Diodes Incorporated SMAJ7.5CA-13-F

Overview

SMAJ7.5CA-13-F from Diodes Incorporated is a bidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for clamping ESD and surge events on data lines and power rails. It features a 7.5V reverse standoff voltage, 8.33–9.21V breakdown range at 1.0mA test current, 12.9V max clamping voltage at 31.0A peak pulse current, and SMA package with cathode band omitted per bidirectional construction. It is used in automotive infotainment USB ports to protect against IEC 61000-4-2 ±15kV contact discharge.

For engineers reviewing the SMAJ7.5CA-13-F datasheet, SMAJ7.5CA-13-F pinout, SMAJ7.5CA-13-F application, or SMAJ7.5CA-13-F equivalent, key selection criteria include clamping voltage margin relative to system rail, peak pulse current capability under 8.3ms waveform, unidirectional vs. bidirectional polarity requirements, thermal derating above +25°C ambient, and compliance with AEC-Q101 for automotive deployment.

Technical Context

This bidirectional TVS operates symmetrically across both polarities, enabling protection of AC-coupled or differential signal paths without polarity constraints. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<100µA at VRWM), while fast response time (<1ps) limits voltage overshoot during sub-nanosecond transients.

The device sustains 400W non-repetitive peak pulse power per 8.3ms half-sine waveform, with thermal derating to 1.0W steady-state dissipation at TL = +75°C. It meets J-STD-020 moisture sensitivity Level 1 and is RoHS-compliant, halogen-free, and qualified to AEC-Q101 when ordered as SMAJ7.5CAQ variant.

Key Specifications

Pinout & Package

Package: SMA (Surface Mount Assembly), molded plastic case per JEDEC DO-214AC, UL 94V-0 rated, 0.064g typical weight. Cathode band is absent on bidirectional variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ7.5CA-13-F, the unidirectional SMAJ7.5A-13-F demands strict polarity alignment but offers identical surge performance, while the SMBJ7.5CA delivers 50% higher peak power and better thermal endurance at the cost of 40% larger PCB area-making it preferable for mission-critical industrial surge zones.

Availability

SMAJ7.5CA-13-F is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial RS-485 networks, and DC power input protection requiring stable component supply, AEC-Q101-aligned sourcing, and RoHS 3-compliant manufacturing.

Supply support for SMAJ7.5CA-13-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

This device belongs to Diodes' SMAJ series of surface-mount TVS diodes, engineered specifically for high-reliability transient suppression in automotive, industrial, and consumer electronics where compact size, repeatable clamping, and AEC-Q101 qualification are mandatory.

FAQ

What does the "C" suffix in SMAJ7.5CA-13-F indicate?

The "C" denotes bidirectional construction: both terminals behave identically, allowing symmetrical clamping of positive and negative transients. Unlike unidirectional variants (e.g., SMAJ7.5A-13-F), it lacks a cathode band and is used where signal polarity is undefined or alternating, such as RS-485 or AC-coupled audio lines.

Is SMAJ7.5CA-13-F qualified for automotive use?

The standard SMAJ7.5CA-13-F is not AEC-Q101 qualified; however, Diodes offers the automotive-grade SMAJ7.5CAQ-13-F variant-identical electrically but manufactured in IATF 16949-certified facilities, with PPAP documentation and extended reliability testing per AEC-Q101 Rev D.

How does clamping voltage relate to system protection margin?

With a max clamping voltage of 12.9V at 31.0A, this TVS holds protected circuits below that threshold during surge events. For a 12V nominal rail, this provides ~0.9V margin above nominal-sufficient to prevent overvoltage damage to 13.5V-absolutes-rated ICs, assuming proper PCB layout and minimal trace inductance.

Can SMAJ7.5CA-13-F replace SMAJ6.5CA-13-F in an existing design?

Only if the system's maximum operating voltage and transient immunity requirements align with the higher 7.5V standoff. SMAJ6.5CA has lower VRWM (6.5V) and clamps at 11.2V; substituting SMAJ7.5CA raises the clamping floor by 1.7V, potentially exposing downstream ICs to unsafe voltages during marginal overvoltage conditions.