STMicroelectronics SMP100LC-35

Overview

SMP100LC-35 from STMicroelectronics is a bidirectional thyristor surge suppressor (TSS) designed for fail-safe overvoltage protection on telecom and industrial data lines. It features a 35 V breakover voltage (V_BO), 100 A repetitive peak pulse current (10/1000 µs), 55 pF capacitance at 2 V, ≤32 µA leakage current at 35 V, and 150 mA minimum holding current - enabling robust protection of xDSL/Ethernet line cards without signal distortion.

For engineers reviewing the SMP100LC-35 datasheet, SMP100LC-35 pinout, SMP100LC-35 application, or SMP100LC-35 equivalent, this device is selected for high-speed data line surge protection where low capacitance, fail-safe short-circuit behavior, and compliance with GR-1089 Core, ITU-T K20/K21, and IEC 61000-4-5 are mandatory.

Technical Context

The SMP100LC-35 operates as a voltage-triggered bidirectional crowbar device: it remains high-impedance until reverse or forward voltage exceeds its static breakover threshold (~35 V), then latches into low-impedance conduction until current falls below 150 mA. Its fail-safe mode ensures permanent short-circuit behavior under catastrophic surge, preventing open-circuit failure modes.

Thermal design is constrained by R_th(j-a) = 100 °C/W (with recommended footprint) and T_j operating range of –40 to +150 °C; it sustains non-repetitive surges up to 24 A for 0.2 s and delivers I²t = 20 A²s (16.6 ms), supporting coordination with upstream fuses or PTCs in telecom protection circuits.

Key Specifications

Pinout & Package

Package: DO-214AA (SMB), surface-mount, 2-terminal bidirectional device with cathode/anode symmetry. Dimensions: 3.30–3.95 mm length × 5.10–5.60 mm width × 1.90–2.45 mm height; thermal pad footprint per Figure 14 (1.62 × 5.84 mm).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thyristor surge suppressor applications.

Compared with SP1003-35 and TISP4240M3JR-S, SMP100LC-35 uniquely balances 55 pF capacitance, 100 A surge rating, and full GR-1089/ITU-T compliance - making it the preferred choice for certified high-speed telecom line protection where signal fidelity and standard adherence are non-negotiable.

Availability

SMP100LC-35 is available at Aetrix Electronics and suitable for DSL line card design, Ethernet PHY port hardening, industrial RS-485 interface protection, and central office DSLAM surge interface requiring stable component supply and long-term lifecycle support.

Supply support for SMP100LC-35 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, designing and manufacturing analog, power, microcontroller, and sensor solutions for automotive, industrial, and communications markets.

The SMP100LC series belongs to ST's Telecom Circuit Protector product line, engineered specifically to meet GR-1089 Core, ITU-T K20/K21, and IEC 61000-4-5 requirements for fail-safe, low-capacitance surge suppression in high-data-rate access network equipment.

FAQ

What is the fail-safe behavior of SMP100LC-35, and how does it differ from standard TVS diodes?

The SMP100LC-35 enters a permanent low-impedance short-circuit state after a destructive surge, ensuring downstream circuitry remains protected even if the device is damaged. Unlike unidirectional TVS diodes-which degrade to open-circuit or high-leakage states-this fail-safe mode prevents latent system failures and supports safety-critical telecom deployments compliant with UL60950 and IEC 950.

Can SMP100LC-35 be used on 10GBASE-T Ethernet interfaces?

No. With 55 pF capacitance at 2 V, SMP100LC-35 introduces excessive insertion loss above ~50 MHz, making it unsuitable for 10GBASE-T (operating up to 800 MHz). It is validated for ADSL2+, VDSL2, and 1000BASE-T (≤100 MHz), where its capacitance meets IEEE 802.3 and ITU-T G.993.2 signal integrity requirements.

How is coordination achieved between SMP100LC-35 and upstream fusing in telecom line cards?

Coordination relies on the device's I²t = 20 A²s (16.6 ms) and non-repetitive surge rating of 24 A (0.2 s). A properly selected fast-acting fuse (e.g., 0.5 A, I²t < 15 A²s) will clear before the TSS reaches thermal runaway, allowing the SMP100LC-35 to clamp and divert energy while preserving system uptime - a key requirement in GR-1089 Core-compliant designs.

Does SMP100LC-35 require a heatsink for continuous operation?

No heatsink is required under normal operation because the device only conducts during transient events (microsecond to millisecond duration). Its R_th(j-a) = 100 °C/W is sufficient for pulsed energy dissipation. However, PCB layout must follow ST's recommended SMB footprint (1.62 × 5.84 mm copper pad) to ensure adequate thermal conduction and mechanical reliability during reflow and surge stress.