STMicroelectronics SM6T27CA

Overview

SM6T27CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for robust ESD and surge protection on signal/power lines in industrial, automotive, and telecom interfaces. It delivers 600 W peak pulse power (10/1000 µs), clamps at 37.5 V (max) under 16 A IPP, and operates up to 150 °C junction temperature - enabling reliable protection in high-temperature SMPS and I/O circuitry.

For engineers reviewing the SM6T27CA datasheet, SM6T27CA pinout, SM6T27CA application, or SM6T27CA equivalent, key selection criteria include bidirectional clamping voltage (V_CL = 37.5 V @ 16 A), low dynamic resistance (R_D = 0.569 Ω), IEC 61000-4-2 ±30 kV contact/air discharge compliance, and SMB package thermal performance under sustained transients.

Technical Context

The SM6T27CA employs planar silicon avalanche technology to achieve fast response (<1 ns) and stable clamping across temperature. Its bidirectional structure symmetrically suppresses positive and negative transients without polarity dependency, making it suitable for AC-coupled or differential bus lines like RS-485, CAN FD, and Ethernet PHY interfaces.

It meets UL497B recognition (file E136224) as an isolated loop circuit protector and exceeds IEC 61000-4-4 level 4 (4 kV) and IEC 61000-4-2 level 4 (±30 kV), with leakage current limited to 0.2 μA at 25 °C and 1 μA at 85 °C - critical for low-power sensor nodes and battery-backed systems.

Key Specifications

Pinout & Package

The SM6T27CA is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode (K) and Anode (A). The bidirectional configuration means both terminals function identically - no polarity orientation required during placement. Matte tin-plated leads ensure solderability per J-STD-002 and JESD 22-B102 E3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ27CA and P6SMB27CA, the SM6T27CA offers superior high-temperature reliability (150 °C T_j max), lower leakage, and UL497B certification - making it the preferred choice for industrial control, medical, and telecom applications demanding long-term stability and regulatory compliance.

Availability

SM6T27CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, telecom DSL line interfaces, and medical ECG input protection requiring stable component supply across multi-year production cycles.

Supply support for SM6T27CA 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, designing and manufacturing microcontrollers, power devices, sensors, and protection components for industrial, automotive, and consumer markets.

The SM6T series belongs to ST's high-reliability TVS portfolio, engineered specifically for robust transient suppression in harsh environments - emphasizing low leakage, high-temperature operation, and regulatory compliance for mission-critical signal integrity.

FAQ

What is the standoff voltage (V_RM) of SM6T27CA?

The maximum reverse standoff voltage (V_RM) is 24 V - meaning the device remains non-conductive up to this DC or continuous AC voltage, ensuring no loading or leakage impact on 24 V signal lines during normal operation. This value is derived from the 27 V nominal breakdown voltage with 10% tolerance, confirmed in Table 2 of DS0684 Rev 15.

Does SM6T27CA require orientation during PCB placement?

No - SM6T27CA is a bidirectional TVS diode, so its two terminals are functionally identical. There is no cathode/anode polarity; either terminal may connect to either side of the protected line. The device marking "MP" (per Table 6) appears on one end but does not indicate polarity, consistent with bidirectional SMB packages.

How does SM6T27CA perform under repeated surge stress?

SM6T27CA maintains stable clamping characteristics over repeated 10/1000 µs surges up to 600 W when mounted on the recommended IPC7531-compliant SMB footprint with ≥2 cm² copper area per lead. Thermal impedance data (Figure 11) shows Z_th(j-a) ≤ 45 °C/W for single pulses, enabling full power dissipation without junction overheating.

Is SM6T27CA compliant with RoHS and REACH?

Yes - SM6T27CA is manufactured in ST's ECOPACK2-compliant facilities and meets RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. Lead finish is matte tin (Pb-free), and halogen content is below 900 ppm total, as verified in ST's material declarations and ECOPACK documentation.