Vishay General Semiconductor - Diodes Division SMAJ75A-M3/5A

Overview

SMAJ75A-M3/5A from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode designed for robust overvoltage protection on DC power rails and signal lines. It features a 75 V standoff voltage (V_WM), 83.3–92.1 V breakdown range at 1 mA, clamps transients to ≤121 V at 3.3 A peak pulse current, and delivers 400 W peak pulse power (10/1000 μs waveform) in the SMA (DO-214AC) package - deployed in automotive power supply inputs and industrial sensor interface circuits.

For engineers reviewing the SMAJ75A-M3/5A datasheet, SMAJ75A-M3/5A pinout, SMAJ75A-M3/5A application, or SMAJ75A-M3/5A equivalent, key selection criteria include its unidirectional polarity, 121 V maximum clamping voltage at rated IPPM, 1.0 μA max reverse leakage at 75 V, -55 °C to +150 °C operating junction temperature, and halogen-free RoHS-compliant M3 suffix construction.

Technical Context

This TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents high impedance (<1.0 μA leakage at V_WM = 75 V), but triggers avalanche conduction when transient voltage exceeds V_BR (min 83.3 V, max 92.1 V at 1 mA), limiting downstream voltage to ≤121 V at 3.3 A. Its glass-passivated junction ensures stable breakdown and low incremental surge resistance.

Thermally, it uses the SMA (DO-214AC) surface-mount package with R_θJA = 120 °C/W and R_θJL = 30 °C/W, enabling reliable operation up to T_J = 150 °C. The cathode band identifies polarity, and it meets J-STD-020 MSL Level 1 with 260 °C reflow peak.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102; polarity indicated by cathode band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ75A-E3/5A, the M3 version adds halogen-free compliance without performance trade-offs; versus SMAJ75CA-M3/5A, the unidirectional SMAJ75A-M3/5A offers lower leakage and avoids unnecessary bidirectional conduction in DC systems, improving efficiency and simplifying layout.

Availability

SMAJ75A-M3/5A is available at Aetrix Electronics and suitable for automotive power modules, industrial sensor interfaces, telecom DC feeds, and consumer power adapters requiring stable component supply across production lifecycles.

Supply support for SMAJ75A-M3/5A 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 and automotive qualification.

The SMAJ series is engineered for high-energy transient suppression in harsh environments, targeting ISO 7637-2, IEC 61000-4-2/4-5 compliant designs in automotive, industrial, and telecom infrastructure.

FAQ

What is the maximum clamping voltage of the SMAJ75A-M3/5A under rated surge conditions?

The SMAJ75A-M3/5A clamps to a maximum of 121 V when subjected to its rated peak pulse current of 3.3 A (10/1000 μs waveform). This value is measured per standard test conditions in the Vishay datasheet (Document Number: 88390, Rev. 09-Jan-2024) and defines the upper voltage limit imposed on protected circuitry during transient events. Designers use this parameter to verify that downstream components remain within their absolute maximum ratings.

Does the SMAJ75A-M3/5A meet automotive qualification standards?

The SMAJ75A-M3/5A itself is a commercial-grade part with halogen-free RoHS compliance (M3 suffix), but it is not AEC-Q101 qualified. For automotive applications requiring AEC-Q101, Vishay offers the SMAJ75A-HM3_X variant (e.g., SMAJ75A-HM3_A), which shares identical electrical specs but adds full qualification. Always verify the full ordering code - SMAJ75A-M3/5A is intended for industrial and telecom use where AEC-Q101 is not mandated.

How does the M3 suffix differ from E3 in SMAJ75A-M3/5A?

The M3 suffix in SMAJ75A-M3/5A indicates halogen-free, RoHS-compliant construction, whereas E3 denotes RoHS-compliant but standard brominated flame-retardant molding compound. Both share identical electrical characteristics, thermal performance, and packaging. The M3 version satisfies stricter environmental mandates (e.g., JEDEC J-STD-609 Type II) required in automotive and green-electronics programs, while E3 remains suitable for general commercial applications.

Can SMAJ75A-M3/5A be used in bidirectional signal protection?

No - SMAJ75A-M3/5A is strictly unidirectional and must be oriented with cathode toward the protected line. For bidirectional protection (e.g., AC lines, differential buses like RS-485), the SMAJ75CA-M3/5A variant is required. Using SMAJ75A-M3/5A on bidirectional signals risks forward conduction during negative excursions, causing malfunction or damage. Polarity is marked by a cathode band; bidirectional versions have no marking.

What is the thermal resistance and maximum junction temperature of SMAJ75A-M3/5A?

The SMAJ75A-M3/5A has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead (R_θJL) of 30 °C/W, measured on 0.2" × 0.2" copper pads. Its maximum operating junction temperature is +150 °C, with storage range from -55 °C to +150 °C. These values enable reliable operation in under-hood automotive and industrial enclosures when PCB layout follows Vishay's recommended pad dimensions.