STMicroelectronics SM15T36CA

Overview

SM15T36CA 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 a 36 V standoff voltage (VRM), 49.9 V clamping voltage at 30 A (8/20 µs), 1500 W peak pulse power (10/1000 µs), and operates up to 150 °C junction temperature. Used in telecom line interfaces and industrial I/O protection.

For engineers reviewing the SM15T36CA datasheet, SM15T36CA pinout, SM15T36CA application, or SM15T36CA equivalent, this page delivers verified electrical parameters, thermal derating behavior, bidirectional clamping performance, low leakage (<0.2 µA at 25 °C), and SMC footprint compliance per IPC7531 and JEDEC MO-213AB.

Technical Context

The SM15T36CA employs planar silicon avalanche technology to deliver symmetrical clamping in both polarities, enabling robust protection of balanced signal lines such as RS-485, CAN FD, and Ethernet PHY interfaces. Its dynamic resistance (RD = 0.17 Ω at 25 °C) ensures minimal voltage overshoot during fast transients.

Thermal design is supported by validated junction-to-ambient thermal resistance (R_th(j-a) ≈ 100 °C/W on standard FR4 with 3.14 cm² copper per lead) and derated peak power capability - down to 1250 W at T_j = 150 °C for 10/1000 µs pulses - ensuring reliability under sustained surge stress.

Key Specifications

Pinout & Package

SM15T36CA is housed in an SMC (DO-214AB) surface-mount package per JEDEC MO-213AB, with matte tin-plated leads compliant with J-STD-002 and JESD 22-B102 E3. The package measures 7.75–8.15 mm × 5.55–6.25 mm × 2.45 mm max height and uses a standardized IPC7531 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ36CA and P6SMB36CA, SM15T36CA provides 2.5× higher surge power handling, 8.2 V lower clamping at rated current, and certified 30 kV ESD immunity - making it the preferred choice for mission-critical industrial and automotive communication ports requiring robust, standards-compliant protection.

Availability

SM15T36CA is available at Aetrix Electronics and suitable for industrial RS-485 networks, automotive CAN FD bus nodes, and telecom DSL line cards requiring stable component supply across multi-year production cycles.

Supply support for SM15T36CA 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, delivering intelligent power, sensing, and control solutions for industrial, automotive, and consumer markets.

The SM15T series belongs to ST's high-power TVS portfolio, engineered specifically for system-level IEC 61000-4-2/4-4 compliance in space-constrained, high-temperature environments - targeting telecom infrastructure, factory automation, and vehicle networking.

FAQ

What is the maximum clamping voltage of SM15T36CA under a 30 A 8/20 µs surge?

The maximum clamping voltage (V_CL) is 49.9 V at 30 A for an 8/20 µs waveform, measured at T_j = 25 °C. This value increases with junction temperature at a coefficient α_T = 9.9 × 10⁻⁴/°C, reaching ~52.4 V at T_j = 125 °C per the datasheet's V_CL vs. T_j formula.

Is SM15T36CA suitable for protecting high-speed data lines like USB 2.0 or HDMI?

No - its typical junction capacitance is 120 pF at 0 V, which exceeds the <5 pF requirement for USB 2.0 and HDMI signal integrity. It is intended for lower-speed, high-energy interfaces such as RS-485, CAN, and telecom line cards where capacitance is less critical than surge energy handling.

How does SM15T36CA differ from unidirectional SM15T36A?

SM15T36CA is bidirectional with symmetrical V_BR and V_CL for both polarities, enabling protection of AC-coupled or differential lines without polarity concerns. SM15T36A is unidirectional, conducting only in reverse bias - requiring careful orientation and unsuitable for balanced signals unless paired with another device.

What PCB layout practices maximize thermal performance for SM15T36CA?

Use ≥3.14 cm² of 70 µm-thick copper per pad (per Figure 12), connect both pads to internal ground planes via multiple thermal vias, and avoid narrow traces between the TVS and protected IC. This reduces R_th(j-a) from ~100 °C/W to ~60 °C/W, improving surge survivability during repeated 10/1000 µs events.