Vishay General Semiconductor - Diodes Division SMCJ17CAHM3_A/H

Overview

SMCJ17CAHM3_A/H from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for high-energy surge protection. It features a 17 V standoff voltage (VWM), 1500 W peak pulse power rating (10/1000 µs), and clamps transients to ≤27.6 V at 54.3 A peak pulse current - deployed across automotive sensor signal lines, industrial I/O ports, and telecom interface protection.

For engineers reviewing the SMCJ17CAHM3_A/H datasheet, SMCJ17CAHM3_A/H pinout, SMCJ17CAHM3_A/H application, or SMCJ17CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, halogen-free RoHS compliance, and compatibility with automated SMT assembly on 8 mm × 8 mm copper pads.

Technical Context

This device operates as a voltage-clamping protector using an avalanche breakdown mechanism. Its bidirectional structure enables symmetrical transient suppression in AC-coupled or floating signal paths without polarity sensitivity. The glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 µA at VWM).

Thermal performance is defined by R_θJA = 75 °C/W (typ.) and R_θJL = 15 °C/W (typ.), supporting reliable operation up to T_J = +150 °C. It meets MSL Level 1 per J-STD-020 with peak reflow temperature of 260 °C, and is qualified to AEC-Q101 for automotive under-hood applications.

Key Specifications

Pinout & Package

SMCJ17CAHM3_A/H uses the SMC (DO-214AB) package: a two-terminal, non-polarized surface-mount case with matte tin-plated leads solderable per J-STD-002. Bidirectional construction means no cathode/anode marking; both terminals are functionally identical.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ17CAHM3_A/H, SMAJ17CAHE3_A/H offers reduced surge handling in a smaller footprint, while SMCJ17CA-E3/57T provides identical protection without AEC-Q101 or halogen-free certification - making the HM3 variant uniquely suited for automotive-tier production with full environmental compliance.

Availability

SMCJ17CAHM3_A/H is available at Aetrix Electronics and suitable for automotive sensor protection, industrial RS-485 interface hardening, and telecom line card surge suppression requiring stable component supply across multi-year production cycles.

Supply support for SMCJ17CAHM3_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, rectifiers, MOSFETs, and protection devices with emphasis on reliability, precision, and application-specific optimization.

The SMCJ series targets high-energy transient suppression in harsh environments, with design focus on automotive, industrial, and telecom infrastructure where robustness, AEC-Q101 validation, and repeatable clamping performance are critical.

FAQ

What does the "HM3" suffix indicate in SMCJ17CAHM3_A/H?

The "HM3" suffix in SMCJ17CAHM3_A/H denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It confirms compliance with automotive reliability standards and environmental regulations, distinguishing it from commercial-grade variants like SMCJ17CA-E3/57T. This makes SMCJ17CAHM3_A/H suitable for under-hood and safety-critical applications where material content and long-term stability are mandated.

Is SMCJ17CAHM3_A/H unidirectional or bidirectional?

SMCJ17CAHM3_A/H is a bidirectional TVS diode, as indicated by the "CA" suffix in its part number. It provides symmetrical clamping in both polarities, eliminating the need for polarity-aware placement on PCBs. This is essential for protecting AC-coupled, differential, or floating signal paths such as RS-485, CAN, or telecom line interfaces where voltage transients can swing positive or negative relative to ground.

What is the maximum clamping voltage of SMCJ17CAHM3_A/H at rated surge current?

The maximum clamping voltage (V_C) of SMCJ17CAHM3_A/H is 27.6 V at 54.3 A peak pulse current (I_PPM) under the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that downstream circuitry sees no more than 27.6 V during a full-rated surge event - a critical parameter for ensuring compatibility with 3.3 V, 5 V, or 12 V interface ICs.

Can SMCJ17CAHM3_A/H be used in place of a unidirectional SMCJ17A variant?

No - SMCJ17CAHM3_A/H is not a drop-in replacement for unidirectional SMCJ17A. While both share the same VWM (17 V) and package, the CA version lacks polarity marking and delivers symmetrical clamping, whereas the unidirectional variant requires correct cathode orientation and only clamps in reverse bias. Substituting them without verifying circuit topology may result in improper protection or forward conduction during normal operation.

What PCB layout guidance applies to SMCJ17CAHM3_A/H for optimal thermal and surge performance?

For optimal performance, mount SMCJ17CAHM3_A/H on minimum 0.31" × 0.31" (8.0 mm × 8.0 mm) copper pads per terminal, as specified in the Vishay datasheet. Use short, wide traces to minimize inductance, and avoid vias near terminals. Thermal relief should be minimized to maximize heat dissipation, since R_θJA is rated at 75 °C/W under this pad configuration - critical for sustaining repeated surge events without junction overheating.