STMicroelectronics SM6T6V8CA

Overview

SM6T6V8CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for IEC 61000-4-2 ESD and IEC 61000-4-4 surge protection on signal/power lines. It features a 6.8 V nominal breakdown voltage (V_BR = 6.45 V min / 7.14 V max), 10.5 V clamping voltage (V_CL) at 275 A (8/20 µs), and 600 W peak pulse power (10/1000 µs) in SMB package. Used to safeguard USB, RS-485, CAN, and sensor interfaces against fast transients.

For engineers reviewing the SM6T6V8CA datasheet, SM6T6V8CA pinout, SM6T6V8CA application, or SM6T6V8CA equivalent, key selection criteria include bidirectional clamping symmetry, low dynamic resistance (0.027 Ω), sub-1 µA leakage at 85 °C, and UL497B recognition for isolated loop circuits - all critical for industrial communication and automotive body electronics.

Technical Context

The SM6T6V8CA employs planar silicon junction technology optimized for low leakage (<1 µA @ 85 °C) and stable clamping over temperature (α_T = 5.7 × 10⁻⁴/°C). Its bidirectional structure provides symmetrical protection for AC-coupled or floating signal paths without polarity dependency.

Clamping performance is defined by V_CL = V_BR(max) + R_D × I_PP, with R_D = 0.027 Ω (8/20 µs) enabling tight voltage control during 275 A surges. It meets IEC 61000-4-2 level 4 (±30 kV air/contact discharge) and IEC 61000-4-4 level 4 (4 kV), validated per UL497B as an isolated loop circuit protector (E136224).

Key Specifications

Pinout & Package

The SM6T6V8CA is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode (K) and Anode (A). The bidirectional configuration means both terminals are functionally symmetric - no polarity marking required for AC protection applications. Matte tin-plated leads comply 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 bidirectional TVS diode applications.

Compared with SMAJ6.8CA and 1.5KE6.8CA, the SM6T6V8CA delivers superior clamping precision (10.5 V vs. ≥11.5 V), verified UL497B listing for isolated circuits, and optimized thermal performance up to 150 °C - making it the preferred choice for compact, safety-compliant industrial and automotive signal protection.

Availability

SM6T6V8CA is available at Aetrix Electronics and suitable for industrial RS-485 networks, automotive body control modules, and smart sensor signal conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SM6T6V8CA 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.

The SM6T series belongs to ST's transient protection portfolio, engineered specifically for high-reliability ESD and surge suppression in space-constrained, thermally demanding applications - emphasizing low leakage, bidirectional symmetry, and safety agency recognition.

FAQ

Is SM6T6V8CA unidirectional or bidirectional?

The SM6T6V8CA is a bidirectional TVS diode, indicated by the "CA" suffix in its part number. Its symmetrical V_BR and V_CL characteristics enable identical clamping for both positive and negative transients, making it ideal for AC-coupled or floating signal lines such as RS-485, CAN, and LIN buses without polarity concerns.

What is the maximum clamping voltage at 275 A (8/20 µs)?

The maximum clamping voltage (V_CL) for SM6T6V8CA is 10.5 V at 275 A under 8/20 µs surge conditions, as specified in Table 2 of DS0684 Rev 15. This value is measured at T_amb = 25 °C and accounts for dynamic resistance (R_D = 0.027 Ω), ensuring predictable voltage limiting during fast-rising transients.

Does SM6T6V8CA meet UL497B requirements?

Yes - SM6T6V8CA is recognized to UL497B as an isolated loop circuit protector under agency file number E136224. This certification confirms its suitability for protecting secondary-side circuits in telecom, industrial control, and medical devices where galvanic isolation and surge withstand are mandated by safety standards.

Can SM6T6V8CA replace SM6T6V8A in a design?

No - SM6T6V8A is unidirectional and intended for DC-biased lines (e.g., power supply rails), while SM6T6V8CA is bidirectional for AC or floating signals. Substituting them risks incomplete protection: the unidirectional version will not clamp negative transients, and the bidirectional version may conduct during normal reverse bias in DC applications.