost.

Availability

SZMMBZ27VCWT1G is available at Aetrix Electronics and suitable for automotive ECU design, industrial serial interface hardening, and medical I/O port protection requiring stable component supply and AEC−Q101 validation.

Supply support for SZMMBZ27VCWT1G 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and logic solutions for automotive, industrial, and cloud infrastructure markets.

SZMMBZ27VCWT1G belongs to the MMBZ27VCW family of dual Zener TVS diodes engineered specifically for compact, high-reliability transient suppression in automotive and medical electronics where space, ESD robustness, and qualification rigor are critical.

FAQ

What is the clamping voltage of SZMMBZ27VCWT1G under a 1.0 A transient pulse?

The clamping voltage of SZMMBZ27VCWT1G is 38 V when subjected to a 1.0 A peak pulse current with a 1.0 ms duration per the Figure 4 waveform in the datasheet. This value represents the maximum voltage imposed on the protected line during the surge event and is measured across Pins 1–3 or 2–3 in unidirectional configuration. The 38 V clamping ensures downstream components remain within safe operating limits during typical ESD or inductive switching events.

Is SZMMBZ27VCWT1G suitable for bidirectional signal line protection?

Yes, SZMMBZ27VCWT1G supports bidirectional protection by connecting the common cathode (Pin 3) to ground and using both anodes (Pins 1 and 2) on opposite sides of a differential or single-ended line. In this configuration, it functions as a symmetrical TVS with 27 V breakdown in both directions, delivering 40 W peak pulse power per polarity. Its dual-anode/common-cathode architecture inherently enables this mode without external components.

Does SZMMBZ27VCWT1G meet automotive qualification standards?

Yes, SZMMBZ27VCWT1G is AEC−Q101 qualified and PPAP capable, confirming its suitability for automotive applications including engine control units, body electronics, and infotainment systems. The "SZ" prefix denotes compliance with automotive-specific site controls, change management, and traceability requirements beyond standard commercial-grade MMBZ27VCWT1G devices.

What is the maximum allowable leakage current for SZMMBZ27VCWT1G at its working voltage?

The maximum reverse leakage current for SZMMBZ27VCWT1G is 100 nA when biased at its working peak reverse voltage of 22 V, measured at 25°C ambient temperature. This low leakage ensures minimal impact on signal integrity and power budget in always-on or low-power circuits such as sensor interfaces and battery-backed systems where standby current must be tightly controlled.

How does the SC−70 package of SZMMBZ27VCWT1G compare to SOD-323 in layout terms?

The SC−70 package used by SZMMBZ27VCWT1G is identical to SOT−323 and mechanically interchangeable with SOD-323 footprints, measuring 2.2 mm × 1.35 mm × 0.95 mm with 0.65 mm lead pitch. However, SC−70 specifies tighter mold compound tolerances and void-free construction per onsemi's mechanical outline CASE 419, ensuring consistent thermal performance and solder joint reliability in automated assembly processes.