STMicroelectronics SMP75-8

Overview

SMP75-8 from STMicroelectronics is a bidirectional Trisil™ transient voltage surge suppressor (TVSS) designed for primary-level overvoltage protection in telecom line interfaces. It features 8 V breakover voltage, ≤2 µA leakage at 6 V, 150 mA minimum holding current, 75 A repetitive peak pulse current (10/1000 µs), and SMB (DO-214AA) surface-mount package. It protects low-voltage Ethernet and T1/E1 transformer-coupled circuits without core saturation.

For engineers reviewing the SMP75-8 datasheet, SMP75-8 pinout, SMP75-8 application, or SMP75-8 equivalent, key selection criteria include bidirectional crowbar behavior, fail-safe short-circuit mode under overcurrent, compliance with GR-1089 Core, ITU-T K20/K21, IEC 61000-4-5, and UL94 V0 resin certification - all critical for telecom surge protection design validation.

Technical Context

The SMP75-8 operates as a voltage-triggered silicon bilateral switch that latches into low-impedance conduction upon exceeding its 8 V dynamic breakover voltage (VBO), sustaining conduction until current falls below 150 mA holding threshold (IH). Its bidirectional crowbar action provides symmetrical clamping for AC-coupled telecom lines.

It meets stringent telecom surge standards including GR-1089 Core (first-level 2500 V/500 A), ITU-T K20 (6 kV/150 A), and IEC 61000-4-5 (4 kV/100 A), supported by thermal robustness (Tj max = 150 °C) and fail-safe short-circuit failure mode under sustained overcurrent.

Key Specifications

Pinout & Package

The SMP75-8 is housed in an SMB (JEDEC DO-214AA) surface-mount package with molded UL94 V0 epoxy and lead-free terminations. The device is bidirectional and symmetrical; both terminals serve identical roles in surge conduction path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar telecom surge protection applications.

Compared with SMP75-8, SPA1004 requires polarity-aware layout and offers higher clamping, while V18MLA0603 lacks fail-safe behavior and introduces signal integrity risk via higher capacitance - making SMP75-8 uniquely suited for primary, standards-compliant telecom line protection where reliability and symmetry are mandatory.

Availability

SMP75-8 is available at Aetrix Electronics and suitable for Ethernet physical layer protection, T1/E1 line interface protection, and DSLAM front-end surge protection requiring stable component supply and long-term lifecycle support.

Supply support for SMP75-8 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, specializing in power management, analog, MEMS, and automotive-grade ICs with strong emphasis on industrial and communications infrastructure.

The Trisil™ product line was developed specifically for telecom-grade surge protection, delivering fail-safe crowbar behavior, GR-1089/ITU-T compliance, and long-term stability in harsh line-interface environments.

FAQ

What is the fail-safe behavior of SMP75-8 during end-of-life?

The SMP75-8 enters a permanent short-circuit state under sustained overcurrent, ensuring continued surge shunting even after repeated stress. This fail-safe mode prevents open-circuit failure that could expose downstream circuitry to unclamped transients - a critical requirement for telecom central office equipment certified to GR-1089 Core.

Can SMP75-8 be used in DC-powered Ethernet (PoE) applications?

Yes - its 8 V breakover voltage and ≤2 µA leakage at 6 V allow safe integration into PoE-enabled 10/100/1000BASE-T interfaces. It must be placed upstream of the PoE injector splitter and isolated from DC bias using coupling capacitors or transformers to avoid unintended triggering during normal 48 V DC operation.

How does SMP75-8 compare to gas discharge tubes (GDTs) in telecom protection?

SMP75-8 offers faster response (<100 ns vs. ~100–500 ns for GDTs), lower capacitance (60 pF vs. 1–2 pF but with higher parasitic inductance), and no follow-current limitation. Unlike GDTs, it does not require series impedance to quench arc, enabling simpler, more compact front-end protection layouts compliant with ITU-T K21.

Is SMP75-8 compatible with lead-free reflow soldering processes?

Yes - the SMB package is lead-free and qualified for JEDEC J-STD-020D reflow profiles, with maximum lead temperature rated at 260 °C for 10 seconds. Its UL94 V0 epoxy and thermal resistance (Rth(j-a) = 100 °C/W) ensure reliability under standard Pb-free assembly conditions without delamination or parameter shift.