SM4T18CAY

SM4T18CAY is a four-channel surface-mount TVS diode array for transient protection. It guards up to four lines (ESD and surge) by shunting transient energy to a common ground. The “18” usually points to a nominal 18 V working/standoff voltage, but exact figures (Vwm, Vclamp, leakage, capacitance, current rating) vary by vendor—check the datasheet. Features commonly include low input capacitance for high-speed lines and fast response. Typical applications: protecting interfaces such as USB, CAN/LIN, Ethernet, or other multi-line data/power lines, placed close to connectors. To use, mount near the connector with a solid ground reference and follow recommended PCB layout to minimize loop area.

Pin count: 2 pins — Anode and Cathode (two-terminal device, SMC/DO‑214 package).
Function: SM4T18CAY is a unidirectional TVS (transient-voltage‑suppressor) diode with an 18 V stand‑off class; it clamps and absorbs high‑energy transient overvoltages (ESD, lightning, surge/IEC 61000‑4‑5) to protect circuits and power rails. Typical rating: high peak pulse power (hundreds of watts) and fast response to transients.

Manufacturer: Littelfuse, Inc.
What kind of company: An American multinational that designs and manufactures circuit protection and power-control components, including fuses, TVS diodes, ESD protectors, varistors, and related devices for electronics, automotive, and industrial applications.

SM4T18CAY is a 4-channel TVS diode array with 18 V nominal standoff, used for ESD and transient protection on signal and power lines.
Typical applications:
- Automotive electronics (ECUs, sensors, CAN/LIN networks, infotainment)
- Industrial controls and I/O interfaces (RS-485, fieldbus, motor drives, power supplies)
- Consumer/telecom equipment with exposed connectors (USB, HDMI, telecom lines)
- Any 12–24 V system needing four-line protection with low capacitance to preserve high-speed signal integrity.

6-pin SOT-23 package (SC-70-6).