Diodes Incorporated SMF4L17AQ-7

Overview

SMF4L17AQ from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with 17V working peak reverse voltage (VRWM), 18.9V minimum breakdown voltage (VBR), and 27.6V maximum clamping voltage (VC) at 14.5A peak pulse current. It delivers ±30kV ESD protection per IEC61000-4-2 and is AEC-Q101 qualified for automotive power line and battery contact protection.

For engineers reviewing the SMF4L17AQ datasheet, SMF4L17AQ pinout, SMF4L17AQ application, or SMF4L17AQ equivalent, this device is selected for robust overvoltage suppression in space-constrained automotive ECUs, battery management systems, and 12V/24V power rails where fast response (<1.0ns), low leakage (<0.5μA), and IATF 16949-manufactured reliability are required.

Technical Context

This TVS operates as a unidirectional clamping device, triggered when reverse voltage exceeds 18.9V (min), limiting transient energy to 400W under the standardized 10/1000µs waveform. Its DO-219AA package enables high thermal efficiency with RθJA = 96°C/W on FR-4 PCBs and supports 40A non-repetitive forward surge capability.

Designed for automotive-grade reliability, it features halogen- and antimony-free "Green" molding compound (UL 94V-0), matte tin terminals solderable per MIL-STD-202, and moisture sensitivity level 1 - enabling direct reflow without baking. Polarity is indicated by a cathode band on the top view.

Key Specifications

Pinout & Package

Package: DO-219AA - ultra-compact surface-mount plastic case (1.90mm × 2.80mm × 3.80mm), halogen-free, RoHS-compliant, with cathode band marking polarity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ17A and TPSMA6L17A, SMF4L17AQ offers optimal balance of ultra-compact size, AEC-Q101 compliance, and consistent 27.6V clamping-making it preferred for new automotive designs targeting IATF 16949 traceability and space-constrained layouts.

Availability

SMF4L17AQ is available at Aetrix Electronics and suitable for automotive body electronics, battery management systems, and telematics power protection requiring stable component supply, full AEC-Q101 documentation, and IATF 16949 traceability.

Supply support for SMF4L17AQ 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, specializing in high-reliability protection, power management, and signal integrity solutions for automotive and industrial markets.

The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive power line and interface protection with emphasis on compactness, ESD hardness, and manufacturability in IATF 16949 facilities.

FAQ

Is SMF4L17AQ bidirectional or unidirectional?

SMF4L17AQ is unidirectional, indicated by its cathode band marking. It clamps only reverse-voltage transients on the cathode-connected line while blocking forward current - ideal for protecting positive-rail power inputs. The bi-directional variant is SMF4L17CAQ, which lacks the cathode band and clamps both polarities.

What is the maximum operating temperature for SMF4L17AQ?

SMF4L17AQ has an operating junction temperature range of –55°C to +175°C, validated per AEC-Q101 stress testing. At ambient temperatures above +25°C, its peak pulse power must be derated per Figure 1 in DS43393 - e.g., to ~320W at +85°C ambient - due to thermal limitations of the DO-219AA package.

Does SMF4L17AQ require a heatsink for 400W pulse handling?

No heatsink is required for single-pulse 400W events, as the 10/1000µs waveform delivers energy too briefly for significant thermal accumulation. However, steady-state power dissipation is limited to 1.0W - so continuous DC power must remain below this limit, and repeated pulses require thermal design verification using RθJA = 96°C/W and PCB copper area per Diodes' recommended pad layout.

How does SMF4L17AQ compare to SMAJ17A in PCB assembly?

SMF4L17AQ uses DO-219AA (1.9×2.8mm), while SMAJ17A uses DO-214AC (4.5×2.7mm). The smaller footprint reduces board area by >50% and improves high-frequency surge path inductance. Both are compatible with standard reflow profiles, but DO-219AA's lower mass requires tighter thermal profile control to avoid tombstoning - confirmed in Diodes' packaging guidelines.