STMicroelectronics SM30T23CAY

Overview

SM30T23CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMC package, designed for ISO 7637-2 pulse protection in 12 V/24 V vehicle systems. It delivers 3000 W peak pulse power (10/1000 µs), clamps at 32.4 V (max) under 93 A surge, and operates up to 175 °C junction temperature - deployed in engine control units, body control modules, and infotainment power rails.

For engineers reviewing the SM30T23CAY datasheet, SM30T23CAY pinout, SM30T23CAY application, or SM30T23CAY equivalent, key selection criteria include bidirectional clamping capability, low leakage (0.2 µA @ 25 °C), AEC-Q101 qualification, and compliance with ISO 10605 (±30 kV ESD), ISO 7637-2 (Pulse 1/2a/3a/3b), and IEC 61000-4-4 Level 4.

Technical Context

This TVS diode uses planar silicon technology to achieve stable breakdown voltage (22.2–24.6 V), low dynamic resistance (24.4 mΩ), and minimal capacitance - critical for high-speed CAN/LIN bus protection without signal distortion. Its bidirectional architecture enables symmetrical clamping across both polarities, supporting robust protection against load dump transients and reverse-battery events.

The device meets stringent automotive reliability requirements: operating junction temperature range of –55 °C to +175 °C, JEDEC-registered SMC package with matte tin lead finish, and full compliance with J-STD-020 MSL Level 1, UL94 V0, and ISO 16750-2 Test B. Thermal impedance is optimized for PCB copper area ≥3.5 cm².

Key Specifications

Pinout & Package

SM30T23CAY is housed in a JEDEC-registered SMC (DO-214AB) surface-mount package measuring 7.75–8.15 mm × 5.55–6.25 mm × 2.45 mm max, with matte tin-plated leads and IPC-7531-compliant footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ24CA and SMBJ24CA, SM30T23CAY provides 5× higher surge power handling, 6.5 V lower clamping voltage at rated current, and AEC-Q101 validation - making it the sole drop-in solution for ISO 7637-2-compliant 12 V automotive power rails.

Availability

SM30T23CAY is available at Aetrix Electronics and suitable for engine control units, body control modules, and infotainment power supplies requiring stable component supply across extended automotive production lifecycles.

Supply support for SM30T23CAY 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 automotive, industrial, and power management solutions with vertical manufacturing and design expertise.

SM30T23CAY belongs to the SM30TY series of AEC-Q101-qualified TVS diodes engineered specifically for ISO 7637-2 and ISO 10605 compliance in harsh automotive environments - targeting long-term reliability in under-hood and chassis-mounted electronics.

FAQ

What is the maximum clamping voltage of SM30T23CAY at 93 A?

The maximum clamping voltage (V_CL) is 32.4 V under 10/1000 µs waveform at 93 A peak pulse current, measured at T_amb = 25 °C. This value increases linearly with junction temperature using α_T = 10⁻⁴/°C, reaching ~34.1 V at T_j = 125 °C per datasheet Equation 2.

Is SM30T23CAY suitable for protecting CAN FD interfaces?

Yes - its bidirectional configuration, low dynamic resistance (24.4 mΩ), and <35 pF typical junction capacitance (per Figure 8) preserve signal integrity up to 5 Mbps. It is validated for ISO 10605 ±30 kV ESD and ISO 7637-2 Pulse 3b (150 V), making it appropriate for CAN FD transceiver I/O protection when placed within 2 cm of the connector.

How does SM30T23CAY differ from unidirectional SM30T23AY?

SM30T23CAY is bidirectional (marked "3BAKY"), providing symmetrical clamping for both positive and negative transients across the same terminals. SM30T23AY is unidirectional (marked "3AAKY") and must be oriented with cathode toward the protected rail - limiting use to single-polarity protection like 12 V supply lines, not differential buses.

What PCB layout practices maximize thermal performance?

To maintain T_j ≤ 175 °C, use ≥3.5 cm² of 70 µm copper per lead (per Figure 12), place the device near board edges for airflow, avoid thermal vias under the center pad (SMC has no exposed pad), and ensure solder mask openings match the recommended footprint (8.19 mm × 5.11 mm). Thermal impedance drops from 100 °C/W (no copper) to 40 °C/W with optimal layout.