Microchip Technology MAPLAD18KP85AE3

Overview

MAPLAD18KP85AE3 from Microsemi is a unidirectional surface-mount transient voltage suppressor (TVS) designed for high-energy surge protection in aerospace and automotive systems. It delivers 18,000 W peak pulse power at 10/1000 μs, features a 85 V reverse standoff voltage (VWM), clamps to ≤137 V at 1000 A IPP, and exhibits <100 ps response time. It is qualified to AEC-Q101 and meets RTCA DO-160F Waveform 4 Level 4 and IEC 61000-4-5 Class 1–5 lightning standards.

For engineers reviewing the MAPLAD18KP85AE3 datasheet, MAPLAD18KP85AE3 pinout, MAPLAD18KP85AE3 application, or MAPLAD18KP85AE3 equivalent, key selection criteria include its 85 V VWM rating, 137 V max clamping voltage at 1000 A, 0.7 °C/W junction-to-case thermal resistance, RoHS-compliant e3 plating, and qualification for aircraft secondary lightning protection per DO-160F Section 22.

Technical Context

This TVS diode employs an avalanche breakdown mechanism optimized for multi-stroke lightning transients, with a metal-base cathode configuration enabling low-inductance, high-current conduction paths. Its thermoset epoxy package achieves UL94V-0 flammability rating and supports direct mounting to heatsinks via the metal backside for thermal management.

The device operates across –55°C to +150°C junction temperature range and maintains stable clamping performance under repetitive surges at ≤0.05% duty factor. Its 5.0 mV/°C temperature coefficient of breakdown voltage ensures predictable V(BR) drift over temperature, critical for precision protection in avionics power buses.

Key Specifications

Pinout & Package

MAPLAD18KP85AE3 uses a surface-mount PLAD package with two terminals: anode (top-side metallization) and cathode (exposed metal base). The cathode serves as the primary thermal path and must be soldered directly to a copper pour or heatsink for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ85A and SMCJ85A, MAPLAD18KP85AE3 delivers 30× higher peak pulse power, 10× lower clamping voltage at rated current, and certified compliance with aviation lightning standards-making it the sole option for DO-160F Section 22–qualified designs requiring 18 kW surge handling.

Availability

MAPLAD18KP85AE3 is available at Aetrix Electronics and suitable for avionics power distribution, automotive ECU protection, and industrial motor drive DC link applications requiring stable component supply across extended product lifecycles.

Supply support for MAPLAD18KP85AE3 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for aerospace, defense, and industrial markets.

The MAPLAD series was developed specifically for multi-stroke lightning protection in certified aircraft systems, emphasizing ultra-low thermal resistance, DO-160F compliance, and full lot traceability for safety-critical deployments.

FAQ

What is the maximum clamping voltage of MAPLAD18KP85AE3 at its rated peak pulse current?

The MAPLAD18KP85AE3 has a maximum clamping voltage (VC) of 137 V at 1000 A peak pulse current (IPP) under 10/1000 μs waveform conditions. This value is guaranteed per the manufacturer's electrical characteristics table and ensures protected circuitry remains below critical overvoltage thresholds during lightning transients. The clamping performance is validated across the full operating temperature range and forms the basis for system-level DO-160F compliance testing.

Is MAPLAD18KP85AE3 qualified for use in automotive applications?

Yes, MAPLAD18KP85AE3 is AEC-Q101 qualified for automotive applications, having passed stress tests including temperature cycling, highly accelerated stress testing (HAST), and mechanical shock. Its 85 V VWM rating and 137 V clamping voltage make it suitable for 24 V commercial vehicle load dump protection. However, its primary design focus remains aviation-grade lightning immunity per RTCA DO-160F Section 22, which exceeds typical automotive surge requirements.

How does the metal-base cathode configuration of MAPLAD18KP85AE3 impact thermal management?

The metal-base cathode of MAPLAD18KP85AE3 serves as the primary thermal conduction path, achieving a junction-to-case thermal resistance (RθJC) of just 0.7 °C/W. This requires direct soldering of the cathode to a large copper pour or external heatsink. Failure to implement proper thermal mounting results in rapid junction temperature rise during surge events, potentially exceeding the 150 °C maximum rating and causing permanent degradation of the MAPLAD18KP85AE3.

Does MAPLAD18KP85AE3 meet RoHS requirements, and what does the "E3" suffix indicate?

Yes, MAPLAD18KP85AE3 is RoHS compliant, as confirmed by the "E3" suffix in its part number. This denotes annealed matte-tin plating per J-STD-020B Level 1 moisture sensitivity, eliminating the need for dry-pack packaging and enabling standard reflow soldering processes. The e3 marking is verified in the manufacturer's nomenclature guide and aligns with Microsemi's RoHS-compliant product portfolio documentation.

Can MAPLAD18KP85AE3 be used for bidirectional transient suppression?

No, MAPLAD18KP85AE3 is a unidirectional TVS diode, indicated by the "A" (not "CA") suffix. It conducts only during positive transients relative to its cathode. For bidirectional protection, the manufacturer specifies the MAPLAD18KP85CA variant. Using MAPLAD18KP85AE3 in bidirectional configurations risks catastrophic failure during negative-going surges, as it lacks reverse breakdown capability-this limitation is explicitly defined in the part nomenclature and electrical characteristics tables.