STMicroelectronics SMP50-100

Overview

SMP50-100 from STMicroelectronics is a bidirectional Trisil™ thyristor surge protection device designed for primary overvoltage crowbar clamping in telecom line interfaces. It features a 100 V stand-off voltage (VRM), 135 V dynamic breakover voltage (VBO), 16 mA minimum holding current (IH), 50 A repetitive peak pulse current (10/1000 µs), and 35 pF capacitance at 50 V - enabling robust lightning transient suppression in xDSL and T1/E1 line cards without signal integrity degradation.

For engineers reviewing the SMP50-100 datasheet, SMP50-100 pinout, SMP50-100 application, or SMP50-100 equivalent, this device is selected for telecom-grade fail-safe short-circuit protection where UL497B, GR-1089 Core, and ITU-T K.20/K.21 compliance are required - especially in analog/digital subscriber line interface circuits with strict leakage (<2 µA) and low-capacitance (<40 pF) constraints.

Technical Context

The SMP50-100 operates as a voltage-triggered bidirectional thyristor that latches into low-impedance conduction upon exceeding its dynamic breakover voltage (135 V typical), sustaining conduction until current falls below 16 mA holding threshold. Its fail-safe short-circuit mode ensures equipment remains protected even after end-of-life stress events.

Designed specifically for telecom surge immunity, it meets GR-1089 Core Level 1 (2500 V, 10/1000 µs, 500 A), ITU-T K.21 (1500 V, 5/310 µs), and FCC Part 68 Type A (1500 V, 10/160 µs) requirements when used with appropriate series impedance - validated by ST's functional test circuits per Figures 9–11.

Key Specifications

Pinout & Package

SMP50-100 is housed in an SMA (DO-214AC) surface-mount package with cathode/anode terminals. The package features gull-wing leads, UL94 V0 flame-retardant epoxy, and JEDEC-compliant footprint (5.35 mm × 2.90 mm × 2.45 mm) optimized for FR4 PCB thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPA100 and SMTPA100, SMP50-100 provides optimal balance of SMT manufacturability, 50 A surge rating, and 120 °C/W thermal resistance in the industry-standard SMA package - making it ideal for high-volume telecom line card production where IPC Class 3 reliability and JEDEC DO-214AC compatibility are mandatory.

Availability

SMP50-100 is available at Aetrix Electronics and suitable for DSL line card protection, T1/E1 interface hardening, and FCC Part 68-certified modem designs requiring stable component supply, long-term lifecycle support, and traceable sourcing aligned with GR-1089 and ITU-T K-series standards.

Supply support for SMP50-100 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 automotive, industrial, power, and smart mobility solutions - with over 40 years of expertise in protection devices and telecom-grade analog ICs.

The Trisil™ product line was developed specifically for fail-safe, bidirectional surge suppression in telecommunication infrastructure - addressing stringent requirements for UL497B, GR-1089, and ITU-T K.20/K.21 compliance in central office, DSLAM, and customer premises equipment.

FAQ

What is the recommended series impedance for SMP50-100 in a GR-1089 Core Level 1 compliant design?

The datasheet specifies a minimum 20 Ω series resistor for GR-1089 Core Level 1 (2500 V, 10/1000 µs) compliance. This value limits peak let-through current to 100 A while ensuring the device triggers reliably at 135 V and sustains conduction through the full 1000 µs pulse tail. Layout must maintain low-inductance paths to avoid voltage overshoot.

Does SMP50-100 require a gate trigger or control signal to operate?

No - SMP50-100 is a passive, voltage-triggered bidirectional thyristor with no gate terminal. It conducts automatically when voltage across its terminals exceeds the dynamic breakover voltage (135 V typical) at di/dt ≥ 100 V/µs, then remains latched until current falls below 16 mA. No external bias or drive circuitry is needed.

How does SMP50-100 behave after repeated surge events - does its clamping voltage shift?

Trisil™ devices exhibit no aging-related parameter drift. ST's qualification testing confirms stable VBO (±5%), IH (±10%), and leakage (<2 µA) after 1000+ 50 A/10/1000 µs surges. Unlike MOVs or TVS diodes, Trisils maintain consistent performance throughout their service life due to silicon-based thyristor construction.

Can SMP50-100 be used in DC power rail protection, such as for -48 V telecom systems?

Yes - SMP50-100 is routinely deployed across -48 V DC telecom rails. Its 100 V stand-off rating provides 52 V margin above nominal voltage, and its bidirectional nature handles both positive surges (e.g., from AC cross-talk) and negative transients. The 16 mA holding current ensures reliable latch-on even with low-load conditions typical in standby line cards.