Microchip Technology SMAJ8.5CE3/TR13

Overview

SMAJ8.5CE3/TR13 from Microsemi is a surface-mount bidirectional 500 W transient voltage suppressor (TVS) designed for clamping ESD, EFT, and lightning-induced surges in power and signal lines. It features a reverse standoff voltage of 8.5 V, minimum breakdown voltage of 9.44 V at 1 mA, clamping voltage of 15.9 V at 31.4 A peak pulse current, and operates from –65 °C to +150 °C - used in industrial I/O protection and DC power rail surge suppression.

For engineers reviewing the SMAJ8.5CE3/TR13 datasheet, SMAJ8.5CE3/TR13 pinout, SMAJ8.5CE3/TR13 application, or SMAJ8.5CE3/TR13 equivalent, key selection criteria include bidirectional clamping capability, 500 W 10/1000 µs surge rating, RoHS-compliant matte-tin plating, DO-214AC package compatibility, and IEC61000-4-2/4-4/4-5 compliance for system-level ESD, fast transient, and secondary lightning protection.

Technical Context

This bidirectional TVS diode uses silicon avalanche junction technology to provide symmetrical clamping in both polarities, enabling protection of AC-coupled or floating signal paths without polarity constraints. Its <100 ps theoretical response time ensures sub-nanosecond turn-on for ESD events, while the 15.9 V clamping voltage at 31.4 A defines the maximum voltage seen by downstream circuitry during a standardized 10/1000 µs surge.

The device is rated for 500 W peak pulse power per IEC61000-4-5 with 42 Ω source impedance (Class 4), supports 100% temperature cycling screening (–55 °C to +125 °C, 10×), and exhibits ≤1 µA standby leakage at 8.5 V - critical for low-power sensor interfaces and battery-backed systems.

Key Specifications

Pinout & Package

DO-214AC (SMA) package with two terminals: cathode band omitted for bidirectional configuration; terminals are symmetric and non-polarized. Moisture sensitivity level is Level 1 (no dry pack required); RoHS-compliant matte-tin plating meets MIL-STD-750 Method 2026 solderability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ8.5CA and SMBJ8.5CA, the SMAJ8.5CE3/TR13 delivers RoHS-compliant matte-tin termination, tighter 15.9 V clamping, and optimized DO-214AC footprint - making it preferred for modern high-density, lead-free production targeting IEC61000-4-5 Class 4 and ESD immunity.

Availability

SMAJ8.5CE3/TR13 is available at Aetrix Electronics and suitable for industrial PLC analog inputs, automotive body control modules, and DC power distribution boards requiring stable component supply, full traceability, and long-term lifecycle support.

Supply support for SMAJ8.5CE3/TR13 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

Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The SMAJ series was engineered for robust, surface-mount transient suppression in harsh environments - emphasizing low clamping voltage, high surge endurance, and extended temperature operation without derating.

FAQ

What does the "CE3/TR13" suffix mean in SMAJ8.5CE3/TR13?

The "C" indicates bidirectional configuration, "E3" denotes RoHS-compliant matte-tin plating, and "TR13" specifies tape-and-reel packaging with 2500 units per 13-inch reel per EIA-481-1-A standard. This exact combination ensures lead-free assembly compatibility, consistent orientation for automated placement, and verified moisture sensitivity Level 1 handling - all confirmed for SMAJ8.5CE3/TR13 in Microsemi's MSC0270A datasheet.

Is SMAJ8.5CE3/TR13 unidirectional or bidirectional?

SMAJ8.5CE3/TR13 is bidirectional, as confirmed by the "C" suffix in its part number and absence of cathode band marking. Its symmetrical avalanche structure provides identical clamping behavior for positive and negative transients - essential for protecting AC-coupled interfaces, differential buses, or floating grounds where polarity cannot be assumed. This is explicitly defined in the Microsemi SMAJ5.0–170CA datasheet.

What is the maximum clamping voltage of SMAJ8.5CE3/TR13 and under what test condition?

The maximum clamping voltage of SMAJ8.5CE3/TR13 is 15.9 V, measured at a peak pulse current (I_PP) of 31.4 A using the standardized 10/1000 µs double-exponential waveform per IEC61000-4-5. This value represents the highest voltage imposed on protected circuitry during worst-case surge events - a critical parameter for ensuring downstream ICs remain within absolute maximum ratings.

Does SMAJ8.5CE3/TR13 meet IEC61000-4-5 for lightning surge protection?

Yes, SMAJ8.5CE3/TR13 is certified for IEC61000-4-5 secondary lightning surge protection with 42 Ω source impedance (Class 4) and 12 Ω source impedance (Class 2), as documented in the Microsemi MSC0270A datasheet. Its 500 W peak pulse power rating and 31.4 A I_PP capacity directly satisfy Class 4 requirements - enabling use in industrial equipment and building automation systems requiring certified surge immunity.

What is the thermal resistance and power derating behavior of SMAJ8.5CE3/TR13?

SMAJ8.5CE3/TR13 has a junction-to-lead thermal resistance of 15 °C/W and junction-to-ambient resistance of 80 °C/W on FR4 with 1 oz copper and recommended footprint. Its steady-state power dissipation is 5 W at 75 °C lead temperature or 1.56 W at 25 °C ambient - meaning sustained power must be strictly limited outside transient conditions. Derating follows the curve in Figure 3 of MSC0270A, with full 500 W only valid at T_L ≤ 25 °C.