Diodes Incorporated SMAJ9.0A-13

Overview

SMAJ9.0A-13 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for primary overvoltage protection in DC power lines and signal interfaces. It features a 9.0V reverse standoff voltage, 10.0–11.1V breakdown at 1.0mA test current, 15.4V max clamping voltage at 26.0A peak pulse current, and operates from –55°C to +150°C - deployed in automotive body control modules to protect CAN transceiver I/O against ISO 7637-2 load dump surges.

For engineers reviewing the SMAJ9.0A-13 datasheet, SMAJ9.0A-13 pinout, SMAJ9.0A-13 application, or SMAJ9.0A-13 equivalent, key selection criteria include clamping voltage margin vs. protected IC V_DD, peak pulse current capability under 8.3ms half-sine surge, unidirectional polarity alignment with supply rail topology, and SMA package thermal performance under sustained ambient conditions up to +125°C.

Technical Context

This TVS diode uses a glass-passivated silicon junction optimized for fast response (<1 ps) to transient events, with clamping action triggered when reverse voltage exceeds the 10.0V minimum breakdown threshold. Its unidirectional configuration provides low-leakage (<5.0 µA @ 9.0V) blocking in normal operation while enabling robust 400W peak pulse power dissipation during ESD or surge events.

The device complies with JEDEC-standard 8.3ms single half-sine waveform testing (IFSM = 40A), and its steady-state power rating is 1.0W at TL = 75°C. Thermal derating follows a defined curve down to zero power at +175°C lead temperature, supporting placement near heat-generating components in compact PCB layouts.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, molded plastic case with UL 94V-0 flammability rating, cathode band polarity indicator, and 0.064g typical weight.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ9.0CA-13 and P6SMB9.0A-13-F, the SMAJ9.0A-13 delivers optimal balance of compact SMA footprint, precise 9.0V standoff, and verified 26A/15.4V clamping performance for cost-sensitive, volume automotive and industrial DC rail protection.

Availability

SMAJ9.0A-13 is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, and telecom power supplies requiring stable component supply, RoHS compliance, and consistent surge performance across production batches.

Supply support for SMAJ9.0A-13 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, specializing in high-reliability protection, power management, and signal integrity solutions for automotive, industrial, and consumer markets.

The SMAJ series belongs to Diodes' transient voltage suppressor product line, engineered specifically for robust, standardized overvoltage protection in harsh-environment applications where predictable clamping behavior and JEDEC-compliant surge endurance are mandatory.

FAQ

What is the polarity configuration of SMAJ9.0A-13?

SMAJ9.0A-13 is a unidirectional TVS diode with cathode-band marking. It conducts only during reverse-biased transients - i.e., when the cathode is driven positive relative to the anode. This configuration ensures minimal leakage on positive DC rails and prevents unintended conduction during normal operation.

Can SMAJ9.0A-13 be used in place of a bidirectional TVS?

No - SMAJ9.0A-13 is not interchangeable with bidirectional devices like SMAJ9.0CA-13. Using it on AC-coupled or floating lines risks failure during negative transients, as it lacks reverse conduction capability. Bidirectional replacement requires matching VRWM, PPK, and package, with explicit validation of clamping symmetry.

What is the maximum allowable PCB trace length between SMAJ9.0A-13 and the protected IC?

To maintain effective clamping, the combined trace inductance from TVS anode to ground plane and cathode to protected node must remain below ~10 nH. For SMAJ9.0A-13, this typically means total trace length ≤15 mm with solid ground plane underneath - longer paths increase voltage overshoot due to L·di/dt during fast transients.

Does SMAJ9.0A-13 require derating at elevated ambient temperatures?

Yes - its peak pulse power must be derated linearly above TA = 25°C per Figure 1 in DS19005. At +85°C ambient, usable PPK drops to ~70% (280W); at +125°C, it falls to ~40% (160W). Designers must verify clamping voltage remains within safe margins under worst-case thermal and surge conditions.