STMicroelectronics SMTPA62

Overview

SMTPA62 from STMicroelectronics is a bidirectional Trisil™ surge protection device in SMB (DO-214AA) package, designed for telecom line card protection with 62 V stand-off voltage, 85 V dynamic breakover voltage, 50 A repetitive peak pulse current (10/1000 µs), and 20 pF capacitance at 50 V. It provides fail-safe short-circuit crowbar action in lightning and AC-induced transients on analog/digital xDSL/T1/E1 lines.

For engineers reviewing the SMTPA62 datasheet, SMTPA62 pinout, SMTPA62 application, or SMTPA62 equivalent, this device is selected for telecom-grade transient immunity where low capacitance, stable holding current (>150 mA), UL497B/GR-1089 compliance, and JEDEC-registered SMB packaging are critical to meet FCC Part 68 and IEC61000-4-5 requirements.

Technical Context

The SMTPA62 operates as a voltage-triggered bidirectional crowbar, entering low-impedance conduction when transient voltage exceeds its dynamic breakover threshold (85 V typical). Its fail-safe short-circuit mode ensures equipment remains protected even after device degradation.

It sustains repetitive 50 A surges per 10/1000 µs waveform and maintains ≤2 µA leakage at 56 V reverse bias. Thermal resistance junction-to-leads is 20 °C/W, enabling robust power dissipation during clamping in telecom line interface circuits.

Key Specifications

Pinout & Package

SMB (DO-214AA) package: cathode-anode symmetrical bidirectional structure; no polarity marking required; leads rated for 260 °C soldering (10 s).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMTPA62, TPA62 offers superior thermal dissipation in through-hole mounting but lacks SMT automation support, while SMP50-62 reduces board area by ~30% but increases thermal impedance-requiring careful layout for repeated surge duty cycles.

Availability

SMTPA62 is available at Aetrix Electronics and suitable for analog line cards (xDSL/T1/E1), digital terminal interfaces (modem/fax), and central office equipment requiring stable component supply, full traceability, and lifecycle continuity.

Supply support for SMTPA62 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, designing and manufacturing silicon solutions for automotive, industrial, and communications markets with emphasis on reliability and safety certification.

The Trisil™ product line was developed specifically for fail-safe, bidirectional surge protection in telecom infrastructure-targeting GR-1089, ITU-T K-series, and FCC Part 68 compliance without external bias or control circuitry.

FAQ

What is the fail-safe behavior of SMTPA62 during end-of-life degradation?

SMTPA62 enters a permanent short-circuit state upon wear-out, maintaining clamping functionality rather than failing open. This behavior is certified per UL497B and ensures continued overvoltage protection in safety-critical telecom applications, eliminating risk of unclamped transients damaging downstream circuitry.

Can SMTPA62 be used in DC-powered analog phone line interfaces?

Yes-its 62 V stand-off voltage and ≤2 µA leakage at 56 V allow direct placement across POTS line pairs without affecting -48 V DC bias or ringing detection. The 150 mA minimum holding current ensures stable conduction during 20 ms ring surges defined in FCC Part 68.

How does SMTPA62 coordinate with a downstream gas discharge tube (GDT)?

SMTPA62's 85 V dynamic VBO provides precise clamping upstream of a 90 V GDT, limiting let-through voltage during fast transients while allowing the GDT to handle high-energy follow current. This staged protection meets GR-1089 Core Level 1 and ITU-T K20 requirements with optimized energy sharing.

Is SMTPA62 compliant with RoHS and REACH regulations?

Yes-SMTPA62 is supplied in ECOPACK®-compliant SMB packages with lead-free second-level interconnects, fully conforming to RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006, with material declarations available via ST's official product portal.