STMicroelectronics TPA220

Overview

TPA220 from STMicroelectronics is a bidirectional Trisil™ thyristor surge protection device in DO-15 package, designed for telecom line protection with 220 V standoff voltage, 285 V dynamic breakover voltage, 12 mA minimum holding current, and 50 A repetitive peak pulse current (10/1000 µs). It safeguards analog/digital line cards (xDSL, T1/E1) against lightning surges per GR-1089, ITU-T K20/K21, and FCC Part 68.

For engineers reviewing the TPA220 datasheet, TPA220 pinout, TPA220 application, or TPA220 equivalent, key selection criteria include its fail-safe short-circuit behavior under overvoltage, low 25 pF capacitance at 2 V bias, 2 µA max leakage at 198 V, UL497B and UL94 V0 certification, and compatibility with telecom surge standards requiring ≥50 A pulse handling and ≤20 Ω series resistance.

Technical Context

The TPA220 operates as a crowbar-type transient voltage suppressor that latches into low-impedance conduction upon exceeding its dynamic breakover voltage (285 V), maintaining conduction until current falls below 12 mA holding threshold. Its bidirectional symmetry enables AC line protection without polarity constraints.

Thermal design relies on DO-15 package's 100 °C/W junction-to-ambient thermal resistance (with recommended footprint) and 60 °C/W junction-to-leads resistance, supporting sustained surge dissipation when paired with appropriate PCB copper area and series impedance.

Key Specifications

Pinout & Package

TPA220 uses a DO-15 axial-leaded package (6.05–6.75 mm length, 2.95–3.53 mm diameter) with two identical terminals; no polarity marking required due to bidirectional symmetry.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMTPA220 and TPA200, TPA220 uniquely balances 220 V standoff margin, DO-15 mechanical robustness, and fail-safe reliability-making it optimal for field-serviceable telecom hardware where manual replacement and long-term stability are critical.

Availability

TPA220 is available at Aetrix Electronics and suitable for DSL line card protection, T1/E1 interface hardening, and central office terminal surge suppression requiring stable component supply across extended product lifecycles.

Supply support for TPA220 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 ICs with broad industrial and communications portfolio coverage.

TPA220 belongs to ST's Trisil™ family of bidirectional thyristor surge protectors, engineered specifically for fail-safe, high-energy lightning protection in telecom infrastructure meeting GR-1089, ITU-T K20/K21, and FCC Part 68 standards.

FAQ

What is the fail-safe behavior of TPA220 during end-of-life degradation?

TPA220 fails short-circuit, maintaining low-impedance conduction after triggering-unlike MOVs or TVS diodes that degrade open-circuit. This ensures continued protection even after repeated surge exposure, preventing unclamped transients from reaching downstream circuitry.

How does TPA220 coordinate with a gas discharge tube (GDT) in a two-stage telecom protection circuit?

In staged protection, the GDT handles high-energy surges first (e.g., 5 kA), then fires the TPA220 at ~285 V to clamp residual voltage. The TPA220's fast response (<100 ns) and low clamping voltage limit stress on downstream ICs, while its 12 mA holding current ensures sustained conduction until GDT extinguishes.

Can TPA220 be used in AC mains input protection?

No-TPA220 is rated for telecom signal-line protection only (max 220 V standoff). Its 285 V breakover voltage and 12 mA holding current are unsuitable for 120/230 VAC mains, where higher standoff, thermal derating, and regulatory certifications (e.g., UL1449) are mandatory.

What is the maximum recommended series resistor value when using TPA220 on a 48 V telecom line?

Per GR-1089 Core Level 1, the maximum series resistor is 20 Ω to limit follow current during clamping. For 48 V nominal lines, this yields ~2.4 A follow current-well above TPA220's 12 mA holding threshold, ensuring reliable crowbar action without premature dropout.