Alpha & Omega Semiconductor Inc. SMDJ15CA

Overview

SMDJ15CA from Alpha & Omega Semiconductor is a bi-directional transient voltage suppressor diode in DO-214AB (SMC) package, designed for robust ESD and surge protection in DC power rails and signal lines. It features 15.0 V reverse stand-off voltage (VRWM), 16.7–18.5 V breakdown voltage (VBR @ 1 mA), 24.4 V maximum clamping voltage at 123 A peak pulse current, and 3000 W peak pulse power rating on 10/1000 µs waveform.

For engineers reviewing the SMDJ15CA datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping capability, low leakage (<2.0 µA @ VRWM), fast response time (<1.0 ps), JEDEC-compliant DO-214AB surface-mount packaging, and compatibility with automated reflow assembly per J-STD-020 MSL Level 1.

Technical Context

The SMDJ15CA operates as a voltage-clamped avalanche diode, leveraging a glass-passivated junction to achieve stable, repeatable breakdown behavior under transient stress. Its bi-directional polarity enables symmetrical clamping across both polarities without external circuit inversion, supporting protection of AC-coupled or floating interfaces.

Thermal performance is defined by R_θJL = 15 °C/W (junction-to-lead) and R_θJA = 75 °C/W (junction-to-ambient, on 8.0 mm × 8.0 mm copper pads), enabling reliable operation up to T_J = 150 °C. The device sustains non-repetitive 8.3 ms half-sine surges up to 300 A and meets UL 94V-0 flammability requirements.

Key Specifications

Pinout & Package

DO-214AB (SMC) package: molded plastic case with J-bend leads; cathode identified by color band (not applicable for bi-directional types like SMDJ15CA); terminals solderable per MIL-STD-750 Method 2026; RoHS and halogen-free compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC15CA and P6SMB15CA, the SMDJ15CA delivers tighter VBR tolerance (±5.4% vs ±6.7%), lower leakage (<2.0 µA vs 5.0 µA), and superior thermal resistance (R_θJL = 15 °C/W), making it preferred for high-reliability, thermally constrained designs.

Availability

SMDJ15CA is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, and telecom power feeds requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for SMDJ15CA 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

Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, TVS diodes, and power ICs for computing, consumer, industrial, and automotive markets.

The SMDJ series is engineered specifically for high-power transient suppression in harsh environments, emphasizing robustness, tight parametric control, and JEDEC-standardized packaging for automated manufacturing.

FAQ

What is the clamping voltage of the SMDJ15CA under a 10/1000 µs surge?

The SMDJ15CA exhibits a maximum clamping voltage (V_C) of 24.4 V when subjected to its rated peak pulse current of 123 A on a 10/1000 µs waveform. This value is measured per industry standard test conditions and defines the upper voltage limit imposed on protected circuitry during surge events. The SMDJ15CA maintains this clamping performance across its full operating temperature range and lifetime, supported by its glass-passivated junction structure.

Is the SMDJ15CA suitable for bidirectional signal line protection?

Yes, the SMDJ15CA is explicitly designed for bidirectional transient suppression, as indicated by the "CA" suffix and confirmed in the datasheet's "Devices for Bipolar Application" section. Its symmetrical breakdown characteristics allow it to clamp equally during positive and negative voltage excursions, making it ideal for protecting AC-coupled interfaces such as RS-485, CAN, or audio lines without polarity concerns. The SMDJ15CA does not require external biasing or orientation-specific placement.

What is the maximum steady-state power dissipation of the SMDJ15CA?

The SMDJ15CA is not rated for continuous power dissipation; it is a transient suppression device intended for short-duration, non-repetitive surges. Its steady-state power handling is negligible - typical leakage current is <2.0 µA at 15.0 V VRWM, resulting in <30 µW static power loss. Any sustained forward or reverse bias above V_BR will cause thermal runaway. The SMDJ15CA must be used exclusively within its specified transient ratings and derated per ambient temperature curves.

Does the SMDJ15CA meet automotive AEC-Q200 requirements?

No, the SMDJ15CA is not AEC-Q200 qualified. While it operates from –55 °C to +150 °C and supports automotive-relevant surge levels (e.g., ISO 7637-2 Pulse 5a), Alpha & Omega Semiconductor does not list AEC-Q200 qualification for the SMDJ family in its official documentation or product change notices. For AEC-Q200-compliant alternatives, engineers should consider AOS's AQ series or consult Aetrix Electronics for validated automotive-grade TVS options.

What is the thermal resistance from junction to ambient for the SMDJ15CA?

The SMDJ15CA has a typical junction-to-ambient thermal resistance (R_θJA) of 75 °C/W when mounted on 8.0 mm × 8.0 mm copper pads per terminal, as specified in the Absolute Maximum Ratings table. This value assumes standard JEDEC test conditions and is critical for estimating junction temperature rise during repetitive surge events. For accurate thermal modeling, designers must also account for R_θJL = 15 °C/W and PCB copper area, layer count, and airflow - the SMDJ15CA's thermal performance is highly layout-dependent.