Taiwan Semiconductor Corporation SMDJ17CA

Overview

SMDJ17CA from Taiwan Semiconductor is a bidirectional 3000W surface-mount transient voltage suppressor (TVS) diode with a working stand-off voltage of 17 V, breakdown voltage range of 18.9–20.9 V, and clamping voltage of 27.6 V at 108.7 A peak pulse current. It is designed for ESD and surge protection in DC power rails and signal lines of industrial control systems, telecom interfaces, and automotive ECUs.

For engineers reviewing the SMDJ17CA datasheet, SMDJ17CA pinout, SMDJ17CA application, or SMDJ17CA equivalent, key selection criteria include its DO-214AB (SMC) package compatibility, bidirectional polarity, 175 °C maximum junction temperature, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive transients.

Technical Context

The SMDJ17CA operates as a bidirectional avalanche diode, clamping transient overvoltages in both forward and reverse directions without requiring external biasing. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at 17 V), while its sub-1 ps response time enables effective suppression of fast-rising ESD events per IEC 61000-4-2.

Thermally, it features a junction-to-lead resistance of 15 °C/W and junction-to-ambient resistance of 75 °C/W, supporting reliable operation under repetitive surge conditions when mounted on adequate copper area. It is rated for 300 A non-repetitive forward surge (8.3 ms half-sine) and operates across –55 °C to +175 °C.

Key Specifications

Pinout & Package

DO-214AB (SMC) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band (not functional in bidirectional SMDJ17CA); weight ≈ 0.290 g; UL 94V-0 rated compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC17CA and 1.5KE18CA, the SMDJ17CA delivers full 3000 W surge capability in an automated-placement-ready SMC package, making it the preferred choice for production-grade automotive and industrial systems requiring robust, scalable transient immunity.

Availability

SMDJ17CA is available at Aetrix Electronics and suitable for automotive power line protection, industrial Ethernet port hardening, telecom DC input safeguarding, and PLC I/O module surge resilience requiring stable component supply and full ISO 7637-2 compliance.

Supply support for SMDJ17CA 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for industrial and automotive markets.

The SMDJ series was developed specifically for high-power, surface-mount transient suppression in harsh environments-emphasizing reliability under repeated surge stress, thermal robustness, and compliance with automotive EMC standards.

FAQ

What is the maximum clamping voltage of the SMDJ17CA under a 3000 W transient?

The SMDJ17CA clamps to a maximum of 27.6 V when subjected to its rated peak pulse current of 108.7 A (10/1000 µs waveform), corresponding to 3000 W. This value is measured per IEC 61000-4-5 and guarantees downstream circuit protection within safe voltage margins. The SMDJ17CA maintains this clamping performance across its full operating temperature range of –55 °C to +175 °C.

Is the SMDJ17CA unidirectional or bidirectional, and how does that affect PCB layout?

The SMDJ17CA is a bidirectional TVS diode, indicated by the "CA" suffix, meaning it provides symmetrical clamping in both polarities without requiring orientation-specific placement. Unlike unidirectional variants (e.g., SMDJ17A), the SMDJ17CA has no cathode marking and can be mounted in either direction across protected lines. This simplifies PCB layout and eliminates polarity-check steps during automated assembly.

Does the SMDJ17CA meet automotive transient immunity standards?

Yes, the SMDJ17CA meets ISO 7637-2 requirements for Pulses 1, 2a, 2b, 3a, and 3b-covering typical automotive transients such as load dump, relay switching, and ignition noise. It is not rated for Pulse 5a (load dump with suppression network), which demands higher energy handling; for that, the SMDJ17CA must be used with external impedance coordination. The SMDJ17CA's 3000 W rating supports robust Pulse 5a mitigation when properly applied.

What is the thermal resistance and recommended PCB layout for full-power operation of the SMDJ17CA?

The SMDJ17CA has a junction-to-lead thermal resistance (R_θJL) of 15 °C/W and junction-to-ambient (R_θJA) of 75 °C/W. To sustain full 3000 W pulse capability, each lead must connect to ≥100 mm² of 2-ounce copper on the PCB, with thermal vias to inner or backside planes. The SMDJ17CA's DO-214AB package relies on copper area-not just trace width-for heat spreading during transient events.

Can the SMDJ17CA replace the SMDJ17A in an existing design?

Yes, the SMDJ17CA is a direct physical and electrical replacement for the unidirectional SMDJ17A in most applications, sharing identical DO-214AB packaging, pinout, and thermal characteristics. However, because the SMDJ17CA is bidirectional, it will conduct during negative transients where the SMDJ17A would block-so verify system-level polarity tolerance before substitution. The SMDJ17CA's leakage and clamping behavior remain consistent in both directions.