Microchip Technology MAPLAD18KP70A

Overview

MAPLAD18KP70A from Microsemi is a unidirectional surface-mount transient voltage suppressor (TVS) designed for high-energy surge protection in aerospace and automotive power systems. It delivers 18,000 W peak pulse power at 10/1000 μs, clamps at ≤113 V under 100 A peak impulse current, and features a 70 V reverse standoff voltage (VWM) with 77.8–86.0 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 MAPLAD18KP70A datasheet, MAPLAD18KP70A pinout, MAPLAD18KP70A application, or MAPLAD18KP70A equivalent, this device is selected for lightning robustness in avionics power rails, load-dump immunity in 24 V vehicle ECUs, and secondary IEC 61000-4-5 Class 1–5 protection with 42 Ω source impedance - requiring precise VWM margining, thermal derating awareness, and cathode-side PCB layout planning.

Technical Context

The MAPLAD18KP70A employs an avalanche diode structure optimized for low clamping ratio (VC/V(BR) ≈ 1.45 max) and sub-100 ps response time. Its metal-base package enables direct thermal coupling to heatsinks, achieving 0.7 °C/W junction-to-case resistance and supporting sustained operation up to +150 °C junction temperature.

It is rated for multi-stroke lightning compliance per RTCA DO-160 Section 22 and provides ESD immunity per IEC 61000-4-2 (±30 kV contact), EFT per IEC 61000-4-4 (±4 kV), and secondary lightning per IEC 61000-4-5 across 2 Ω, 12 Ω, and 42 Ω source impedances - with defined class coverage (e.g., Class 1–5 at 42 Ω).

Key Specifications

Pinout & Package

MAPLAD18KP70A uses a surface-mount PLAD package with exposed metal base acting as the cathode terminal. The package measures 12.32 × 10.54 × 5.33 mm (L × W × H) and features tin-lead or RoHS-compliant matte-tin plating on terminals. Mounting requires thermal pad layout per datasheet Figure 7 (recommended copper area ≥ 2500 mm² for RθJA = 50 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ70A and SMCJ70A, the MAPLAD18KP70A delivers 12× higher peak pulse power, 0.7 °C/W junction-to-case thermal resistance enabling direct heatsink mounting, and formal qualification to RTCA DO-160F and AEC-Q101 - making it uniquely suitable for certified aerospace and automotive safety-critical power protection.

Availability

MAPLAD18KP70A is available at Aetrix Electronics and suitable for avionics power conditioning, commercial vehicle ECU protection, and industrial motor drive DC bus safeguarding requiring stable component supply across extended production lifecycles.

Supply support for MAPLAD18KP70A 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, RF, and timing solutions for aerospace, defense, and industrial markets.

The PLAD family, including MAPLAD18KP70A, was engineered specifically for multi-stroke lightning resilience and high-temperature operation in mission-critical power interfaces - targeting DO-160, AEC-Q101, and IEC 61000-4-5 compliance out-of-the-box.

FAQ

What is the clamping voltage of MAPLAD18KP70A at its rated peak pulse current?

The MAPLAD18KP70A has a maximum clamping voltage (VC) of 113 V at 100 A peak pulse current (IPP) 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 surge events. The MAPLAD18KP70A maintains this clamping performance across its full operating temperature range when properly mounted with adequate thermal mass.

Is MAPLAD18KP70A suitable for bidirectional signal line protection?

No, MAPLAD18KP70A is unidirectional and intended for DC power rail protection where polarity is fixed. For bidirectional applications such as AC lines or differential data buses, the MAPLAD18KP70CA variant must be used instead. The "A" suffix explicitly denotes unidirectional construction, and the cathode is located on the metal base - incorrect orientation will prevent proper clamping.

Does MAPLAD18KP70A require moisture sensitivity handling prior to reflow?

No, MAPLAD18KP70A is rated Moisture Sensitivity Level 1 per IPC/JEDEC J-STD-020B, meaning it can be stored indefinitely at ambient conditions and placed directly into reflow without baking or dry packing. This eliminates process steps and reduces risk of popcorn cracking during assembly - a key advantage over higher-MSL TVS devices.

How does the thermal design of MAPLAD18KP70A differ from standard SMC/SMB TVS diodes?

Unlike standard SMC/SMB packages, MAPLAD18KP70A uses a metal-base PLAD package with 0.7 °C/W junction-to-case thermal resistance, enabling direct thermal coupling to heatsinks or large PCB copper areas. Standard SMC devices typically exhibit >10 °C/W RθJC. This allows MAPLAD18KP70A to sustain repeated surges without thermal accumulation - critical for DO-160 multi-stroke compliance - whereas conventional packages would thermally saturate.

Can MAPLAD18KP70A replace older MOV-based protection in avionics designs?

Yes, MAPLAD18KP70A is frequently used to replace MOVs in avionics due to its precise VWM tolerance, sub-100 ps response time, no degradation after repeated surges, and DO-160F certification. MOVs exhibit parameter drift and wear-out; MAPLAD18KP70A maintains consistent clamping performance over lifetime. However, layout must accommodate its cathode-down mounting and larger thermal pad - direct footprint replacement is not possible without redesign.