Vishay General Semiconductor - Diodes Division SMBJ22A-M3/5B

Overview

SMBJ22A-M3/5B from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in the SMB (DO-214AA) package, designed for robust overvoltage protection of sensitive electronics. It features a 22 V stand-off voltage (V_WM), 24.4–26.9 V breakdown voltage (V_BR) at 1 mA, 35.5 V maximum clamping voltage (V_C) at 16.9 A peak pulse current, and 600 W peak pulse power rating with 10/1000 µs waveform - deployed on power rails and signal lines in industrial motor drives.

For engineers reviewing the SMBJ22A-M3/5B datasheet, SMBJ22A-M3/5B pinout, SMBJ22A-M3/5B application, or SMBJ22A-M3/5B equivalent, key selection criteria include clamping performance under 16.9 A surge, thermal resistance (R_θJA = 100 °C/W), halogen-free RoHS compliance (M3 suffix), and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.

Technical Context

This TVS diode operates as a unidirectional avalanche clamp, leveraging a glass-passivated silicon junction to deliver sub-nanosecond response to transients induced by inductive switching or ESD events. Its cathode-band polarity marking enables unambiguous orientation during PCB layout, and it meets J-STD-020 MSL Level 1 with 260 °C reflow peak tolerance.

The device sustains repetitive 600 W pulses at 0.01 % duty cycle and derates linearly above 25 °C ambient per Fig. 2; its 1.0 µA max reverse leakage at V_WM ensures minimal standby power loss in always-on circuits such as sensor front-ends or CAN bus terminations.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, unidirectional polarity marked by cathode band. Terminals are matte tin-plated, solderable per J-STD-002 and JESD 22-B102.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with SMBJ22A-E3/5B, the M3 variant adds halogen-free assurance without sacrificing clamping or thermal performance; versus SAC22, SMBJ22A-M3/5B provides 50 % higher surge power handling and 8 V lower clamping - critical for protecting 24 V power domains.

Availability

SMBJ22A-M3/5B is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom power supplies, and consumer appliance control boards requiring stable component supply with halogen-free compliance and MSL Level 1 assembly support.

Supply support for SMBJ22A-M3/5B 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, power efficiency, and automotive qualification.

The SMBJ series was engineered for high-energy transient suppression in harsh environments - targeting industrial automation, transportation, and infrastructure systems where failure resilience and long-term parametric stability are mandatory.

FAQ

What is the maximum clamping voltage of SMBJ22A-M3/5B under standard test conditions?

The SMBJ22A-M3/5B has a maximum clamping voltage (V_C) of 35.5 V when subjected to a 10/1000 µs surge current pulse of 16.9 A. This value is measured per IEC 61000-4-5 and defines the upper voltage limit imposed on protected circuitry during transient events - a critical parameter for ensuring downstream 24 V ICs remain within absolute maximum ratings. The SMBJ22A-M3/5B maintains this clamping performance across its full operating temperature range.

Does SMBJ22A-M3/5B meet automotive qualification standards?

The SMBJ22A-M3/5B itself is commercial-grade and halogen-free (M3 suffix), but Vishay offers AEC-Q101-qualified versions in the same SMBJ22A family under ordering codes like SMBJ22AHM3_B/I. These qualified variants share identical electrical characteristics and package dimensions with SMBJ22A-M3/5B but undergo extended stress testing per AEC-Q101. For automotive use, specify the HM3_X suffix variant rather than SMBJ22A-M3/5B.

What is the thermal resistance of SMBJ22A-M3/5B, and how does it affect PCB layout?

The SMBJ22A-M3/5B has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes minimum recommended pad layout per Vishay's datasheet Figure 6. To maintain safe junction temperatures under repetitive surges, designers must allocate adequate copper area and avoid excessive trace length between the SMBJ22A-M3/5B and ground/power planes - undersized pads will elevate R_θJA and risk thermal runaway.

How does the M3 suffix differ from E3 in SMBJ22A-M3/5B?

The M3 suffix in SMBJ22A-M3/5B indicates halogen-free, RoHS-compliant construction using bromine- and chlorine-free molding compounds, whereas E3 denotes RoHS-compliant but non-halogen-free materials. Both meet JEDEC J-STD-020 MSL Level 1 and share identical electrical parameters, package dimensions, and thermal performance. The M3 variant satisfies stricter environmental mandates such as IPC-1752A Class I and certain Tier 1 automotive material declarations - making SMBJ22A-M3/5B appropriate where halogen-free content is contractually required.

Can SMBJ22A-M3/5B be used for bidirectional transient protection?

No - SMBJ22A-M3/5B is a unidirectional TVS diode, identifiable by its cathode band marking. For bidirectional protection, Vishay specifies the SMBJ22CA variant (e.g., SMBJ22CA-M3/5B), which exhibits symmetrical clamping in both polarities and no polarity marking. Using SMBJ22A-M3/5B in AC-coupled or floating signal paths risks forward conduction during negative transients, potentially damaging the device or failing to protect the circuit. Always match device polarity to system grounding architecture.