Microchip Technology MAPLAD18KP18A

Overview

MAPLAD18KP18A from Microsemi is a unidirectional surface-mount transient voltage suppressor (TVS) designed for high-energy surge protection in aerospace, automotive, and industrial power systems. It delivers 18,000 W peak pulse power at 10/1000 μs, clamps at ≤29.2 V under 617 A peak impulse current, and features 18 V reverse standoff voltage (VWM) with 20.0–22.1 V breakdown voltage (V(BR)). It is widely deployed in aircraft lightning protection per RTCA DO-160 Section 22.

For engineers reviewing the MAPLAD18KP18A datasheet, MAPLAD18KP18A pinout, MAPLAD18KP18A application, or MAPLAD18KP18A equivalent, key selection criteria include its 18 kW PPP rating, low 0.7 °C/W junction-to-case thermal resistance, RoHS-compliant e3 plating, IEC 61000-4-5 Class 4 secondary lightning compliance (42 Ω source), and RTCA DO-160F Waveform 4 Level 4 pin injection capability.

Technical Context

The MAPLAD18KP18A operates as a silicon avalanche diode-based unidirectional TVS, leveraging controlled avalanche breakdown to clamp transients before downstream circuitry sustains damage. Its metal-base cathode construction enables direct thermal coupling to heatsinks, supporting high-repetition-rate surge handling when mounted per recommended FR4 pad layout.

It meets AEC-Q101 stress testing requirements and supports MIL-PRF-19500 upscreening options (M/MA/MXL levels). Electrical behavior is defined by tight V(BR) tolerance (±5%), low standby current (≤10 μA @ 18 V), and temperature coefficient of 19 mV/°C - enabling predictable clamping across -55°C to +150°C operating range.

Key Specifications

Pinout & Package

MAPLAD18KP18A uses a surface-mount plastic package with metal base cathode configuration. The cathode is the exposed metal underside (thermal slug), while the anode is the top-side metallized terminal. Package dimensions: 12.32 × 10.54 × 3.68 mm (L × W × H), with recommended FR4 mounting pad per RF01215 Rev B.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ18A and SMCJ18A, the MAPLAD18KP18A delivers 30× and 12× higher peak pulse power respectively, with superior thermal performance enabling single-device solutions in aerospace and heavy-duty industrial systems where reliability under repetitive surges is non-negotiable.

Availability

MAPLAD18KP18A is available at Aetrix Electronics and suitable for aircraft avionics, automotive ECU power systems, and industrial programmable logic controller (PLC) inputs requiring stable component supply across extended product lifecycles.

Supply support for MAPLAD18KP18A 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 radiation-hardened components for aerospace, defense, and industrial markets.

The MAPLAD18KP18A belongs to Microsemi's PLAD high-power TVS family, engineered specifically for mission-critical surge protection where multi-stroke lightning resilience, AEC-Q101 qualification, and MIL-PRF-19500 upscreening capability are mandatory.

FAQ

What is the clamping voltage of MAPLAD18KP18A at its rated peak pulse current?

The MAPLAD18KP18A has a maximum clamping voltage (VC) of 29.2 V at 617 A peak pulse current (IPP) under 10/1000 μs waveform conditions. This value is guaranteed across temperature and production lots, ensuring protected circuits remain below critical voltage thresholds during surge events. The MAPLAD18KP18A achieves this with minimal voltage overshoot due to its low-inductance metal-base construction.

Is MAPLAD18KP18A suitable for bidirectional surge protection?

No - MAPLAD18KP18A is a unidirectional TVS diode, intended for DC or polarity-defined AC applications. For bidirectional protection, the MAPLAD18KP18CA variant must be used. The "A" suffix explicitly denotes unidirectional polarity, and using MAPLAD18KP18A in AC-coupled or floating systems risks catastrophic failure during reverse-biased transients.

Does MAPLAD18KP18A require a heatsink for standard operation?

MAPLAD18KP18A does not require an external heatsink for single-pulse events, but thermal management is essential for repetitive surges. Its 0.7 °C/W RθJC demands direct soldering of the metal base to ≥250 mm² of 2 oz copper on FR4, per RF01215 recommended pad layout. Without adequate copper area, junction temperature rise exceeds safe limits even at 0.05% duty cycle - a condition explicitly validated in the MAPLAD18KP18A datasheet.

What certifications does MAPLAD18KP18A meet for aerospace applications?

MAPLAD18KP18A is qualified to AEC-Q101 and supports MIL-PRF-19500 upscreening (M/MA/MXL levels). It is validated for RTCA DO-160F Section 22 lightning-induced transient testing (Waveform 4 Level 4 and Waveform 5A Level 4), and meets IEC 61000-4-5 Class 4 secondary lightning protection with 42 Ω source impedance. These certifications are documented in Microsemi's RF01215 Rev B specification report for MAPLAD18KP18A.

Can MAPLAD18KP18A replace older 15 kW TVS devices in existing designs?

Yes - MAPLAD18KP18A is a direct upgrade path from legacy 15 kW TVS diodes such as the MPLAD15KP18A, offering 20% higher peak pulse power while maintaining identical footprint, pinout, and VWM/V(BR) specifications. Its improved thermal resistance (0.7 vs. 0.9 °C/W) also reduces junction temperature rise by ~30% under identical surge conditions, extending service life in high-reliability applications. No PCB changes are required for drop-in replacement of MAPLAD18KP18A.