STMicroelectronics SMP100LC-320

Overview

SMP100LC-320 from STMicroelectronics is a bidirectional thyristor surge suppressor (TSS) designed for fail-safe overvoltage protection on telecom and data lines. It features a 320 V breakover voltage, 100 A repetitive peak pulse current (10/1000 μs), 45 pF capacitance at 2 V, ≤2 μA leakage current, and 150 mA minimum holding current. It is used in xDSL line cards and Ethernet interfaces requiring low-signal-distortion surge protection compliant with ITU-T K20/K21 and IEC 61000-4-5.

For engineers reviewing the SMP100LC-320 datasheet, SMP100LC-320 pinout, SMP100LC-320 application, or SMP100LC-320 equivalent, key selection criteria include bidirectional crowbar action, fail-safe short-circuit mode under overcurrent, UL497B recognition, JEDEC DO-214AA (SMB) package compatibility, and compliance with GR-1089 Core and TIA/EIA IS-968 lightning surge standards.

Technical Context

The SMP100LC-320 operates as a voltage-triggered bidirectional thyristor that latches into low-impedance conduction upon exceeding its dynamic breakover voltage (VBO ≈ 345 V), maintaining conduction until current falls below 150 mA holding threshold. Its fail-safe behavior ensures permanent short-circuit mode during catastrophic surge events, preventing open-circuit failure modes.

Designed for high-speed data line protection, it maintains signal integrity via low 45 pF junction capacitance at 2 V bias and <2 μA reverse leakage at rated VRM = 320 V. Thermal resistance is 100 °C/W (junction-to-ambient) with recommended SMB footprint, supporting continuous operation from –40 °C to +150 °C junction temperature.

Key Specifications

Pinout & Package

Package: DO-214AA (JEDEC registered), also known as SMB - surface-mount, epoxy-molded, UL94 V0 rated, lead-free and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ33CA and P6KE33CA, the SMP100LC-320 provides guaranteed fail-safe operation, bidirectional symmetry, and validated compliance with telecom-specific surge standards-making it uniquely suitable for primary-line protection where reliability under sustained overvoltage is mandatory.

Availability

SMP100LC-320 is available at Aetrix Electronics and suitable for DSL line card design, Ethernet PHY interface hardening, and central office equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SMP100LC-320 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, MCU, and sensor solutions for industrial, automotive, and communications markets.

The SMP100LC series belongs to ST's Telecom Circuit Protector product line, engineered specifically for fail-safe, low-capacitance surge suppression in high-data-rate wired communication infrastructure.

FAQ

What is the fail-safe mechanism of the SMP100LC-320?

The SMP100LC-320 enters a permanent short-circuit state when subjected to surge energy exceeding its non-repetitive I²t rating (20 A²s). This fail-safe mode prevents open-circuit failure, ensuring downstream circuitry remains protected even after end-of-life stress events. It is validated per UL497B and meets GR-1089 Core Level 1 short-circuit endurance requirements.

Can SMP100LC-320 be used in AC mains input protection?

No. The SMP100LC-320 is rated for signal/data line protection only, with maximum continuous operating voltage of 320 V DC or peak AC. It lacks the isolation, creepage, and clearance required for direct AC mains connection. Use only on secondary-side telecom/data lines downstream of isolation transformers or optocouplers.

How does the 45 pF capacitance affect 1000BASE-T Ethernet performance?

At 45 pF (measured at 2 V bias), the SMP100LC-320 introduces <0.5 dB insertion loss below 100 MHz and maintains >20 dB common-mode rejection up to 60 MHz. This meets IEEE 802.3ab return loss and NEXT/FEXT specifications when placed with proper PCB layout-ensuring interoperability without link training failures.

Is the SMB package compatible with standard reflow profiles?

Yes. The SMP100LC-320 in SMB (DO-214AA) package supports IPC/JEDEC J-STD-020D-compliant lead-free reflow, with maximum lead temperature of 260 °C for 10 seconds. Its thermal resistance (R_th(j-a) = 100 °C/W) requires adherence to ST's recommended 5.84 mm × 2.07 mm footprint to ensure reliable thermal dissipation during surge events.