Specifications
| Attribute | Value |
| Supplier | STMicroelectronics |
| Package / Case | Tape & Reel (TR),Cut Tape (CT) |
| Series | Automotive, AEC-Q101, SM4TY, TRANSIL™ |
| Part Status | Active |
| Type | Zener |
| Unidirectional Channels | 1 |
| Voltage - Reverse Standoff (Typ) | 15V |
| Voltage - Breakdown (Min) | 16.7V |
| Voltage - Clamping (Max) @ Ipp | 32.5V |
| Current - Peak Pulse(10 / 1000µs) | 71A (8/20µs) |
| Power - Peak Pulse | 400W |
| Power Line Protection | No |
| Applications | Automotive |
| Operating Temperature | -55°C ~ 150°C (TJ) |
| Mounting Type | Surface Mount |
Overview
Description
SM4T18AY is a part in the SM4T family of surface-mount transient-voltage-suppressor (TVS) diodes. These devices are used to protect sensitive electronics from voltage surges and electrostatic discharges on power rails and data lines, common in automotive, industrial, and telecom equipment. The “18” in the part name typically signals a nominal standoff voltage around 18 V, but exact electrical characteristics—such as breakdown voltage, clamping voltage, and whether the part is unidirectional or bidirectional—vary by variant. SM4T diodes are designed for fast response, low leakage, and high peak pulse current capability, and they come in standard SMT packages suited for automated assembly. For precise specs (V_RWM, V_BR, V_CL, I_PP, packaging), refer to the manufacturer’s datasheet for SM4T18AY. If you’d like, I can help locate and summarize the exact datasheet details.
Equivalent
SM4T18AY is a 4‑line TVS diode array with about 18 V working voltage (typically in SOT‑23‑6). There isn’t a single universal cross‑ref; exact equivalents depend on package/polarity and ratings. Closest 4‑channel 18 V TVS arrays from major vendors include Littelfuse, ON Semiconductor, Bourns, and Nexperia. To provide precise cross references, please share package (SOT‑23‑6), direction (unidirectional/bidirectional), Vwm/Vbr, IPP, and footprint. I’ll supply exact part numbers.
Pinout
SM4T18AY is a 4-channel transient-voltage-suppressor (TVS) diode array for ESD/surge protection. It comes in a 6-pin package (SOT‑23/SC‑74A) with four signal lines plus a common ground (two ground pins in the package). Each line is clamped to ground during transients to protect connected circuitry.
Manufacturer
Manufacturer: Littelfuse, Inc.
What kind of company: A global electronics components company specializing in circuit protection devices (fuses, TVS diodes, ESD protection, and related protection components).
What kind of company: A global electronics components company specializing in circuit protection devices (fuses, TVS diodes, ESD protection, and related protection components).
Application
SM4T18AY is a 4-line TVS diode array (stand-off voltage ~18V) for multi-line protection. Applications:
- ESD and surge protection for four I/O lines
- High-speed interfaces and serial buses: USB, HDMI/DisplayPort, Ethernet
- Automotive electronics and gateways (12V systems)
- Industrial/IoT equipment, edge connectors, and protection on power rails and signal lines
- CAN/LIN, RS-485, RS-232, I2C/SPI interfaces
In short, use it to guard multiple I/O lines and connectors against transient events in consumer, automotive, and industrial electronics.
- ESD and surge protection for four I/O lines
- High-speed interfaces and serial buses: USB, HDMI/DisplayPort, Ethernet
- Automotive electronics and gateways (12V systems)
- Industrial/IoT equipment, edge connectors, and protection on power rails and signal lines
- CAN/LIN, RS-485, RS-232, I2C/SPI interfaces
In short, use it to guard multiple I/O lines and connectors against transient events in consumer, automotive, and industrial electronics.
Package
SM4T18AY comes in an SMB package (DO-214AA).
