STMicroelectronics SMC50J70A

Overview

SMC50J70A from STMicroelectronics is a unidirectional 70 V standoff voltage transient voltage suppressor (TVS) diode in SMC package, rated for 5000 W peak pulse power (10/1000 μs), 640 A peak pulse current, and clamping voltage of 113 V at 640 A - designed for primary-level surge protection on DC power rails and signal lines in industrial motor drives and telecom power supplies.

For engineers reviewing the SMC50J70A datasheet, SMC50J70A pinout, SMC50J70A application, or SMC50J70A equivalent, key selection criteria include its 70 V working voltage, low 0.2 µA leakage at 25 °C, 175 °C junction temperature rating, JEDEC-registered SMC package compatibility, and IEC 61000-4-2 ±30 kV ESD robustness.

Technical Context

This planar-junction TVS diode operates as a clamping device triggered by reverse-biased avalanche breakdown above 77.9 V (min V_BR), with dynamic resistance of 174 mΩ enabling precise voltage limiting during 8/20 μs surges up to 146 A. Its thermal design supports continuous operation up to T_j = 175 °C, validated per JESD22-B102 E3 and MIL-STD-750 Method 2026.

The device complies with IEC 61000-4-4 Level 4 (4 kV), exceeds IEC 61000-4-2 Level 4 (±30 kV air/contact discharge), and maintains stable clamping performance across temperature via α_T = 10.5 × 10⁻⁴/°C voltage drift coefficient - critical for high-reliability power entry and interface protection where leakage and thermal stability are design constraints.

Key Specifications

Pinout & Package

SMC50J70A uses the JEDEC-registered SMC (DO-214AB) surface-mount package: 7.75–8.15 mm length, 5.55–6.25 mm width, 2.45 mm max height, matte tin-plated leads, MSL Level 1, compatible with IPC-7531 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ70A and 1.5KE70A, SMC50J70A uniquely delivers 5000 W surge handling in an SMT-optimized SMC package with superior thermal derating (175 °C) and tighter clamping (113 V), making it the only option qualified for high-reliability industrial power entry protection requiring both high energy and automated manufacturing.

Availability

SMC50J70A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, smart grid meters, and EV charging stations requiring stable component supply, full traceability, and long-lifecycle support.

Supply support for SMC50J70A 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

SMC50J TVS series belongs to ST's high-power transient protection product line, engineered specifically for robust front-end surge immunity in harsh-environment power systems where reliability, thermal resilience, and standardized packaging are mandatory.

FAQ

What is the maximum clamping voltage of SMC50J70A under a 10/1000 μs surge?

The maximum clamping voltage (V_CL) of SMC50J70A is 113 V at 640 A for a 10/1000 μs waveform, measured at T_j = 25 °C per Table 2 of DS13845 Rev 1. This value increases with junction temperature at a rate of 10.5 × 10⁻⁴/°C, reaching ~122 V at T_j = 125 °C.

Is SMC50J70A suitable for bidirectional signal line protection?

No - SMC50J70A is a unidirectional TVS diode, intended for DC rail protection with cathode-to-line orientation. For bidirectional signal line protection, ST offers the SMC50J70CA variant, which provides symmetrical clamping for AC or data lines subject to polarity-agnostic transients.

Does SMC50J70A meet lead-free and RoHS requirements?

Yes - SMC50J70A features matte tin-plated leads and conforms to ST's ECOPACK2 environmental standard, satisfying RoHS Directive 2011/65/EU and JEDEC J-STD-020 MSL Level 1 moisture sensitivity classification for lead-free reflow compatibility.

How does the 174 mΩ dynamic resistance impact circuit protection performance?

The 174 mΩ dynamic resistance (R_D) directly determines voltage overshoot during surge events: V_CL = V_BR + R_D × I_PP. At 640 A, this contributes 111.4 V to clamping - confirming the 113 V spec reflects tight control over parasitic resistance, essential for protecting sensitive 75 V-rated ICs in power conversion stages.