Vishay General Semiconductor - Diodes Division SMAJ30AHE3_A/H

Overview

SMAJ30AHE3_A/H from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode designed for robust overvoltage protection of sensitive electronics. It features a 30 V standoff voltage (VWM), 33.3–36.8 V breakdown voltage (VBR) at 1 mA, 48.4 V maximum clamping voltage (VC) at 8.3 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.

For engineers reviewing the SMAJ30AHE3_A/H datasheet, SMAJ30AHE3_A/H pinout, SMAJ30AHE3_A/H application, or SMAJ30AHE3_A/H equivalent, key selection criteria include clamping performance under 8.3 A surge, unidirectional polarity marking, AEC-Q101 qualification status, SMA (DO-214AC) package thermal resistance (RθJA = 120 °C/W), and compliance with UL 497B for protector classification.

Technical Context

This TVS diode operates as a fast-acting shunt clamp during transient events, leveraging a glass-passivated silicon junction to achieve sub-nanosecond response time. Its unidirectional configuration provides reverse-biased protection only, with cathode band marking and forward voltage drop of 3.5 V at 25 A (IF).

The device is rated for repetitive 10/1000 μs surges at 0.01 % duty cycle (400 W ≤ 78 V; 300 W > 78 V), derated above 25 °C per Fig. 2, and supports operation from –55 °C to +150 °C junction temperature. It meets JESD201 Class 2 whisker resistance and MSL Level 1 reflow profile (260 °C peak).

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), molded case with matte tin-plated leads, polarity indicated by cathode band on unidirectional types. Mounting requires 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal per datasheet Fig. 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ30A-E3/61, SMAJ30AHE3_A/H adds AEC-Q101 qualification for automotive deployment; compared with SMAJ30CAHE3_A/H, it provides polarity-defined clamping for DC rail protection but requires correct orientation during placement.

Availability

SMAJ30AHE3_A/H is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interface protection, and telecom power input staging requiring stable component supply with full traceability and lifecycle continuity.

Supply support for SMAJ30AHE3_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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and application-specific performance.

The SMAJ series is engineered for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom systems where robustness against ISO 7637, IEC 61000-4-2/4/5, and load-dump events is mandatory.

FAQ

What is the clamping voltage of SMAJ30AHE3_A/H at its rated peak pulse current?

The SMAJ30AHE3_A/H has a maximum clamping voltage (VC) of 48.4 V at 8.3 A peak pulse current (IPPM), measured under the standardized 10/1000 μs waveform. This value defines the upper voltage limit imposed on protected circuitry during surge events and is confirmed in the Electrical Characteristics table on page 2 of Vishay document 88390. The SMAJ30AHE3_A/H maintains this clamping performance across its qualified operating temperature range.

Is SMAJ30AHE3_A/H suitable for automotive applications?

Yes, SMAJ30AHE3_A/H is AEC-Q101 qualified, as explicitly stated in the Mechanical Data section and Ordering Information table of Vishay document 88390. The "HE3" suffix denotes RoHS-compliant and AEC-Q101 qualified construction, making SMAJ30AHE3_A/H appropriate for automotive body control modules, infotainment power supplies, and sensor interfaces where qualification to this stress-test standard is required.

What does the "_A/H" suffix in SMAJ30AHE3_A/H indicate?

The "_A/H" suffix in SMAJ30AHE3_A/H specifies the packaging configuration: "H" denotes 7-inch diameter plastic tape and reel with 1800 units per reel, while "A" indicates the revision code per Vishay's ordering convention. This matches the preferred package code "H" and base quantity "1800" shown in the Ordering Information table on page 3 of document 88390. The suffix does not affect electrical or thermal specifications of the SMAJ30AHE3_A/H device itself.

How does SMAJ30AHE3_A/H differ from bidirectional TVS diodes like SMAJ30CAHE3_A/H?

SMAJ30AHE3_A/H is unidirectional, with a cathode band marking and asymmetric conduction: it clamps only in reverse bias (protecting positive transients on a DC line referenced to ground). In contrast, SMAJ30CAHE3_A/H is bidirectional, offering symmetrical clamping for AC signals or floating lines. Both share identical VWM (30 V), VBR (33.3–36.8 V), and VC (48.4 V), but SMAJ30AHE3_A/H must be oriented correctly during PCB placement, whereas SMAJ30CAHE3_A/H has no polarity marking.

What thermal design considerations apply to SMAJ30AHE3_A/H?

SMAJ30AHE3_A/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To sustain repetitive surges, ensure adequate PCB copper area and avoid thermal bottlenecks near the SMAJ30AHE3_A/H body. Its RθJL is 30 °C/W, indicating efficient heat transfer to solder joints - critical for maintaining TJ ≤ 150 °C during high-duty-cycle transients.