STMicroelectronics SMB6F6.5A

Overview

SMB6F6.5A from STMicroelectronics is a unidirectional 600 W transient voltage suppression (TVS) diode in SMB Flat package, designed for surge protection of sensitive electronics. It features a stand-off voltage of 6.5 V, clamping voltage of 11.2 V at 56 A (10/1000 µs), and low leakage current (20 nA at 25 °C, 50 nA at 85 °C), enabling reliable operation in automotive power line and industrial I/O interface protection.

For engineers reviewing the SMB6F6.5A datasheet, SMB6F6.5A pinout, SMB6F6.5A application, or SMB6F6.5A equivalent, key selection criteria include clamping performance under 10/1000 µs surges, junction temperature derating up to +175 °C, dynamic resistance (0.057 Ω), and compliance with IEC 61000-4-2 level 4 (±30 kV contact/air discharge).

Technical Context

This TVS diode uses planar silicon technology to achieve low leakage (<50 nA at 85 °C) and high thermal stability across –55 °C to +175 °C operating junction temperature. Its unidirectional configuration provides asymmetric clamping optimized for DC-biased lines such as 5 V or 12 V power rails.

The device delivers 600 W peak pulse power (10/1000 µs) at 25 °C, derating to 470 W at T_j = 175 °C. Its dynamic resistance of 0.057 Ω ensures minimal voltage overshoot during fast transients, while IEC 61000-4-4 level 4 (±4 kV) and ISO 10605 ESD robustness support harsh industrial and automotive environments.

Key Specifications

Pinout & Package

SMB6F6.5A is housed in an SMB Flat package (JEDEC DO-214AA), measuring 3.95 mm × 5.60 mm × 1.10 mm with matte tin-plated leads and IPC7531-compliant footprint. The flat profile (1 mm height) enables low-profile PCB mounting in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ6.5A and P6SMB6.5A, SMB6F6.5A offers superior thermal derating (470 W at 175 °C), lower dynamic resistance (0.057 Ω), and verified IEC 61000-4-2 level 4 performance-making it optimal for automotive and industrial designs demanding robust, temperature-stable clamping.

Availability

SMB6F6.5A is available at Aetrix Electronics and suitable for automotive power line protection, industrial digital I/O protection, USB port ESD protection, and DC-DC converter input protection requiring stable component supply across extended temperature ranges and high-reliability surge environments.

Supply support for SMB6F6.5A 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 innovative solutions across automotive, industrial, power, and smart mobility markets with strong IP and manufacturing vertical integration.

The SMB6FxxA series belongs to ST's high-reliability TVS portfolio, engineered specifically for robust transient suppression in automotive and industrial applications where long-term stability, low leakage, and high-temperature operation are mandatory.

FAQ

What is the maximum clamping voltage of SMB6F6.5A under a 10/1000 µs surge?

The maximum clamping voltage (V_CL) is 11.2 V at 56 A for a 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases with junction temperature due to the positive temperature coefficient (α_T = 6.1 × 10⁻⁴/°C), reaching ~12.1 V at T_j = 125 °C per datasheet calculation.

Is SMB6F6.5A suitable for bidirectional signal line protection?

No - SMB6F6.5A is unidirectional and intended for DC-biased lines like power rails. For bidirectional protection (e.g., RS-485, USB D+/D−), a symmetric TVS such as SMB6F6.5CA or SMAJ6.5CA is required; using this part on AC-coupled or floating signals risks forward conduction and improper clamping.

Does SMB6F6.5A require special PCB layout considerations?

Yes - minimize trace inductance by placing it directly across the protected line and ground with short, wide copper pours. Use the recommended IPC7531 footprint (5.84 mm × 1.20 mm pad pitch), ensure ≥1 cm² copper area under each lead for thermal dissipation, and avoid vias in high-current paths to maintain low dynamic resistance performance.

How does SMB6F6.5A compare to SMA-package TVS diodes in surge handling?

SMB6F6.5A delivers identical 600 W peak power (10/1000 µs) as SMA equivalents but in a lower-profile package (1.1 mm vs. 2.3 mm height). Its planar construction yields lower leakage and better thermal stability than many SMA devices, though its 56 A IPP is slightly lower than SMAJ6.5A (61 A), reflecting trade-offs between size, thermal mass, and surge current capacity.