Taiwan Semiconductor Corporation SMCJ85

Overview

SMCJ85 from Taiwan Semiconductor is a unidirectional 1500W surface-mount transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, with 85V working stand-off voltage (VWM), 94.4–115V breakdown voltage (VBR), and 151V maximum clamping voltage (VC) at 10.4A peak pulse current - designed for automotive power line and industrial control board surge protection.

For engineers reviewing the SMCJ85 datasheet, SMCJ85 pinout, SMCJ85 application, or SMCJ85 equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, junction temperature limits (−55°C to +150°C), moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on high-reliability PCBs.

Technical Context

The SMCJ85 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR range (94.4–115V @ IT = 1mA); it clamps transients to ≤151V within <1.0ps response time, limiting energy dissipation via 1500W peak pulse power rating at tp = 1ms.

Its thermal design relies on low junction-to-case resistance (RθJC = 10°C/W) and junction-to-ambient resistance (RθJA = 55°C/W), enabling stable operation up to TJ = 150°C; steady-state power dissipation is rated at 5W, with forward voltage VF = 3.5V @ IF = 100A (per family specification for SMCJ5.0–SMCJ90 devices).

Key Specifications

Pinout & Package

DO-214AB (SMC) package: molded plastic case with matte tin-plated leads, cathode band marking polarity; compliant with UL 94V-0 flammability and JESD201 Class 2 whisker resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ85A, SMCJ85 delivers double the surge current capacity and higher system-level robustness; versus 1.5SMC85A, it provides equivalent protection with Taiwan Semiconductor's qualification for extended temperature cycling and moisture resistance (MSL 1).

Availability

SMCJ85 is available at Aetrix Electronics and suitable for automotive power distribution, industrial PLC I/O modules, LED lighting drivers, and medical diagnostic equipment requiring stable component supply and full ISO 7637-2 compliance.

Supply support for SMCJ85 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, MOSFETs, and power management components.

The SMCJ series belongs to TSC's high-power surface-mount TVS portfolio, engineered specifically for automotive and industrial applications demanding ruggedized surge immunity, AEC-Q200 alignment, and long-term parametric stability under thermal cycling.

FAQ

What is the clamping voltage of SMCJ85 and how is it measured?

The SMCJ85 has a maximum clamping voltage (VC) of 151 V, measured at a peak pulse current (IPPM) of 10.4 A with a 10/1000 μs waveform per Fig.5 in the datasheet. This value represents the worst-case voltage imposed on the protected circuit during standardized surge testing and is guaranteed across the full operating temperature range (−55°C to +150°C). The SMCJ85 maintains this clamping performance due to its low dynamic impedance and glass-passivated junction structure.

Is SMCJ85 unidirectional or bidirectional, and how is polarity identified?

The SMCJ85 is a unidirectional TVS diode, intended for DC line protection where reverse voltage is not expected. Polarity is marked by a cathode band on the DO-214AB (SMC) package body; the banded end connects to the protected line (e.g., 12V rail), while the anode connects to ground. Bidirectional variants use "CA" suffix (e.g., SMCJ85CA), which SMCJ85 does not carry - confirming its unidirectional function.

Does SMCJ85 meet automotive surge immunity standards such as ISO 7637-2?

Yes, the SMCJ85 explicitly meets ISO 7637-2 test pulses 1, 2a, 2b, 3a, and 3b per the manufacturer's documentation. Its 1500W peak power rating, fast <1.0 ps response time, and clamping behavior under defined waveforms enable direct implementation in automotive ECUs, body control modules, and infotainment power supplies without additional filtering components - a key validation point confirmed in Taiwan Semiconductor's S2104 datasheet revision.

What is the maximum steady-state power dissipation for SMCJ85?

The SMCJ85 has a steady-state power dissipation (PD) rating of 5 W at TA = 25°C, as specified in the Absolute Maximum Ratings table. This value applies only to continuous DC or low-frequency reverse bias conditions - not transient events. In normal operation, reverse leakage remains ≤1 μA at 85 V, resulting in negligible static power loss (<85 μW); the 5 W rating primarily supports short-duration overload scenarios outside surge conditions.

Can SMCJ85 be used in automated SMT assembly processes without special handling?

Yes, the SMCJ85 is qualified for automated placement and reflow soldering per J-STD-002, with matte tin-plated leads and MSL Level 1 rating - meaning unlimited floor life and no bake requirement prior to assembly. Its DO-214AB (SMC) package geometry and weight (0.210 g) are optimized for pick-and-place accuracy, and the device complies with JEDEC standards for thermal shock and solder wetting, making it fully compatible with standard high-volume SMT lines.