STMicroelectronics SM6T220A

Overview

SM6T220A from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode in SMB package, designed for high-energy surge protection of sensitive electronics. It delivers 600 W peak pulse power (10/1000 µs), clamps at 328 V (max) under 2 A IPP, and operates up to 150 °C junction temperature-ideal for industrial power supply input stages and telecom line interfaces exposed to IEC 61000-4-4 level 4 (4 kV) transients.

For engineers reviewing the SM6T220A datasheet, SM6T220A pinout, SM6T220A application, or SM6T220A equivalent, key selection criteria include its 220 V standoff voltage (VRM = 188 V), low leakage (<0.2 µA @ 25 °C), dynamic resistance of 15.2 Ω, and UL497B recognition (E136224) for isolated loop circuit protection.

Technical Context

The SM6T220A employs planar silicon junction technology optimized for low leakage and stable clamping across temperature. Its unidirectional configuration provides asymmetric breakdown behavior-reverse-biased conduction only-enabling precise overvoltage clamping on DC rails without forward conduction interference.

It meets IEC 61000-4-2 (30 kV air/contact discharge) and IEC 61000-4-4 (4 kV, 8/20 µs) immunity requirements, with clamping voltage defined by VCL = VBR + RD × IPP. At Tj = 150 °C, peak pulse power capability remains at 350 W (10/1000 µs), supporting high-reliability operation in thermally constrained environments.

Key Specifications

Pinout & Package

SM6T220A is housed in an SMB (DO-214AA) surface-mount package with two terminals: cathode and anode. The package measures 3.30–3.95 mm (D) × 5.10–5.60 mm (E) × 1.90–2.45 mm (A1) and features matte tin-plated leads compliant with J-STD-002 and MIL-STD-750 method 2026.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with SMBJ220A and P6SMB220A, SM6T220A uniquely provides UL497B certification (E136224) for isolated loop protection-critical for telecom and industrial safety standards-while maintaining identical clamping performance and thermal robustness up to 150 °C.

Availability

SM6T220A is available at Aetrix Electronics and suitable for industrial AC/DC power input, telecom line interface protection, motor drive DC bus protection, and renewable energy inverter input requiring stable component supply across extended temperature and surge stress conditions.

Supply support for SM6T220A 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, and power discrete solutions with vertical manufacturing and broad IP portfolio.

The SM6T series belongs to ST's high-reliability TVS diode product line, engineered specifically for robust surge immunity in harsh industrial and telecom infrastructure environments where long-term stability and regulatory compliance are mandatory.

FAQ

What is the maximum clamping voltage of SM6T220A under a 10/1000 µs surge?

The maximum clamping voltage (VCL) of SM6T220A is 328 V when subjected to a 2 A peak pulse current with 10/1000 µs waveform. This value is measured at Tamb = 25 °C and represents the upper bound voltage imposed on the protected circuit during standardized surge testing per IEC 61000-4-5.

Does SM6T220A support bidirectional surge protection?

No, SM6T220A is a unidirectional TVS diode, conducting only in reverse breakdown mode. For bidirectional protection, the equivalent part is SM6T220CA, which provides symmetrical clamping for AC-coupled or floating signal lines. Pinout and package are identical, but polarity marking and IV curve differ.

How does SM6T220A perform at elevated junction temperatures?

At Tj = 150 °C, SM6T220A maintains 350 W peak pulse power (10/1000 µs), approximately 58% of its 25 °C rating. Its VBR and VCL increase linearly with temperature (αT = 10.8 × 10⁻⁴/°C), enabling predictable derating in thermally constrained designs such as enclosed power supplies or motor drives.

Is SM6T220A compatible with lead-free reflow soldering processes?

Yes, SM6T220A uses matte tin-plated leads qualified to J-STD-020 MSL level 1 and supports peak reflow temperatures up to 245 °C for 20–40 seconds. ST's recommended profile includes ramp rates ≤3 °C/s, soak at 150–200 °C for 60–120 s, and time above liquidus of 60–90 s-fully aligned with IPC/JEDEC standards.