Vishay General Semiconductor - Diodes Division SMAJ26A-M3/61

Overview

SMAJ26A-M3/61 from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for primary overvoltage protection of DC power rails and signal lines. It features a 26 V standoff voltage (V_WM), 28.9–31.9 V breakdown range at 1 mA, clamps transients to ≤42.1 V at 9.5 A peak pulse current, and delivers 400 W peak pulse power (10/1000 μs waveform). It is used in automotive body control modules to protect 24 V CAN transceivers against load dump and inductive switching surges.

For engineers reviewing the SMAJ26A-M3/61 datasheet, SMAJ26A-M3/61 pinout, SMAJ26A-M3/61 application, or SMAJ26A-M3/61 equivalent, key selection criteria include unidirectional polarity, SMA (DO-214AC) package compatibility with automated SMT assembly, AEC-Q101 qualification status, clamping voltage under surge conditions, and thermal resistance (R_θJA = 120 °C/W).

Technical Context

This TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents high impedance (>1 μA leakage at 26 V), but triggers into low-impedance conduction when reverse voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable avalanche characteristics and fast response (<1 ns) to ESD and lightning-induced transients.

The device is rated for repetitive 10/1000 μs surges at 0.01% duty cycle (400 W up to 78 V; derated to 300 W above), mounted on 5.0 mm × 5.0 mm copper pads. Its M3 suffix confirms halogen-free, RoHS-compliant construction with matte tin-plated leads meeting J-STD-002 solderability and JESD201 Class 2 whisker resistance.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, single-ended unidirectional configuration with cathode band marking. Dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H), compliant with IPC-7351B SOIC127P10X35X40.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ26A-M3/61, the E3 variant offers identical protection performance at lower material cost for non-automotive applications, while the HM3 variant adds AEC-Q101 validation and process controls essential for functional safety-critical vehicle subsystems - neither is pin-compatible without verifying qualification scope and material declarations.

Availability

SMAJ26A-M3/61 is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, telecom power systems, and consumer appliance designs requiring stable component supply with halogen-free compliance and SMT placement support.

Supply support for SMAJ26A-M3/61 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, MOSFETs, optoelectronics, and passive components with emphasis on reliability, efficiency, and application-specific optimization.

The SMAJ series was developed for high-energy transient suppression in space-constrained, high-reliability applications - particularly targeting automotive, industrial, and telecom markets where standardized DO-214AC packaging and predictable clamping behavior are critical.

FAQ

What is the maximum clamping voltage of the SMAJ26A-M3/61 under a 10/1000 μs surge?

The SMAJ26A-M3/61 clamps to a maximum of 42.1 V when subjected to its rated peak pulse current of 9.5 A (10/1000 μs waveform). This value is measured per IEC 61000-4-5 test conditions and defines the upper voltage limit imposed on protected circuitry during surge events. The clamping voltage remains stable across temperature and lifetime when operated within specified derating curves.

Is the SMAJ26A-M3/61 AEC-Q101 qualified?

No, the SMAJ26A-M3/61 is a commercial-grade part with halogen-free and RoHS-compliant construction (M3 suffix), but it is not AEC-Q101 qualified. For automotive applications requiring formal qualification, the SMAJ26AHM3/61 variant is available - it shares identical electrical and mechanical specifications but includes full AEC-Q101 stress testing, lot traceability, and automotive-specific documentation.

What does the "/61" in SMAJ26A-M3/61 indicate?

The "/61" suffix in SMAJ26A-M3/61 denotes the preferred packaging format: 7-inch diameter plastic tape and reel containing 1800 units. This format is optimized for high-speed pick-and-place assembly and aligns with industry-standard EIA-481-D carrier tape specifications. Other options include "/5A" (13-inch reel, 7500 units) and automotive variants with "/H" or "/I" codes.

Can SMAJ26A-M3/61 be used in bidirectional protection circuits?

No, SMAJ26A-M3/61 is a unidirectional TVS diode and must be used with correct polarity - cathode connected to the protected line, anode to ground. For bidirectional protection, the SMAJ26CA-M3/61 variant is required, which provides symmetrical clamping in both directions and has no polarity marking. Using SMAJ26A-M3/61 in reverse-biased configurations risks permanent failure due to forward conduction during negative transients.

What is the thermal resistance and how does it affect layout design for SMAJ26A-M3/61?

The SMAJ26A-M3/61 has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes minimal copper area; increasing pad size or adding thermal vias reduces R_θJA and improves surge endurance. Layouts for high-duty-cycle applications should allocate ≥100 mm² of 2-oz copper per terminal and avoid narrow traces between the device and ground plane.