Vishay General Semiconductor - Diodes Division SMAJ22CAHE3_A/H

Overview

SMAJ22CAHE3_A/H 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 signal and power lines. It features a 22 V standoff voltage (V_WM), 24.4–26.9 V breakdown voltage (V_BR) at 1 mA, 35.5 V maximum clamping voltage (V_C) at 11.3 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial control systems.

For engineers reviewing the SMAJ22CAHE3_A/H datasheet, SMAJ22CAHE3_A/H pinout, SMAJ22CAHE3_A/H application, or SMAJ22CAHE3_A/H equivalent, this device is selected for robust ESD and surge protection where bidirectional clamping, AEC-Q101 qualification, low incremental surge resistance, and MSL Level 1 reflow compatibility are required.

Technical Context

This bidirectional TVS operates symmetrically across both polarities, delivering identical clamping behavior in forward and reverse directions. Its glass-passivated junction ensures stable breakdown characteristics and fast response time (<1 ps), while the SMA package supports automated placement and meets UL 94 V-0 flammability requirements.

The device is rated for 400 W peak pulse power (10/1000 μs) up to 78 V, derating to 300 W above that threshold. With a thermal resistance of 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), it sustains repetitive surge events under defined PCB pad layout conditions (0.2" × 0.2" copper pads per terminal).

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking. Case dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); matte tin-plated leads compliant with J-STD-002 and JESD 22-B102.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ22CA-M3/61, SMAJ22CAHE3_A/H offers identical protection performance with standard RoHS compliance; compared with SMCJ22CAHE3_A/H, it trades lower surge capacity for 55 % smaller footprint - critical for compact ECUs and sensor nodes where board area is premium.

Availability

SMAJ22CAHE3_A/H is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC analog inputs, consumer USB peripherals, and telecom Ethernet PHY protection requiring stable component supply and AEC-Q101 assurance.

Supply support for SMAJ22CAHE3_A/H 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 is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where consistent clamping, low leakage, and reflow compatibility are non-negotiable.

FAQ

What does the "CA" suffix indicate in SMAJ22CAHE3_A/H?

The "CA" suffix denotes a bidirectional configuration, meaning SMAJ22CAHE3_A/H provides symmetrical clamping in both forward and reverse directions. Unlike unidirectional variants (e.g., SMAJ22A), it has no cathode marking and is used where polarity of transient events is undefined - such as across AC signal lines, transformer windings, or differential buses. This eliminates need for orientation verification during placement.

Is SMAJ22CAHE3_A/H qualified for automotive applications?

Yes, SMAJ22CAHE3_A/H is AEC-Q101 qualified, verified per stress tests including high-temperature reverse bias (HTRB), temperature cycling, and ESD (HBM ≥8 kV). Its construction - glass-passivated junction, MSL Level 1 rating, and -55 °C to +150 °C operating range - meets requirements for under-hood and cabin-mounted automotive electronics, including body control units and ADAS sensors.

How does the clamping voltage of SMAJ22CAHE3_A/H compare to its standoff voltage?

SMAJ22CAHE3_A/H has a 22 V standoff voltage (V_WM) and a maximum clamping voltage (V_C) of 35.5 V at 11.3 A. This 13.5 V differential represents the voltage "window" across which the device transitions from high-impedance blocking to low-impedance conduction. That margin ensures protected ICs see no more than 35.5 V during surge, well below typical 40 V absolute maximum ratings of 3.3 V/5 V logic interfaces.

Can SMAJ22CAHE3_A/H replace SMAJ22A in an existing design?

No - SMAJ22CAHE3_A/H is bidirectional while SMAJ22A is unidirectional, with a cathode band indicating polarity. Substituting SMAJ22CAHE3_A/H for SMAJ22A removes polarity dependency but alters circuit behavior: it will conduct during negative transients where SMAJ22A would block. Redesign review is required to confirm whether bidirectional clamping aligns with system grounding and signal swing requirements.

What is the thermal resistance of SMAJ22CAHE3_A/H, and how does it affect layout?

SMAJ22CAHE3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead (R_θJL) of 30 °C/W. To maintain safe operation under repetitive surges, PCB layout must use minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. Smaller pads increase thermal impedance, risking junction overheating and premature failure during sustained transient activity.