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Microchip Technology MPLAD18KP78A
- Part No.:
- MPLAD18KP78A
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- Nonstandard SMD
- Datasheet:
-
MPLAD18KP78A.pdf
- Description:
- TVS DIODE 78VWM 126VC PLAD
- Quantity:
- Payment:
- Shipping:
Inventory:9,549
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Product details
Overview
MPLAD18KP78A 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 ≤126 V under 100 A peak impulse current, and features a 78 V reverse standoff voltage (VWM) with 86.7–95.8 V breakdown range. It is widely deployed in aircraft lightning protection per RTCA DO-160 Section 22 and secondary surge suppression per IEC 61000-4-5.
For engineers reviewing the MPLAD18KP78A datasheet, MPLAD18KP78A pinout, MPLAD18KP78A application, or MPLAD18KP78A equivalent, key selection criteria include its 0.7 °C/W junction-to-case thermal resistance, metal-base cathode polarity, RoHS-compliant e3 plating, and validated performance under multi-stroke lightning waveforms and pin-injection transients (DO-160F Waveform 4 Level 4).
Technical Context
The MPLAD18KP78A employs a silicon avalanche diode structure optimized for low clamping ratio and minimal thermal resistance. Its metal-base package enables direct heatsinking, supporting sustained energy dissipation under repetitive surges at ≤0.05% duty factor. The device meets AEC-Q101 stress testing requirements and is rated for -55°C to +150°C operation.
It is characterized for IEC 61000-4-2 ESD (±30 kV contact), IEC 61000-4-4 EFT (40 A), and IEC 61000-4-5 surge (42 Ω, 12 Ω, and 2 Ω source impedances). Pin injection immunity per RTCA/DO-160F Waveform 4 (6.4/69 μs) is certified to Level 4 up to 78 V standoff, enabling use in avionics signal/power line protection without external heat sinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power (10/1000 μs) | 18,000 W - sustains full-rated lightning surge energy without failure |
| Reverse Standoff Voltage (VWM) | 78 V - maximum continuous DC or RMS operating voltage before conduction |
| Breakdown Voltage (V(BR)) | 86.7–95.8 V @ I(BR) - defines reliable avalanche initiation threshold |
| Max Clamping Voltage (VC @ IPP) | 126 V @ 100 A - limits protected circuit voltage during worst-case surge |
| Junction-to-Case Thermal Resistance | 0.7 °C/W - enables efficient heat transfer to PCB copper or heatsink |
| Standby Current (ID @ VWM) | 10 μA max - ensures negligible leakage in standby power rails |
| Clamping Response Time | <100 ps - sub-nanosecond turn-on for fast-rising transients |
Pinout & Package
Package: Surface-mount PLAD (Plastic Leaded Anode Down) with metal base acting as cathode terminal. Void-free UL94V-0 epoxy body; tin-lead or RoHS-compliant matte-tin plating; polarity marked by cathode on metal bottom surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Metal Base (Bottom) | Cathode | Primary heat path and high-current return node; must be soldered to large copper pour or heatsink |
| Top Lead (Anode) | Anode | Signal/power line input terminal; connects to line requiring protection |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SMT construction | Enables placement on dense PCBs without height clearance issues (max height 0.210″ / 5.33 mm) |
| 18 kW surge rating | Meets RTCA DO-160 Section 22 multi-stroke lightning test without degradation |
| 0.7 °C/W RθJC | Allows >70 W steady-state power handling when mounted on 10 cm² 2-oz copper |
| Moisture Sensitivity Level 1 | Eliminates dry-pack requirement and floor-life constraints per J-STD-020B |
| AEC-Q101 qualified | Validated for automotive under-hood environments including temperature cycling and humidity exposure |
Applications
| Aircraft Avionics Power Protection | Automotive Load Dump Suppression |
|---|---|
Use Scenario: Protecting 28 V DC distribution buses in commercial aircraft against DO-160F Section 22 lightning-induced surges. IC Role / Device Role / Timing Role: Primary transient clamp on main power feeders, placed upstream of DC-DC converters and flight control modules. Use Value: Withstands ≥1000A peak impulses at 126 V clamping, preventing latch-up or burnout in downstream regulators rated for <130 V absolute max. | Use Scenario: Safeguarding engine control units (ECUs) during alternator load dump events in 24 V commercial vehicles. IC Role / Device Role / Timing Role: High-power TVS placed across battery input terminals to clamp 120 V transients within 100 ns. Use Value: 18 kW rating absorbs full ISO 7637-2 Pulse 5a energy without derating, eliminating need for series impedance or staged protection. |
| Industrial Motor Drive DC Bus | Railway Signaling Interface |
Use Scenario: Protecting 75–80 V DC bus inputs in variable-frequency drives subject to IEC 61000-4-5 surge coupling. IC Role / Device Role / Timing Role: Secondary surge protector downstream of AC/DC front-end, absorbing residual transients from long cable runs. Use Value: 78 V VWM matches nominal bus voltage; 126 V VC ensures gate drivers and microcontrollers remain within safe operating area. | Use Scenario: Shielding 75 V signaling lines in European railway interlocking systems compliant with EN 50121-4 surge immunity. IC Role / Device Role / Timing Role: Line-side TVS on trackside communication interfaces exposed to induced lightning currents. Use Value: Validated for 42 Ω source impedance Class 4 surges (4 kV), providing margin over EN 50121-4 requirement of 2 kV. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78A | 600 W rating, SMB package, RθJA = 40 °C/W, no metal base | Limited to single-stroke surges; unsuitable for DO-160 multi-stroke or automotive load dump | Select only for low-energy board-level ESD where space and cost constrain use of 18 kW devices |
| SMCJ78A | 1500 W rating, SMC package, RθJA = 17 °C/W, plastic body only | Cannot meet 18 kW PPP or 0.7 °C/W thermal performance; lacks DO-160 certification | Acceptable for industrial IEC 61000-4-5 Class 3 where peak current ≤100 A and repetition is infrequent |
Compared with SMBJ78A and SMCJ78A, the MPLAD18KP78A provides 30× higher peak power handling, 20× lower thermal resistance, and formal qualification for aviation lightning standards-making it irreplaceable in mission-critical high-energy surge environments where reliability under repeated stress is mandatory.
Availability
MPLAD18KP78A is available at Aetrix Electronics and suitable for aircraft avionics, automotive power electronics, industrial motor drives, and railway signaling systems requiring stable component supply across extended production lifecycles.
Supply support for MPLAD18KP78A 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) designs high-reliability analog, mixed-signal, and power semiconductors for aerospace, defense, and industrial markets.
The MPLAD18KP78A belongs to Microsemi's high-power PLAD TVS family, engineered specifically for multi-stroke lightning protection and automotive load dump compliance in safety-critical platforms.
FAQ
What is the clamping voltage of the MPLAD18KP78A at its rated peak pulse current?
The MPLAD18KP78A has a maximum clamping voltage (VC) of 126 V when subjected to a 100 A peak pulse current (IPP) under the standard 10/1000 μs waveform. This value is measured per Figure 3 in the RF01215 datasheet and ensures protected circuits remain below critical voltage thresholds during surge events. The MPLAD18KP78A maintains this clamping performance across its full operating temperature range (-55°C to +150°C) with minimal derating.
Is the MPLAD18KP78A suitable for RTCA DO-160 Section 22 lightning testing?
Yes, the MPLAD18KP78A is explicitly validated for RTCA DO-160 Section 22 multi-stroke lightning testing. Its 18,000 W peak pulse power rating, sub-100 ps response time, and metal-base thermal design enable it to withstand repeated 10/1000 μs surges without degradation. The MPLAD18KP78A is listed in the DO-160F Waveform 4 Level 4 certification table for 78 V standoff devices, confirming its qualification for aircraft avionics power line protection.
How is polarity identified on the MPLAD18KP78A package?
The MPLAD18KP78A is a unidirectional TVS with cathode polarity assigned to the metal base (bottom surface) of the package. The top lead is the anode. This configuration is clearly stated in the "PLAD" nomenclature note: "The cathode is the metal base under the body of this device." Polarity marking is reinforced by functional layout-cathode must be connected to system ground or lowest potential reference for proper clamping operation.
Does the MPLAD18KP78A require dry pack or moisture-sensitive handling?
No, the MPLAD18KP78A has a Moisture Sensitivity Level (MSL) of 1 per IPC/JEDEC J-STD-020B, meaning it does not require dry pack packaging or floor-life controls. This eliminates baking requirements and simplifies SMT assembly logistics. The device's void-free UL94V-0 epoxy encapsulation and robust plating ensure long-term stability in humid environments without preconditioning.
What is the thermal resistance from junction to ambient for the MPLAD18KP78A?
The MPLAD18KP78A has a junction-to-ambient thermal resistance (RθJA) of 50 °C/W when mounted on an FR4 PCB with the recommended pad layout. However, its junction-to-case resistance (RθJC) is only 0.7 °C/W-indicating that effective heatsinking via the metal base dramatically improves thermal performance. For high-reliability applications, designers should connect the cathode base to ≥10 cm² of 2-oz copper to achieve near-RθJC-limited cooling, avoiding thermal runaway during repetitive surges.
MPLAD18KP78A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- Nonstandard SMD
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 143A
- Power - Peak Pulse:
- 18000W (18kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Military
- Qualification:
- MIL-PRF-19500
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PLAD
MPLAD18KP78A FAQ
1.How can I place an order for MPLAD18KP78A through Aetrix?
Please submit a Request for Quotation (RFQ) for MPLAD18KP78A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MPLAD18KP78A reliable?
The price and inventory of MPLAD18KP78A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPLAD18KP78A is usually 5 days.
3.What payment methods are accepted for MPLAD18KP78A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPLAD18KP78A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MPLAD18KP78A?
MPLAD18KP78A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MPLAD18KP78A order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MPLAD18KP78A?
For technical support, including MPLAD18KP78A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPLAD18KP78A requirements.
6.How does Aetrix verify that MPLAD18KP78A is sourced from the original manufacturer or authorized distributors?
All MPLAD18KP78A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MPLAD18KP78A meets industry standards.
7.What is the process for return or replacement of MPLAD18KP78A?
All MPLAD18KP78A units undergo pre-shipment inspection (PSI). If there is an issue with MPLAD18KP78A, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MPLAD18KP78A part is unused and in its original packaging.
Return procedure for MPLAD18KP78A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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