Diodes Incorporated SMBJ33A-13-F

Overview

SMBJ33A-13-F from Diodes Incorporated is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode with 33V reverse standoff voltage, 36.7V minimum breakdown voltage at 1mA, and 53.3V maximum clamping voltage at 11.3A peak pulse current. It features glass-passivated die construction, SMB package, and is rated for industrial power supply input protection against ESD and lightning-induced surges.

For engineers reviewing the SMBJ33A-13-F datasheet, SMBJ33A-13-F pinout, SMBJ33A-13-F application, or SMBJ33A-13-F equivalent, key selection criteria include clamping voltage margin relative to protected IC V_BR, peak pulse current capability under 8.3ms half-sine waveform, thermal derating above +25°C, and RoHS-compliant matte tin lead finish for lead-free reflow compatibility.

Technical Context

This TVS diode operates as a shunt-clamping device in parallel with sensitive circuitry, activating when transient voltage exceeds its reverse standoff rating (33V) and clamping to ≤53.3V at 11.3A. Its glass-passivated junction ensures stable leakage (<5μA at VRWM) and repeatable breakdown behavior across temperature.

The SMB package enables high-power dissipation (600W non-repetitive) in a compact footprint, with thermal resistance from junction-to-lead of ~20°C/W and operating junction temperature range from –55°C to +150°C - critical for automotive and industrial environments where ambient temperatures exceed 85°C.

Key Specifications

Pinout & Package

Package: SMB (Surface Mount Body), molded plastic case per UL 94V-0, 0.1g weight, 3.30–3.94mm (A) × 4.06–4.57mm (B) × 1.96–2.21mm (C) dimensions. Cathode band denotes polarity for unidirectional operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ33AHE3/5BT, the SMBJ33A-13-F lacks AEC-Q200 qualification but offers identical electrical protection in a standard commercial-grade part; versus 1.5SMC33A, it trades thermal robustness for 40% smaller PCB area - critical for dense industrial modules.

Availability

SMBJ33A-13-F is available at Aetrix Electronics and suitable for industrial power supply input protection, automotive body control module (BCM) auxiliary rail protection, and factory automation PLC digital input protection requiring stable component supply and full traceability.

Supply support for SMBJ33A-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 centers across Asia and manufacturing facilities in China, Taiwan, and the U.S.

The SMBJ series belongs to Diodes' transient voltage suppression portfolio, engineered specifically for high-energy surge protection in industrial, automotive, and telecom infrastructure where reliability under harsh electrical stress is non-negotiable.

FAQ

What is the maximum clamping voltage of SMBJ33A-13-F at its rated peak pulse current?

The maximum clamping voltage (V_C) is 53.3V at 11.3A peak pulse current (I_PP), measured using an 8.3ms half-sine waveform per IEC 61000-4-5. This value is guaranteed across the full operating temperature range (–55°C to +150°C) and defines the upper voltage limit imposed on protected circuitry during surge events.

Is SMBJ33A-13-F suitable for bidirectional signal line protection?

No - SMBJ33A-13-F is a unidirectional TVS diode, indicated by the absence of "C" in its part number. It conducts only when cathode voltage exceeds anode voltage by ≥36.7V. For bidirectional protection (e.g., RS-485, USB D+/D–), the bi-directional variant SMBJ33CA-13-F must be used, which clamps symmetrically for both polarities.

How does the SMB package affect thermal performance compared to SMA or SMC?

The SMB package has lower thermal resistance than SMA (junction-to-lead R_θJL ≈ 20°C/W vs ~25°C/W) but higher than SMC (~15°C/W). Its 0.1g mass and 4.6mm × 3.6mm footprint enable faster heat dissipation than SMA while maintaining compact size - ideal for space-constrained industrial modules where 600W surge handling is required without forced airflow.

Does SMBJ33A-13-F require derating for operation above +25°C ambient?

Yes - peak pulse power must be linearly derated above +25°C at 4.8W/°C, per datasheet Figure 1. At +75°C ambient, maximum allowable P_PK drops to 360W. This derating applies to single-pulse conditions; repetitive surges require additional duty cycle reduction to prevent junction overheating beyond 150°C.