Vishay General Semiconductor - Diodes Division SMAJ75CA001HE3_A/I

Overview

SMAJ75CA001HE3_A/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 75 V standoff voltage (V_WM), 83.3–92.1 V breakdown voltage (V_BR) at 1 mA, 121 V maximum clamping voltage (V_C) at 3.3 A peak pulse current, and 400 W peak pulse power rating (10/1000 μs waveform). It is AEC-Q101 qualified and used to protect MOSFETs, ICs, and sensor signal lines in automotive power systems.

For engineers reviewing the SMAJ75CA001HE3_A/I datasheet, SMAJ75CA001HE3_A/I pinout, SMAJ75CA001HE3_A/I application, or SMAJ75CA001HE3_A/I equivalent, key selection criteria include bidirectional clamping capability, 121 V clamping at 3.3 A, AEC-Q101 qualification, RoHS-compliant matte tin terminations, and compatibility with automated SMT placement on standard PCB pad layouts.

Technical Context

This device operates as a voltage-clamping protector: under normal conditions it presents high impedance (>1 μA leakage at 75 V), but during transients exceeding V_BR, it avalanches rapidly to limit voltage across protected circuitry. Its bidirectional symmetry enables use on AC-coupled or floating lines without polarity concerns.

Thermal performance is defined by R_θJA = 120 °C/W (on 0.2" × 0.2" copper pads) and R_θJL = 30 °C/W, supporting reliable operation up to T_J = +150 °C. The glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repetitive surge stress.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. No polarity marking for bidirectional types.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ75CA001HE3_A/I, SMAJ75CA-E3/61 offers identical clamping performance at lower cost but lacks automotive qualification, while SMBJ75CAHE3_A/I delivers 50 % higher surge power in a physically larger package - enabling trade-offs between reliability assurance, cost, and energy-handling headroom.

Availability

SMAJ75CA001HE3_A/I is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interfaces, consumer power adapter protection, and telecom line card surge suppression requiring stable component supply and AEC-Q101 traceability.

Supply support for SMAJ75CA001HE3_A/I 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, surge endurance, and qualification compliance are mandatory.

FAQ

What is the clamping voltage of SMAJ75CA001HE3_A/I at its rated peak pulse current?

The SMAJ75CA001HE3_A/I has a maximum clamping voltage (V_C) of 121 V at 3.3 A peak pulse current (I_PPM) under the standard 10/1000 μs waveform. This value is measured per JEDEC test conditions and defines the upper voltage limit imposed on protected circuitry during surge events. The 121 V clamping ensures compatibility with 100 V-rated downstream components in 12 V and 24 V automotive and industrial systems.

Is SMAJ75CA001HE3_A/I suitable for automotive applications?

Yes, SMAJ75CA001HE3_A/I is AEC-Q101 qualified, with full test documentation covering HTGB, H3TRB, TC, and surge endurance per automotive reliability standards. Its RoHS-compliant matte tin terminations, MSL Level 1 rating, and guaranteed operation from –55 °C to +150 °C make SMAJ75CA001HE3_A/I appropriate for engine control units, body electronics, and ADAS power domains.

How does the bidirectional design of SMAJ75CA001HE3_A/I affect its circuit implementation?

The bidirectional architecture of SMAJ75CA001HE3_A/I eliminates polarity constraints - it clamps equally for positive and negative transients across its terminals. This allows direct placement on AC-coupled lines, transformer secondaries, or floating sensor outputs without orientation checks. Unlike unidirectional TVS diodes, SMAJ75CA001HE3_A/I requires no cathode band alignment, reducing assembly errors and simplifying PCB layout for differential or symmetric protection schemes.

What is the thermal resistance of SMAJ75CA001HE3_A/I, and how does it impact PCB layout?

SMAJ75CA001HE3_A/I 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. To maintain T_J ≤ 150 °C under worst-case 3.3 W steady-state dissipation, designers must ensure adequate copper area and avoid thermal bottlenecks. Reducing pad size or omitting thermal vias increases R_θJA, risking premature thermal shutdown or parametric shift during sustained surge duty cycles.

Does SMAJ75CA001HE3_A/I have a specified junction capacitance, and why does it matter?

While not explicitly tabulated for SMAJ75CA001HE3_A/I in the provided datasheet, the SMAJ family exhibits typical junction capacitance of ≈100 pF at 0 V (per Fig. 4, extrapolated from adjacent V_WM values). This capacitance impacts high-frequency signal integrity - for example, in CAN or RS-485 lines, excessive C_J can attenuate edges or cause timing jitter. The 100 pF level is acceptable for <10 Mbps digital interfaces but may require filtering or layout mitigation above 50 MHz analog paths.