Microchip Technology MAPLAD18KP40CA

Overview

MAPLAD18KP40CA from Microsemi is a bidirectional 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 ≤64.5 V under 280 A peak impulse current, and features a 40 V reverse standoff voltage (VWM) with ±5% breakdown tolerance (44.4–49.1 V). It is qualified to AEC-Q101 and meets RTCA DO-160F Level 4 pin injection for Waveform 4.

For engineers reviewing the MAPLAD18KP40CA datasheet, MAPLAD18KP40CA pinout, MAPLAD18KP40CA application, or MAPLAD18KP40CA equivalent, key selection criteria include its bidirectional polarity, 0.7 °C/W junction-to-case thermal resistance, IEC 61000-4-5 Class 1–5 secondary lightning protection capability, and RoHS-compliant e3 plating - all critical for high-reliability avionics and vehicle ECU designs.

Technical Context

The MAPLAD18KP40CA employs an avalanche diode structure optimized for multi-stroke lightning transients per RTCA DO-160 Section 22. Its low R_θJC (0.7 °C/W) enables effective heat transfer to the PCB copper pad or heatsink, supporting repetitive surge duty cycles ≤0.05%. The device operates across –55 °C to +150 °C junction temperature range with <100 ps response time from 0 V to V(BR) min.

It is rated for 42 Ω, 12 Ω, and 2 Ω source impedances per IEC 61000-4-5, covering Class 1–5 protection levels depending on impedance configuration. Bidirectional construction ensures symmetrical clamping for AC-coupled or floating signal lines, while the metal-base cathode design provides low-inductance current path and stable thermal performance under sustained surge stress.

Key Specifications

Pinout & Package

MAPLAD18KP40CA uses a surface-mount PLAD package with metal base cathode terminal and top-side anode pad. The package is void-free thermosetting epoxy (UL94V-0), with matte-tin RoHS-compliant plating (e3) and body marking. Recommended pad layout per RF01215 Rev B includes 12.32–12.57 mm length (A1), 10.54–10.80 mm width (A2), and 5.08–5.33 mm terminal width (D).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAPLAD18KP40CA, SMBJ40CA and SMCJ40CA offer lower cost and smaller footprint but cannot meet 18 kW surge absorption, multi-stroke endurance, or aviation-grade certification - making them unsuitable replacements in safety-critical aerospace or high-power automotive systems.

Availability

MAPLAD18KP40CA is available at Aetrix Electronics and suitable for avionics interface protection, automotive powertrain ECU surge hardening, and industrial motor drive I/O shielding requiring stable component supply across long production lifecycles.

Supply support for MAPLAD18KP40CA 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 MAPLAD family was engineered specifically for multi-stroke lightning and load dump protection in certified avionics and automotive systems, emphasizing thermal robustness, AEC-Q101 qualification, and RTCA DO-160F compliance.

FAQ

What is the clamping voltage of MAPLAD18KP40CA at its rated peak pulse current?

The MAPLAD18KP40CA has a maximum clamping voltage (V_C) of 64.5 V when subjected to its rated peak pulse current of 280 A under 10/1000 μs waveform conditions. This value is measured per standard test methods defined in the RF01215 datasheet and ensures downstream circuitry remains within safe operating voltage limits during surge events. The MAPLAD18KP40CA maintains this clamping performance across its full operating temperature range.

Is MAPLAD18KP40CA qualified for automotive applications?

Yes, MAPLAD18KP40CA is fully qualified to AEC-Q101 for automotive use, including extended temperature operation from –55 °C to +150 °C and rigorous stress testing for humidity, thermal cycling, and mechanical shock. It is specifically intended for high-reliability automotive subsystems such as engine control units, transmission controllers, and ADAS domain controllers where load dump and EFT immunity are mandatory. The MAPLAD18KP40CA meets ISO 7637-2 Pulse 5a/b requirements when properly mounted.

Does MAPLAD18KP40CA require dry pack handling per J-STD-020?

No, MAPLAD18KP40CA is rated Moisture Sensitivity Level 1 (MSL-1) per IPC/JEDEC J-STD-020B, meaning it has no floor life limitation and does not require dry pack storage or baking prior to reflow soldering. This simplifies manufacturing logistics and eliminates moisture-related popcorning risks during SMT assembly. The MAPLAD18KP40CA's void-free epoxy encapsulation and e3 RoHS plating contribute to its MSL-1 classification.

How does the thermal performance of MAPLAD18KP40CA compare to standard SMB/SMC TVS diodes?

MAPLAD18KP40CA achieves a junction-to-case thermal resistance (R_θJC) of just 0.7 °C/W - over 10× lower than typical SMBJ (≈25 °C/W) or SMCJ (≈10 °C/W) devices - due to its metal-base construction and optimized internal die attach. This enables direct heat transfer to PCB copper or external heatsinks, sustaining repetitive 18 kW surges without thermal runaway. In contrast, standard SMB/SMC packages rely on less efficient plastic-body conduction, limiting their duty cycle capability. The MAPLAD18KP40CA's thermal advantage is essential for RTCA DO-160 multi-stroke compliance.

Can MAPLAD18KP40CA be used for bidirectional signal line protection?

Yes, the "CA" suffix in MAPLAD18KP40CA explicitly denotes bidirectional construction, enabling symmetrical clamping for AC-coupled, differential, or floating signal paths such as RS-485, CAN FD, or MIL-STD-1553B buses. Its matched forward/reverse breakdown characteristics ensure consistent protection regardless of transient polarity. Unlike unidirectional TVS diodes, the MAPLAD18KP40CA does not require external biasing or polarity-aware layout - simplifying design and improving robustness in bidirectional interfaces.