STMicroelectronics SM15T10CA

Overview

SM15T10CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode in SMC package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4). It features 10 V standoff voltage (VRM), 14.5 V clamping voltage at 538 A (8/20 µs), and 1500 W peak pulse power (10/1000 µs), enabling robust protection of USB, Ethernet, and industrial I/O interfaces.

For engineers reviewing the SM15T10CA datasheet, SM15T10CA pinout, SM15T10CA application, or SM15T10CA equivalent, key selection criteria include bidirectional clamping behavior, low leakage (<0.2 µA at 25 °C), high junction temperature capability (150 °C), and compatibility with automated SMT assembly per J-STD-020 MSL level 1.

Technical Context

This TVS diode employs planar silicon technology to achieve stable breakdown characteristics across temperature (αT = 7.3 × 10⁻⁴ /°C) and low dynamic resistance (RD = 0.015 Ω at 25 °C). Its bidirectional structure enables symmetric clamping for AC-coupled lines without polarity constraints.

The device operates over -55 °C to +150 °C junction temperature range and maintains ≤1 µA reverse leakage up to VRM = 10 V. Clamping voltage scales predictably with surge current via VCL(max) = VCL − RD × (IPP − IPP_appli), supporting precise system-level surge margining.

Key Specifications

Pinout & Package

SM15T10CA is housed in an SMC (DO-214AB) surface-mount package with two terminals: Cathode (K) and Anode (A). The bidirectional configuration means both terminals behave identically under reverse polarity transients, eliminating orientation dependency during placement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional TVS diode applications.

Compared with SMBJ10CA and 1.5KE10CA, SM15T10CA delivers superior clamping precision (14.5 V vs ≥17 V), lower leakage (1 µA vs ≥5 µA), and full MSL-1 reflow compatibility - making it optimal for modern high-reliability SMT systems demanding repeatable surge performance.

Availability

SM15T10CA is available at Aetrix Electronics and suitable for industrial I/O protection, USB 2.0 interface hardening, and Ethernet PHY surge suppression requiring stable component supply, traceable sourcing, and long-term lifecycle support.

Supply support for SM15T10CA 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 microcontroller technologies for industrial, automotive, and consumer markets.

SM15T10CA belongs to ST's high-power planar TVS diode product line, engineered specifically for robust electrostatic and surge protection in space-constrained, thermally demanding applications such as factory automation and automotive body electronics.

FAQ

What is the difference between SM15T10A and SM15T10CA?

SM15T10A is unidirectional and protects only one polarity of transient (e.g., positive surges relative to ground), while SM15T10CA is bidirectional and clamps both positive and negative transients symmetrically. This makes SM15T10CA ideal for AC-coupled or differential signal lines like RS-485 or USB, where polarity is undefined or alternates.

Can SM15T10CA be used in place of a unidirectional TVS in DC-biased circuits?

Yes, but with caution: its bidirectional structure allows conduction in both directions once V_BR is exceeded, so it must not be placed across a DC supply rail unless the circuit inherently references both sides to ground. In DC-biased signal lines (e.g., 3.3 V UART), it functions correctly if the bias voltage remains well below VRM (10 V).

What is the thermal resistance (R_th(j-a)) of SM15T10CA on a standard FR4 PCB?

On a recommended footprint with 70 µm copper thickness, R_th(j-a) is approximately 100 °C/W for a single pulse. With 2 cm² copper area per lead, it improves to ~40 °C/W - critical for sustaining repeated surges at elevated ambient temperatures without exceeding 150 °C Tj.

Does SM15T10CA meet UL 497B for telecom surge protection?

No - UL 497B applies to primary protector assemblies for telephone network interfaces, which require different test waveforms and coordination with secondary protectors. SM15T10CA complies with UL 497B file QVGQ2.E136224 only as a *component* used within a certified system, not as a standalone telecom protector.