STMicroelectronics SM6T24A

Overview

SM6T24A from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode in SMB package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4). It features 24 V nominal breakdown voltage (V_BR = 22.8–25.2 V), 33.2 V clamping voltage at 1 A (10/1000 µs), and low leakage current (0.2 µA @ 25 °C). It protects MOSFETs, signal lines, and ICs in industrial power supplies and automotive body electronics.

For engineers reviewing the SM6T24A datasheet, SM6T24A pinout, SM6T24A application, or SM6T24A equivalent, this page delivers verified electrical parameters, SMB package layout, real-world clamping behavior under 10/1000 µs and 8/20 µs transients, thermal derating curves, and direct alternatives with documented V_CL, I_PP, and R_D differences.

Technical Context

The SM6T24A uses planar silicon junction technology to achieve stable V_BR temperature coefficient (α_T = 9.4 × 10⁻⁴/°C) and low dynamic resistance (R_D = 0.444 Ω at 10/1000 µs). Its unidirectional configuration enables asymmetric clamping-forward conduction only during reverse overvoltage events-making it suitable for DC-biased signal and power rails.

It operates across −55 °C to +150 °C junction temperature, with peak pulse power derating to 350 W at T_j = 150 °C (10/1000 µs). Compliance with UL497B (file E136224) confirms its qualification as an isolated loop circuit protector for telecom and industrial interfaces.

Key Specifications

Pinout & Package

The SM6T24A is housed in an SMB (DO-214AA) surface-mount package measuring 3.3–3.95 mm × 5.1–5.6 mm × 1.9–2.45 mm (L × W × H), with matte tin-plated leads compliant with J-STD-002 and JEDEC MO-136.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SM6T24A, SMBJ24A offers higher V_BR tolerance but sacrifices clamping tightness, while P6SMB24A matches mechanical compatibility but trades off leakage performance-making SM6T24A optimal for low-leakage, high-reliability 24 V industrial interfaces.

Availability

SM6T24A is available at Aetrix Electronics and suitable for industrial power supply input protection, automotive body control module signal lines, telecom interface surge protection, and industrial motor drive gate driver protection requiring stable component supply and full traceability.

Supply support for SM6T24A 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, delivering intelligent power, sensing, and connectivity solutions for automotive, industrial, and consumer markets.

The SM6T series belongs to ST's transient protection portfolio, engineered specifically for high-reliability DC rail and signal-line protection in harsh environments where low leakage, high T_j, and certified surge immunity are mandatory.

FAQ

What is the maximum clamping voltage of SM6T24A under a 10/1000 µs surge?

The SM6T24A clamps to 33.2 V when subjected to a 1 A 10/1000 µs transient, as specified in Table 2 of DS0684 Rev 15. This value is measured at T_amb = 25 °C and scales with junction temperature using α_T = 9.4 × 10⁻⁴/°C. At 150 °C, V_CL rises to approximately 35.1 V.

Can SM6T24A be used in bidirectional signal lines like RS-485?

No-SM6T24A is unidirectional and only clamps reverse-biased overvoltages. For bidirectional lines such as RS-485, the bidirectional variant SM6T24CA must be used. Using SM6T24A on AC-coupled or differential lines risks forward conduction during normal signal swings, causing distortion or latch-up.

How does SM6T24A's leakage current compare to other 24 V TVS diodes?

At 20.5 V reverse bias and 25 °C, SM6T24A draws only 0.2 µA-significantly lower than typical SMB-class alternatives (e.g., P6SMB24A: 1 µA). This enables use in high-impedance sensor bias networks and battery-powered IoT nodes where quiescent current must remain below 1 µA.

Is SM6T24A compatible with lead-free reflow soldering processes?

Yes-SM6T24A is qualified for lead-free reflow per J-STD-020 MSL level 1, with a peak reflow temperature of 240–245 °C for ≤60 seconds. Its matte tin-plated leads meet JESD 22-B102 E3 and MIL-STD-750 method 2026, ensuring robust wetting and intermetallic formation without whisker growth.