STMicroelectronics SMC30J28CA

Overview

SMC30J28CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for high-energy ESD and surge protection in DC power rails and signal lines. It features a standoff voltage (VRM) of 28 V, clamping voltage (VCL) of 45.4 V at 168 A (10/1000 µs), peak pulse power of 3000 W, and operates up to 175 °C junction temperature - deployed in industrial power supplies and telecom interface circuits.

For engineers reviewing the SMC30J28CA datasheet, SMC30J28CA pinout, SMC30J28CA application, or SMC30J28CA equivalent, key selection criteria include bidirectional ESD robustness (±30 kV contact/air per IEC 61000-4-2), low leakage (0.2 µA at 25 °C), JEDEC-standard SMC package compatibility, and thermal stability across extended temperature ranges.

Technical Context

This planar-junction TVS diode uses silicon avalanche technology to provide fast-response clamping during transient events. Its bidirectional architecture enables symmetrical protection on AC-coupled or floating lines without polarity constraints, and its low dynamic resistance (RD = 41.4 mΩ) ensures minimal voltage overshoot under high-current surges.

The device complies with IEC 61000-4-2 Level 4 (±30 kV), IEC 61000-4-4 Level 4 (4 kV), and MIL-STD-883 Method 3015. Its thermal design supports continuous operation at Tj = 175 °C, validated by JESD22-A103 and J-STD-020 MSL Level 1 reflow compatibility.

Key Specifications

Pinout & Package

SMC30J28CA is housed in a JEDEC-standard SMC (DO-214AB) surface-mount package with matte tin-plated leads. The bidirectional configuration requires no anode/cathode orientation - both terminals are functionally symmetric for AC or floating-line protection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMC30J28CA, SMBJ28CA offers smaller footprint but insufficient energy handling for industrial power rails, while SAC28CA matches power rating but delivers less precise voltage limiting - making SMC30J28CA optimal for designs demanding tight clamping control at full 3000 W capability.

Availability

SMC30J28CA is available at Aetrix Electronics and suitable for industrial power input protection, telecom line interface, automotive body control modules, and medical sensor interfaces requiring stable component supply and long-term lifecycle support.

Supply support for SMC30J28CA 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 power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The SMC30J TVS series targets high-reliability surge protection in harsh environments, emphasizing thermal resilience, ESD robustness, and JEDEC-compliant manufacturability for mission-critical power and interface circuits.

FAQ

What is the maximum clamping voltage of SMC30J28CA under a 10/1000 µs surge?

The maximum clamping voltage (VCL) is 45.4 V at 168 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature at a coefficient of 10.8 × 10⁻⁴/°C, reaching approximately 48.1 V at Tj = 125 °C per the datasheet's αT correction formula.

Is SMC30J28CA compatible with lead-free reflow soldering?

Yes - it meets J-STD-020 MSL Level 1 and is qualified for lead-free reflow with a peak temperature of 240–245 °C for 20–40 seconds. The recommended profile includes ramp-up at ≤3 °C/s, soak at 150–200 °C for 60–120 s, and controlled cooling at ≤6 °C/s.

How does the bidirectional configuration affect PCB layout?

The bidirectional structure eliminates polarity marking - both terminals are electrically symmetric. Layout requires no orientation check during placement, simplifying automated assembly and enabling use on AC-coupled traces, transformer-isolated lines, or differential buses like RS-485 without directional routing constraints.

Can SMC30J28CA replace unidirectional TVS diodes in existing designs?

No - it cannot directly replace unidirectional types (e.g., SMC30J28A) in DC-biased circuits because its symmetrical breakdown allows conduction in both directions. Doing so may cause unintended forward conduction or short-circuit behavior on polarized rails unless circuit topology explicitly supports bidirectional clamping.