STMicroelectronics SMC50J26CA

Overview

SMC50J26CA 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 delivers 5000 W peak pulse power (10/1000 µs), clamps at 42.1 V (max) under 119 A surge current, and operates up to 175 °C junction temperature - enabling robust protection in automotive infotainment power supplies, industrial PLC I/O modules, and telecom base station front-ends.

For engineers reviewing the SMC50J26CA datasheet, SMC50J26CA pinout, SMC50J26CA application, or SMC50J26CA equivalent, key selection criteria include its 26 V standoff voltage, bidirectional polarity, low 0.2 µA leakage at 25 °C, JEDEC-standard SMC package compatibility, and IEC 61000-4-2 (±30 kV contact/air) and IEC 61000-4-4 (4 kV level 4) compliance - all critical for high-reliability overvoltage hardening.

Technical Context

This planar-junction TVS diode uses avalanche breakdown to clamp transient voltages across its terminals within nanoseconds. Its bidirectional structure provides symmetrical clamping for AC-coupled or floating lines, with dynamic resistance of 30.2 mΩ at 8/20 µs pulses - ensuring minimal voltage overshoot during fast transients like lightning-induced surges.

The device's thermal design supports continuous operation at T_j = 175 °C, validated by JEDEC JESD22-A104 thermal cycling and J-STD-020 MSL Level 1 moisture sensitivity rating. Its low leakage (<0.2 µA at V_RM = 26 V, 25 °C) prevents system-level standby current degradation in battery-powered edge sensors.

Key Specifications

Pinout & Package

SMC50J26CA is housed in a JEDEC-standard SMC (DO-214AB) surface-mount package with matte tin-plated leads, compatible with IPC-7531 footprints and reflow profiles per J-STD-020. The package measures 5.55–6.25 mm × 7.75–8.15 mm × 2.45 mm max height and weighs 264 mg.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMC50J26CA, SMBJ26CA offers smaller footprint but insufficient surge capacity for 24 V power rail hardening, while SAC26CA trades tighter clamping for broader second-source availability - making SMC50J26CA optimal for high-energy, high-reliability industrial and automotive deployments.

Availability

SMC50J26CA is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial programmable logic controllers, and telecom base station power management requiring stable component supply across extended product lifecycles.

Supply support for SMC50J26CA 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, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The SMC50J TVS series targets high-reliability overvoltage protection in harsh environments - specifically engineered for 24 V/48 V DC systems needing IEC 61000-4-2/4-4 compliance and extended temperature operation.

FAQ

What is the maximum clamping voltage for SMC50J26CA under a 10/1000 µs surge?

The maximum clamping voltage (V_CL) is 42.1 V at 119 A for a 10/1000 µs waveform, measured at T_j = 25 °C. This value increases with junction temperature per α_T = 10⁻⁴/°C, reaching ~45.2 V at T_j = 125 °C using the datasheet formula V_CL(T_j) = V_CL(25 °C) × [1 + α_T × (T_j − 25)].

How does SMC50J26CA differ from unidirectional SMC50J26A?

SMC50J26CA is bidirectional with symmetrical clamping in both polarities, marked with a cathode bar but electrically identical on both terminals. SMC50J26A is unidirectional, conducting only in reverse bias - making CA suitable for AC or floating lines (e.g., RS-485), while A is used for DC rail protection with defined polarity.

Can SMC50J26CA be used in parallel for higher surge current handling?

No - paralleling TVS diodes is not recommended due to mismatched dynamic resistance and avalanche turn-on characteristics, which cause current imbalance and potential thermal runaway. For >119 A surge capability, select a higher-rated part (e.g., SMC50J30CA) or use staged protection with upstream current-limiting resistors.

What is the thermal resistance junction-to-ambient for SMC50J26CA on a standard FR4 PCB?

On a 70 µm copper FR4 board with the recommended footprint (5.11 mm × 8.19 mm pad area), R_th(j-a) is 100 °C/W for a single pulse. With 2 cm² total copper area under both leads, it improves to ~40 °C/W - enabling sustained 175 °C operation without external heatsinking in typical industrial layouts.