STMicroelectronics LFTVS18-1F3

Overview

LFTVS18-1F3 from STMicroelectronics is a unidirectional low-forward-voltage Transil™ transient voltage suppressor diode designed for ESD and EOS protection of high-speed data lines in portable electronics. It features 16 V breakdown voltage (V_BR), 19 V clamping voltage at 1 A (V_CL), 175 pF junction capacitance at 0 V, 1.3 V forward voltage at 850 mA, and complies with IEC 61000-4-2 Level 4 (±15 kV air / ±8 kV contact discharge).

For engineers reviewing the LFTVS18-1F3 datasheet, LFTVS18-1F3 pinout, LFTVS18-1F3 application, or LFTVS18-1F3 equivalent, key selection criteria include clamping factor (V_CL/V_BR = 1.19), ultra-thin flip-chip package footprint (0.77 mm × 0.77 mm), low dynamic impedance, and line-capacitance-sensitive interface protection for USB 2.0, HDMI, and audio jack circuits.

Technical Context

The LFTVS18-1F3 employs a silicon avalanche diode structure optimized for fast response (<1 ns) and minimal parasitic capacitance. Its unidirectional configuration provides asymmetric clamping-low forward conduction (1.3 V @ 850 mA) for signal integrity during normal operation and robust reverse avalanche clamping (19 V @ 1 A) during transients.

Designed for flip-chip mounting with four solder bumps (A1, A2, B1, B2), it integrates directly onto PCB traces without wire bonds, minimizing inductance and preserving high-frequency ESD immunity. The 400 µm pitch and 185 µm bump height enable fine-pitch routing in space-constrained mobile designs.

Key Specifications

Pinout & Package

Package: Flip-chip (4-bump), 0.77 mm × 0.77 mm body, 400 µm pitch, RoHS-compliant ECOPACK® grade.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ18A and ESD5Z7.0T1G, the LFTVS18-1F3 uniquely balances 16 V standoff, 19 V clamping, 175 pF capacitance, and flip-chip integration-making it optimal for miniaturized, high-speed interfaces where layout inductance and board area are limiting factors.

Availability

LFTVS18-1F3 is available at Aetrix Electronics and suitable for USB 2.0 interface protection, HDMI hot-plug detection, and wearable sensor bus hardening requiring stable component supply across production lifecycles.

Supply support for LFTVS18-1F3 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.

The Transil™ TVS portfolio targets system-level ESD/EOS protection with emphasis on low-clamp, low-capacitance, and ultra-compact packaging for portable and IoT edge devices.

FAQ

What is the recommended PCB layout for LFTVS18-1F3 to maintain ESD performance?

Place the device within 3 mm of the protected connector with symmetric, short (<2 mm), equal-length traces to A1/A2 and B1/B2. Use dedicated ground vias under B1/B2 bumps and avoid routing other signals beneath the device. Follow ST's AN2348 footprint recommendations: 220 µm solder mask opening and 300 µm × 300 µm stencil aperture for reliable reflow.

Does LFTVS18-1F3 support bidirectional transient suppression?

No-it is a unidirectional device optimized for clamping positive transients on signal-to-ground paths. For bidirectional protection (e.g., USB D+/D−), two devices must be used back-to-back, or a dedicated bidirectional TVS like SMF18A should be selected instead.

How does the 400 µm pitch affect assembly yield in high-volume manufacturing?

The 400 µm pitch is compatible with standard SMT placement equipment (±25 µm accuracy) and reflow profiles. ST's ECOPACK® qualification and tape-and-reel packaging (10,000 units per reel) ensure >99.95% first-pass yield when using recommended stencil design and nitrogen reflow. No special placement tooling is required.

Can LFTVS18-1F3 replace older Transil™ parts like SMBJ18A in legacy designs?

Only with layout revision: LFTVS18-1F3's flip-chip form factor and 0.77 mm footprint differ fundamentally from SMBJ18A's DO-214AA package. Electrical substitution is valid (same V_BR, higher P_PP, lower V_CL), but mechanical redesign is mandatory due to incompatible mounting and thermal path.