Diodes Incorporated SMF4L8.0AQ-7

Overview

SMF4L8.0AQ from Diodes Incorporated is a unidirectional transient voltage suppressor (TVS) diode designed for robust overvoltage protection in automotive and industrial power rails. It features a 8.0 V working peak reverse voltage (VRWM), 8.89–9.83 V breakdown voltage (VBR) at 1 mA, 13.6 V maximum clamping voltage (VC) at 29.4 A peak pulse current, and 400 W peak pulse power dissipation (10/1000 µs waveform). It is AEC-Q101 qualified and used on battery feed lines and ECU power inputs.

For engineers reviewing the SMF4L8.0AQ datasheet, SMF4L8.0AQ pinout, SMF4L8.0AQ application, or SMF4L8.0AQ equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD tolerance, IEC 61000-4-2 ±30 kV ESD capability, DO-219AA package thermal performance, and AEC-Q101 qualification status for automotive deployment.

Technical Context

This TVS operates as a unidirectional clamp between power rail and ground, activating when transient voltage exceeds its breakdown threshold. Its fast response time (<1.0 ns from 0 V to VBR) ensures protection before downstream ICs experience overstress. The device uses silicon avalanche junction technology with low dynamic impedance to maintain tight clamping under high surge currents.

Thermal design relies on its DO-219AA package's low RθJA (96 °C/W) and RθJC (18 °C/W), enabling effective heat transfer to PCB copper. It supports continuous DC power dissipation up to 1.0 W at +25°C, derating linearly above that temperature per Figure 1 and Figure 3 in DS43393 Rev. 3-2.

Key Specifications

Pinout & Package

Package: DO-219AA - Surface-mount, flat lead, cathode-banded unidirectional configuration; 1.90 mm width × 2.80 mm length × 0.60 mm height; matte tin-plated copper alloy leads; RoHS-compliant, halogen-free "Green" molding compound (UL 94V-0).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TVS diode applications.

Compared with SMAJ8.0A and TPSMA6L8.0A, SMF4L8.0AQ delivers superior power density (400 W in DO-219AA), tighter thermal resistance, and verified AEC-Q101 process control-making it the preferred choice for next-generation compact automotive ECUs requiring both space efficiency and full ISO 7637-2 compliance.

Availability

SMF4L8.0AQ is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power inputs, and smart sensor node protection requiring stable component supply across extended temperature ranges (−55°C to +175°C) and long product lifecycles.

Supply support for SMF4L8.0AQ 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, manufacturing, and distribution operations across Asia, Europe, and North America.

The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive-grade transient suppression in harsh environments-emphasizing low clamping voltage, high surge robustness, and zero-defect manufacturing for safety-critical systems.

FAQ

What is the polarity configuration of SMF4L8.0AQ?

SMF4L8.0AQ is a unidirectional TVS diode, indicated by a cathode band on the DO-219AA package. It conducts only when the anode is more positive than the cathode, making it suitable for DC power rail protection where reverse voltage is not expected. This differs from bi-directional variants (e.g., SMF4L8.0CAQ) which protect AC or bidirectional signal lines.

How does SMF4L8.0AQ perform under high ambient temperatures?

At +125°C ambient, SMF4L8.0AQ retains ~65% of its 400 W peak pulse power rating due to thermal derating per Figure 1 in DS43393. Its RθJA of 96 °C/W allows effective heat sinking via 2 oz. copper pads, and its −55°C to +175°C operating range supports under-hood automotive placement without derating concerns for steady-state operation.

Is SMF4L8.0AQ compatible with lead-free reflow processes?

Yes-SMF4L8.0AQ features a matte tin finish on annealed copper alloy leads and is rated for standard lead-free reflow profiles (JEDEC J-STD-020, peak 260°C). Its moisture sensitivity level is MSL 1, meaning it can be stored indefinitely at ≤30°C/60% RH without baking prior to assembly, simplifying SMT line logistics.

Can SMF4L8.0AQ replace older SMAJ8.0A devices in existing designs?

Yes, with layout adaptation: SMF4L8.0AQ uses DO-219AA (1.90 × 2.80 mm), while SMAJ8.0A uses DO-214AC (4.3 × 2.6 mm). Electrical specs align closely (same VRWM, VBR, VC, and IPP), but SMF4L8.0AQ offers lower thermal resistance and 30% smaller footprint-requiring pad redesign but delivering improved power density and automotive qualification assurance.