Diodes Incorporated SMF4L45CAQ-7

Overview

SMF4L45CAQ-7 from Diodes Incorporated is a bi-directional transient voltage suppressor (TVS) diode in DO-219AA package, rated for 400W peak pulse power (10/1000µs), 45V working peak reverse voltage (VRWM), 55.3V maximum clamping voltage (VC) at 1A, and 5.5A maximum peak pulse current (IPP). It provides ESD protection per IEC61000-4-2 (±30kV air/contact) and is AEC-Q101 qualified for automotive battery line and power rail protection.

For engineers reviewing the SMF4L45CAQ-7 datasheet, SMF4L45CAQ-7 pinout, SMF4L45CAQ-7 application, or SMF4L45CAQ-7 equivalent, this device is selected for robust overvoltage suppression in space-constrained automotive ECUs, infotainment power inputs, and industrial sensor interface lines where fast response (<5.0ns), low leakage (<0.5µA), and high surge capability are critical.

Technical Context

This bi-directional TVS operates symmetrically across both polarities with a standoff voltage of 45V and clamps transients to ≤72.7V at 5.5A (10/1000µs waveform). Its breakdown voltage is specified at 50–55.3V (min–max) with 1mA test current, ensuring reliable triggering before downstream IC damage.

Thermal design is supported by RθJA = 96°C/W on 1"×1" FR-4 board and RθJC = 18°C/W, enabling stable operation up to +175°C junction temperature. The device exhibits <0.5µA reverse leakage at VRWM and maintains full 400W pulse rating only below +25°C ambient - derating applies per Figure 1.

Key Specifications

Pinout & Package

Package: DO-219AA - surface-mount, ultra-low-profile (height ≤0.75mm), green molded plastic (UL 94V-0), matte tin-plated copper alloy leadframe, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ45CA and TPSMD45C, SMF4L45CAQ-7 offers the lowest profile (DO-219AA), full PPAP capability, and IATF 16949 traceability - making it the preferred choice for next-generation compact automotive electronics requiring certified supply chain continuity.

Availability

SMF4L45CAQ-7 is available at Aetrix Electronics and suitable for automotive battery management, industrial sensor interface protection, and infotainment power rail applications requiring stable component supply, AEC-Q101 compliance, and RoHS 3 environmental certification.

Supply support for SMF4L45CAQ-7 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 sales operations across Asia, Europe, and North America.

The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive power line and interface protection where space, reliability, and regulatory compliance are non-negotiable.

FAQ

What is the maximum clamping voltage of SMF4L45CAQ-7 at its rated peak pulse current?

The maximum clamping voltage (VC) is 72.7V at 5.5A peak pulse current (10/1000µs waveform), measured per IEC 61000-4-5. This value ensures protected downstream components see no more than 72.7V during worst-case surge events, preserving functionality of 40V-rated power stages and interface ICs.

Is SMF4L45CAQ-7 suitable for bidirectional data lines like CAN or LIN?

Yes - its bi-directional architecture and sub-5ns response time make it appropriate for protecting differential bus lines. However, it must be placed on the power rail (VBAT/VCC) side, not directly across signal pairs, as it is not a low-capacitance signal-line TVS. For CAN/LIN signal lines, use dedicated low-C TVS such as D3V3F4U2UP.

Does SMF4L45CAQ-7 require derating at elevated ambient temperatures?

Yes - its 400W peak pulse power rating applies only at TA = +25°C. Derating begins immediately above +25°C per Figure 1 in DS43393 Rev. 3-2, reaching ~50% rating at +100°C ambient. Thermal design must account for PCB copper area, airflow, and adjacent heat sources to maintain effective clamping performance.

How does the DO-219AA package impact PCB layout and thermal performance?

The DO-219AA package measures 2.80 × 1.90 × 0.75 mm and uses a planar leadframe with no exposed thermal pad. Its low height enables placement under connectors or shields, while its RθJA = 96°C/W (on 1"×1" FR-4) requires adequate copper pour and thermal vias beneath the pads to manage steady-state dissipation during repetitive surges.