Vishay General Semiconductor - Diodes Division SMAJ150CA-M3/5A

Overview

SMAJ150CA-M3/5A from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 150 V stand-off voltage (VWM), 167–185 V breakdown voltage (VBR) at 1 mA, 243 V maximum clamping voltage (VC) at 1.2 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform). It protects MOSFETs, ICs, and sensor interfaces in industrial and automotive electronics.

For engineers reviewing the SMAJ150CA-M3/5A datasheet, SMAJ150CA-M3/5A pinout, SMAJ150CA-M3/5A application, or SMAJ150CA-M3/5A equivalent, key selection criteria include bidirectional clamping capability, 150 V stand-off rating, 243 V clamping under 1.2 A surge, SMA package thermal resistance (RθJA = 120 °C/W), and halogen-free RoHS compliance per M3 suffix.

Technical Context

This device operates as a voltage-clamping protector with symmetrical avalanche breakdown in both directions, enabling use on AC lines or ungrounded differential signals without polarity concerns. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 μA at VWM).

Rated for 400 W peak pulse power (10/1000 μs) up to 78 V and 300 W above - confirmed at 150 V - it delivers repeatable transient suppression under repetitive surges at ≤0.01% duty cycle. Thermal performance is defined by RθJA = 120 °C/W (on 0.2" × 0.2" copper pads) and TJ max = 150 °C.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads; meets UL 94 V-0, J-STD-002 solderability, and JESD 201 Class 2 whisker resistance. Bidirectional configuration has no polarity marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ150CA-M3/5A, the E3 variant offers identical clamping and thermal performance with relaxed material compliance, while the unidirectional SMAJ150A-M3/5A introduces polarity dependency and lacks symmetrical surge response - making the original bidirectional M3 part optimal for noise-immune, layout-flexible protection in mixed-signal systems.

Availability

SMAJ150CA-M3/5A is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and telecom power supply inputs requiring stable component supply, halogen-free compliance, and AEC-Q101-qualified reliability.

Supply support for SMAJ150CA-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, efficiency, and application-specific optimization.

The SMAJ series targets board-level transient protection in space-constrained, high-reliability applications - engineered for fast response, low clamping, and robust surge handling across automotive, industrial, and telecom end markets.

FAQ

What is the clamping voltage of SMAJ150CA-M3/5A at its rated peak pulse current?

The SMAJ150CA-M3/5A exhibits a maximum clamping voltage (VC) of 243 V when subjected to its specified peak pulse current (IPPM) of 1.2 A under the 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during transient events. The SMAJ150CA-M3/5A maintains this clamping performance across its full operating temperature range.

Is SMAJ150CA-M3/5A suitable for automotive applications?

Yes, SMAJ150CA-M3/5A is qualified to AEC-Q101 when ordered with HE3 or HM3 suffixes; however, the M3/5A variant itself is commercial-grade and not AEC-Q101 certified. For automotive use, specify SMAJ150CA-HM3/5A to ensure qualification. The SMAJ150CA-M3/5A retains the same electrical and thermal specs but lacks formal automotive stress testing documentation.

What does the "CA" suffix indicate in SMAJ150CA-M3/5A?

The "CA" suffix in SMAJ150CA-M3/5A denotes bidirectional functionality - meaning the device provides symmetrical transient suppression in both polarities without requiring orientation during placement. Unlike unidirectional "A" variants (e.g., SMAJ150A), the CA version has no cathode band marking and supports AC-coupled or floating signal line protection. This is explicitly confirmed in Vishay's documentation for all CA-suffixed SMAJ devices.

How does the thermal resistance of SMAJ150CA-M3/5A affect PCB layout?

SMAJ150CA-M3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe operation at full 3.3 W steady-state dissipation or repeated surges, designers must allocate adequate copper area and avoid thermally isolating the SMA pads. Reducing RθJA via larger thermal pads or internal planes directly extends surge endurance and lifetime reliability of the SMAJ150CA-M3/5A.

What is the maximum reverse leakage current for SMAJ150CA-M3/5A at its stand-off voltage?

The maximum reverse leakage current (ID) for SMAJ150CA-M3/5A is 1.0 μA when biased at its 150 V stand-off voltage (VWM), tested at TA = 25 °C. This ultra-low leakage ensures minimal power loss and signal distortion in high-impedance or battery-powered circuits. The SMAJ150CA-M3/5A maintains this specification across its full −55 °C to +150 °C operating junction temperature range, with leakage increasing predictably per datasheet derating curves.