Vishay General Semiconductor - Diodes Division SMCJ8.5CA-M3/57T

Overview

SMCJ8.5CA-M3/57T from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for clamping voltage transients on signal or power lines. It features a 8.5 V stand-off voltage (VWM), 14.4 V maximum clamping voltage (VC) at 104.2 A peak pulse current (IPPM), and 1500 W peak pulse power (PPPM) with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power supplies.

For engineers reviewing the SMCJ8.5CA-M3/57T datasheet, SMCJ8.5CA-M3/57T pinout, SMCJ8.5CA-M3/57T application, or SMCJ8.5CA-M3/57T equivalent, key selection criteria include bidirectional clamping capability, halogen-free RoHS compliance (M3 suffix), 1500 W surge rating, junction temperature range of –55 °C to +150 °C, and compatibility with automated SMT placement on 8.0 mm × 8.0 mm copper pads.

Technical Context

The SMCJ8.5CA-M3/57T operates as a bidirectional avalanche diode, symmetrically clamping transient overvoltages in both polarities without polarity marking. Its glass-passivated junction ensures stable breakdown behavior and low incremental surge resistance under repetitive 10/1000 μs surges.

It meets MSL Level 1 per J-STD-020 with 260 °C lead-free reflow peak, supports 6.5 W steady-state power dissipation at TA = 50 °C, and exhibits a typical thermal resistance of 75 °C/W (junction-to-ambient) when mounted on minimum recommended pad layout.

Key Specifications

Pinout & Package

SMCJ8.5CA-M3/57T uses the SMC (DO-214AB) package: a two-terminal, bidirectional device with no polarity marking. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102, and meet JESD 201 Class 2 whisker test requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ8.5CA-M3/57T, SMAJ8.5CA-E3/61 trades surge robustness for size, while SMCJ8.5CAHE3_A/H adds automotive qualification without altering clamping performance - making the original ideal for cost-sensitive industrial designs requiring 1500 W immunity and halogen-free compliance.

Availability

SMCJ8.5CA-M3/57T is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface protection, telecom line interface protection, and consumer USB port surge suppression requiring stable component supply and full traceability.

Supply support for SMCJ8.5CA-M3/57T 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 and application-specific performance.

The SMCJ series targets high-energy transient suppression in harsh environments, engineered for automotive, industrial, and telecom systems where robustness, consistency, and regulatory compliance are non-negotiable.

FAQ

What is the clamping voltage of SMCJ8.5CA-M3/57T at its rated peak pulse current?

The SMCJ8.5CA-M3/57T has a maximum clamping voltage (VC) of 14.4 V when subjected to its rated peak pulse current (IPPM) of 104.2 A using a 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during surge events. The SMCJ8.5CA-M3/57T maintains this clamping performance across its full operating temperature range.

Is SMCJ8.5CA-M3/57T suitable for automotive applications?

The SMCJ8.5CA-M3/57T is halogen-free and RoHS-compliant (M3 suffix) but is not AEC-Q101 qualified. For non-safety-critical automotive subsystems like infotainment power rails or lighting control, it provides robust 1500 W surge protection. However, for ADAS, powertrain, or body control modules requiring formal qualification, the AEC-Q101 variant SMCJ8.5CAHE3_A/H must be selected instead of the SMCJ8.5CA-M3/57T.

What does the "CA" suffix indicate in SMCJ8.5CA-M3/57T?

The "CA" suffix in SMCJ8.5CA-M3/57T denotes a bidirectional configuration - meaning the device clamps transient overvoltages equally in both polarities, with identical breakdown and clamping characteristics in forward and reverse directions. Unlike unidirectional "A" variants, the CA version has no cathode band marking and is used where signal lines lack defined polarity or carry AC-coupled signals.

How is thermal performance affected by PCB layout for SMCJ8.5CA-M3/57T?

Thermal performance of the SMCJ8.5CA-M3/57T depends critically on copper pad area: the datasheet specifies 0.31″ × 0.31″ (8.0 mm × 8.0 mm) pads per terminal for rated 6.5 W power dissipation at TA = 50 °C. Reducing pad size increases RθJA beyond the typical 75 °C/W, risking thermal runaway during sustained surges. The SMCJ8.5CA-M3/57T must be placed outside thermally congested zones and avoid proximity to other heat sources.

Can SMCJ8.5CA-M3/57T replace SMCJ8.0CA-M3/57T in an existing design?

Yes, the SMCJ8.5CA-M3/57T can directly replace SMCJ8.0CA-M3/57T in most cases: both share identical SMC package, bidirectional functionality, 1500 W PPPM rating, and thermal characteristics. The only difference is a 0.5 V higher VWM (8.5 V vs. 8.0 V) and slightly higher VBR (9.44–10.4 V vs. 8.89–9.83 V), which may improve noise immunity but requires verification that protected circuitry tolerates the higher stand-off voltage. No PCB changes are needed for the SMCJ8.5CA-M3/57T swap.