Microchip Technology MAPLAD18KP85CA

Overview

MAPLAD18KP85CA 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 ≤137 V under 100 A peak impulse current, and features 78 V reverse standoff voltage (VWM) with ±5% breakdown tolerance (94.4–104.0 V). It is qualified to AEC-Q101 and meets RTCA DO-160F Waveform 4 Level 4 and IEC 61000-4-5 Class 1–5 secondary lightning protection requirements.

For engineers reviewing the MAPLAD18KP85CA datasheet, MAPLAD18KP85CA pinout, MAPLAD18KP85CA application, or MAPLAD18KP85CA equivalent, this device serves as a high-reliability, low-profile TVS for multi-stroke lightning protection, load dump suppression, and ESD/EFT hardening in avionics power rails and vehicle ECUs - where thermal resistance (RθJC = 0.7 °C/W), RoHS-compliant matte-tin terminations, and MIL-PRF-19500 upscreening options are critical selection criteria.

Technical Context

The MAPLAD18KP85CA employs an avalanche diode structure optimized for fast response (<5 ns clamping time) and low dynamic impedance to limit transient overvoltage across protected circuits. Its metal-base package enables direct thermal coupling to heatsinks, supporting sustained operation at junction temperatures from –55 °C to +150 °C with derated PPP above 100 °C.

It operates bidirectionally with symmetrical clamping behavior, meeting IEC 61000-4-2 (±30 kV contact), IEC 61000-4-4 (±4 kV), and RTCA DO-160F pin-injection standards. Standby leakage (ID ≤10 μA @ 78 V) ensures minimal impact on upstream bias networks in always-on systems.

Key Specifications

Pinout & Package

MAPLAD18KP85CA uses a surface-mount PLAD package with two terminals: cathode and anode symmetrically arranged on opposite ends of the metal base. The metal base serves as the common thermal path and electrical connection point; polarity is non-directional due to bidirectional construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ78CA and SMCJ78CA, MAPLAD18KP85CA provides 30× higher peak power handling, 2× lower thermal resistance, and documented DO-160F Waveform 4 Level 4 and IEC 61000-4-5 Class 5 compliance - making it the only option for certified airborne power entry protection and high-reliability load dump mitigation.

Availability

MAPLAD18KP85CA is available at Aetrix Electronics and suitable for aircraft power distribution units, automotive engine control modules, and railway signaling interfaces requiring stable component supply across extended product lifecycles and rigorous environmental qualification.

Supply support for MAPLAD18KP85CA 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, RF, and timing solutions for aerospace, defense, and industrial markets.

The MAPLAD18KP85CA belongs to Microsemi's PLAD-series high-power TVS family, engineered specifically for multi-stroke lightning protection and automotive load dump suppression in safety-critical platforms where thermal robustness and regulatory certification are mandatory.

FAQ

What is the clamping voltage of MAPLAD18KP85CA at its rated peak pulse current?

The MAPLAD18KP85CA has a maximum clamping voltage (VC) of 137 V when subjected to a 100 A peak impulse current (IPP) under the standard 10/1000 μs waveform. This value is measured across the device terminals and represents the upper voltage limit imposed on protected circuitry during worst-case transient events, ensuring downstream components remain within safe operating margins.

Is MAPLAD18KP85CA compliant with automotive reliability standards?

Yes, MAPLAD18KP85CA is qualified to AEC-Q101 for stress testing including temperature cycling, humidity, and mechanical shock. It is explicitly rated for automotive load dump protection and supports operation across –55 °C to +150 °C junction temperature range - meeting requirements for engine bay and powertrain control module deployments.

Does MAPLAD18KP85CA require a heatsink for full 18 kW pulse handling?

No discrete heatsink is required for single-pulse 18 kW events, as the device's 0.7 °C/W junction-to-case thermal resistance allows effective heat dissipation into a properly designed PCB copper pour. However, for repetitive surges (>0.05% duty cycle), thermal derating per Figure 3 in RF01215 Rev B must be applied to avoid exceeding 150 °C junction temperature.

How does the CA suffix in MAPLAD18KP85CA affect its functionality?

The "CA" suffix denotes bidirectional construction, meaning MAPLAD18KP85CA provides symmetrical clamping for both positive and negative transients without polarity sensitivity. Unlike unidirectional variants (e.g., MAPLAD18KP85A), it can protect AC-coupled lines, differential buses, or floating grounds without requiring orientation-aware layout.

Can MAPLAD18KP85CA be used for IEC 61000-4-5 compliance testing?

Yes, MAPLAD18KP85CA is validated for IEC 61000-4-5 secondary lightning protection across Classes 1–5 with 42 Ω source impedance, and Classes 1–4 with 12 Ω impedance. Its 78 V VWM and 137 V VC provide sufficient margin to pass 4 kV tests on 24–48 V systems while maintaining low leakage (<10 μA) during normal operation.