Vishay General Semiconductor - Diodes Division SM6T39CA-E3/52

Overview

SM6T39CA-E3/52 from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMB (DO-214AA) package, designed for clamping ESD and surge transients on signal/power lines. It features 39 V breakdown voltage (V_BR = 37.1–41.0 V at 1 mA), 53.9 V maximum clamping voltage (V_C) at 11.1 A peak pulse current (10/1000 μs), and 600 W peak pulse power rating. Used to protect automotive sensor interfaces and industrial I/O lines against inductive switching surges.

For engineers reviewing the SM6T39CA-E3/52 datasheet, SM6T39CA-E3/52 pinout, SM6T39CA-E3/52 application, or SM6T39CA-E3/52 equivalent, key selection criteria include bidirectional clamping capability, SMB footprint compatibility, AEC-Q101 qualification status (not applicable to this E3 suffix variant), junction temperature range (–65 °C to +150 °C), and low-inductance design for fast transient response.

Technical Context

This bidirectional TVS operates symmetrically across both polarities, with identical V_BR, V_WM, and V_C specifications in forward and reverse directions. Its glass-passivated junction ensures stable leakage (<1 μA at 33.3 V stand-off) and robust surge handling under repetitive transients.

The device uses a low-inductance SMB (DO-214AA) package with matte tin-plated leads compliant to J-STD-002 and JESD 22-B102. Thermal resistance is R_θJA = 100 °C/W (typ.) and R_θJL = 20 °C/W (typ.), enabling reliable operation up to T_J = 150 °C with appropriate PCB copper pad layout (0.2" × 0.2").

Key Specifications

Pinout & Package

SMB (DO-214AA) package: molded plastic case with two coplanar terminals; no polarity marking for bidirectional types; meets UL 94 V-0 flammability rating; terminals are matte tin plated and solderable per J-STD-002.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with SMAJ39CA and 1.5KE39CA, SM6T39CA-E3/52 delivers optimal balance of 600 W surge capacity, low-profile SMB packaging, and tight 53.9 V clamping-making it preferred for space-constrained, high-reliability SMT designs requiring precise voltage limiting.

Availability

SM6T39CA-E3/52 is available at Aetrix Electronics and suitable for automotive sensor protection, industrial I/O interface hardening, and telecom line card surge suppression requiring stable component supply, RoHS-compliant commercial-grade sourcing, and consistent tape-and-reel delivery.

Supply support for SM6T39CA-E3/52 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.

The SM6T Series is engineered for high-energy transient suppression in compact SMT formats, targeting automotive, industrial, and consumer electronics where robustness, low inductance, and AEC-Q101-ready variants are critical.

FAQ

What is the breakdown voltage tolerance for SM6T39CA-E3/52?

The SM6T39CA-E3/52 has a specified breakdown voltage range of 37.1 V to 41.0 V at 1 mA test current, representing ±5.5% tolerance around the nominal 39 V rating. This tight V_BR window ensures predictable clamping behavior in bidirectional surge events and aligns with IEC 61000-4-5 compliance requirements for system-level immunity testing. The SM6T39CA-E3/52 maintains this specification across its full operating temperature range.

Is SM6T39CA-E3/52 qualified to AEC-Q101?

No, SM6T39CA-E3/52 is not AEC-Q101 qualified. It carries the "E3" suffix indicating RoHS-compliant commercial grade. AEC-Q101 qualified versions use "HE3" or "HM3" suffixes (e.g., SM6T39CAHE3_B). The SM6T39CA-E3/52 meets all electrical and mechanical specifications of the SM6T family but lacks the extended reliability testing required for automotive qualification. For automotive applications, specify SM6T39CAHE3_B instead of SM6T39CA-E3/52.

What is the maximum clamping voltage of SM6T39CA-E3/52 under surge conditions?

The SM6T39CA-E3/52 exhibits a maximum clamping voltage (V_C) of 53.9 V when subjected to an 11.1 A peak pulse current with a 10/1000 μs waveform. This value is measured per Figure 1 in the Vishay datasheet 88385 and represents the upper limit of voltage seen by protected circuitry during worst-case transient events. The SM6T39CA-E3/52 achieves this clamping performance while maintaining low leakage (<1 μA at 33.3 V) during normal operation.

Can SM6T39CA-E3/52 be used in place of a unidirectional TVS like SM6T39A-E3/52?

No-SM6T39CA-E3/52 is strictly bidirectional and cannot replace unidirectional SM6T39A-E3/52 in circuits requiring polarity-sensitive clamping, such as DC power rail protection where forward conduction must be blocked. The "CA" suffix denotes symmetrical breakdown in both directions, whereas "A" indicates unidirectional operation with cathode band marking. Substituting SM6T39CA-E3/52 for SM6T39A-E3/52 may cause unintended conduction in forward bias. Always verify circuit topology before interchanging SM6T39CA-E3/52 and SM6T39A-E3/52.

What is the thermal resistance of SM6T39CA-E3/52 and how does it affect PCB layout?

The SM6T39CA-E3/52 has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W and junction-to-lead (R_θJL) of 20 °C/W when mounted on 0.2" × 0.2" copper pads per terminal. To maintain safe junction temperatures under sustained power dissipation, PCB layout must provide adequate copper area and thermal vias-especially critical when operating near the 5.0 W steady-state power limit. The SM6T39CA-E3/52's thermal performance is optimized for standard SMB land patterns defined in the Vishay package outline drawing.