Vishay General Semiconductor - Diodes Division SMAJ22A-E3/61

Overview

SMAJ22A-E3/61 from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for robust overvoltage protection on power and signal lines. It features a 22 V standoff voltage (V_WM), 24.4–26.9 V breakdown voltage (V_BR) at 1 mA, clamps transients to ≤35.5 V at 11.3 A peak pulse current, and delivers 400 W peak pulse power (10/1000 μs waveform). It is widely deployed in automotive ECUs, industrial sensor interfaces, and DC power rails to suppress ESD and inductive switching surges.

For engineers reviewing the SMAJ22A-E3/61 datasheet, SMAJ22A-E3/61 pinout, SMAJ22A-E3/61 application, or SMAJ22A-E3/61 equivalent, key selection criteria include its unidirectional polarity, SMA (DO-214AC) package compatibility with automated SMT assembly, low clamping ratio (VC/V_BR ≈ 1.38), and AEC-Q101 qualification readiness via HE3 suffix variants.

Technical Context

This TVS diode operates as a clamping device-conducting only when reverse voltage exceeds V_BR, thereby limiting transient energy across protected circuitry. Its glass-passivated junction ensures stable leakage (<1.0 μA at 22 V) and fast response time (<1.0 ps), critical for sub-nanosecond ESD events per IEC 61000-4-2.

The device uses a single-junction PN structure optimized for low incremental surge resistance (r_d ≈ 2.1 Ω derived from ΔV_C/ΔI_PPM), enabling effective suppression without significant voltage overshoot. Thermal performance is defined by R_θJA = 120 °C/W (on 0.2" × 0.2" copper pads), supporting continuous operation up to T_J = 150 °C.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002. Cathode indicated by band; anode is unmarked end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ22A-E3/61, the M3 variant adds halogen-free compliance without altering performance, while the HE3 variant adds AEC-Q101 qualification-making it suitable for automotive applications where reliability validation is mandatory, whereas the E3 version serves commercial/industrial use cases with standard RoHS compliance.

Availability

SMAJ22A-E3/61 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and DC-DC converter input surge suppression requiring stable component supply and full traceability.

Supply support for SMAJ22A-E3/61 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, rectifiers, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.

The SMAJ series is engineered for high-energy transient suppression in space-constrained, high-reliability applications-including automotive, industrial controls, and telecom infrastructure-where fast clamping and repeatable surge endurance are critical.

FAQ

What is the maximum clamping voltage of the SMAJ22A-E3/61 under standard test conditions?

The SMAJ22A-E3/61 has a maximum clamping voltage (V_C) of 35.5 V when subjected to its rated peak pulse current of 11.3 A using the 10/1000 μs waveform. This value is measured per JEDEC standards and ensures predictable voltage limiting during surge events, directly protecting downstream components such as 24 V-rated microcontrollers and gate drivers in the SMAJ22A-E3/61 application circuit.

Is the SMAJ22A-E3/61 suitable for automotive applications?

The SMAJ22A-E3/61 itself is commercial-grade and RoHS-compliant but not AEC-Q101 qualified. However, Vishay offers the pin-compatible SMAJ22AHE3_A/H variant-identical in electrical and mechanical specifications-which is fully AEC-Q101 qualified. For automotive use, designers should specify the HE3 suffix version; the SMAJ22A-E3/61 remains appropriate for non-automotive industrial or consumer applications where qualification is not required.

What does the "-E3/61" suffix indicate in SMAJ22A-E3/61?

The "-E3" suffix denotes RoHS-compliant, commercial-grade construction with matte tin-plated leads, while "/61" specifies packaging in 7-inch plastic tape-and-reel format with a base quantity of 1800 units. This ordering code ensures compatibility with standard SMT pick-and-place equipment and simplifies inventory management for high-volume production of boards using the SMAJ22A-E3/61.

How does the SMAJ22A-E3/61 compare to bidirectional TVS diodes like SMAJ22CA?

The SMAJ22A-E3/61 is unidirectional and intended for DC line protection where polarity is fixed (e.g., +24 V rail to ground), offering lower leakage and tighter V_BR tolerance. In contrast, SMAJ22CA is bidirectional and suited for AC or differential signal lines (e.g., RS-485, CAN). They share identical V_WM, V_BR, and P_PPM, but the SMAJ22A-E3/61 cannot replace SMAJ22CA in symmetrical surge environments without circuit redesign.

What PCB layout guidance applies to the SMAJ22A-E3/61 for optimal thermal and electrical performance?

Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad for each terminal of the SMAJ22A-E3/61 to achieve rated P_PPM and R_θJA = 120 °C/W. Short, wide traces to ground minimize inductance and preserve clamping speed; avoid thermal relief on pads to maximize heat dissipation. The SMAJ22A-E3/61 must be placed as close as possible to the protected port, with ground connections routed directly to a solid ground plane.