Microchip Technology MAPLAD18KP43A

Overview

MAPLAD18KP43A 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, clamps at ≤69.4 V under 260 A peak impulse current, and features a 43 V reverse standoff voltage (VWM) with 47.8–52.8 V breakdown range. It is qualified to AEC-Q101 and meets RTCA DO-160F Waveform 4 Level 4 for pin injection protection.

For engineers reviewing the MAPLAD18KP43A datasheet, MAPLAD18KP43A pinout, MAPLAD18KP43A application, or MAPLAD18KP43A equivalent, this device serves as a high-reliability secondary lightning protector in avionics power rails, engine control units, and DC bus interfaces where thermal resistance minimization and multi-stroke surge endurance are critical.

Technical Context

The MAPLAD18KP43A employs an avalanche diode structure optimized for low clamping ratio and fast response (<100 ps), enabling effective suppression of lightning-induced transients per IEC 61000-4-5 (42 Ω, 12 Ω, and 2 Ω source impedances) and ESD/EFT per IEC 61000-4-2/4-4. Its metal-base cathode construction provides direct thermal path to PCB copper, achieving 0.7 °C/W junction-to-case thermal resistance.

It operates across –55°C to +150°C junction temperature range, supports steady-state dissipation up to 2.5 W at 25°C ambient, and maintains <10 μA standby current at rated VWM - critical for low-power monitoring circuits in always-on vehicle subsystems.

Key Specifications

Pinout & Package

MAPLAD18KP43A uses a surface-mount PLAD package with metal base cathode configuration. The device has two terminals: anode (top-side marked side) and cathode (unmarked metal bottom surface). Thermal performance relies on soldering the cathode base directly to a large copper pad per recommended layout (Ref. RF01215).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ43A and SMCJ43A, the MAPLAD18KP43A delivers 30× and 12× higher peak pulse power respectively, supports certified multi-stroke lightning endurance, and enables compact placement on high-density avionics PCBs via its metal-base thermal design - making it irreplaceable for DO-160-certified systems.

Availability

MAPLAD18KP43A is available at Aetrix Electronics and suitable for avionics power distribution, automotive engine control units, industrial motor drives, and railway signaling power supplies requiring stable component supply across long production lifecycles.

Supply support for MAPLAD18KP43A 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 solutions for aerospace, defense, and industrial markets.

The MAPLAD18KP43A belongs to Microsemi's high-power PLAD TVS family, engineered specifically for DO-160-compliant aircraft systems and AEC-Q101-qualified automotive power electronics demanding multi-kilowatt surge resilience.

FAQ

What is the clamping voltage of MAPLAD18KP43A at its rated peak pulse current?

The MAPLAD18KP43A exhibits a maximum clamping voltage (VC) of 69.4 V at its rated peak pulse current (IPP) of 260 A under 10/1000 μs waveform conditions. This value is measured per Figure 3 in RF01215 Rev B and defines the upper voltage limit imposed on protected circuitry during worst-case surge events. The low clamping ratio (VC/VWM ≈ 1.61) ensures compatibility with 75 V-rated downstream components.

Is MAPLAD18KP43A qualified for automotive applications?

Yes, MAPLAD18KP43A is fully qualified to AEC-Q101 for stress testing including HTSL, TCT, and surge. Its 43 V VWM and 69.4 V clamping align with 36 V automotive systems experiencing load dump, and its –55°C to +150°C operating range covers under-hood environments. It is explicitly listed in RF01215 for automotive load dump protection alongside lightning standards.

Does MAPLAD18KP43A require special PCB layout considerations?

Yes - the cathode is the metal base underside, requiring direct soldering to a minimum 12.3 mm × 10.5 mm copper pad per RF01215 pad layout. This thermal pad must be connected to internal ground planes via ≥6 thermal vias (0.3 mm diameter) to maintain RθJA ≤50 °C/W. Failure to implement this results in junction overheating and premature failure during repetitive surges.

What is the moisture sensitivity level (MSL) of MAPLAD18KP43A?

MAPLAD18KP43A is rated MSL Level 1 per IPC/JEDEC J-STD-020B, meaning it has unlimited floor life and requires no dry pack or baking prior to reflow soldering. This eliminates moisture-related defects such as popcorn cracking and reduces manufacturing overhead - a key advantage over MSL 3+ TVS devices in high-volume SMT lines.

Can MAPLAD18KP43A be used for bidirectional surge protection?

No - MAPLAD18KP43A is unidirectional (denoted by "A" suffix). For bidirectional protection at 43 V standoff, the correct variant is MAPLAD18KP43CA. Using MAPLAD18KP43A in AC-coupled or floating-ground applications risks forward conduction and permanent damage during negative transients, as confirmed by polarity marking and cathode-base construction in RF01215.