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Microchip Technology MAPLAD18KP78AE3
- Part No.:
- MAPLAD18KP78AE3
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- Nonstandard SMD
- Datasheet:
-
MAPLAD18KP78AE3.pdf
- Description:
- TVS DIODE 78VWM 126VC PLAD
- Quantity:
- Payment:
- Shipping:
Inventory:9,970
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Product details
Overview
MAPLAD18KP78AE3 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 ≤126 V under 100 A peak impulse current, and features a 78 V reverse standoff voltage (VWM) with ±5% breakdown tolerance (86.7–95.8 V). It is qualified to AEC-Q101 and meets RTCA DO-160F Level 4 pin injection for Waveform 4.
For engineers reviewing the MAPLAD18KP78AE3 datasheet, MAPLAD18KP78AE3 pinout, MAPLAD18KP78AE3 application, or MAPLAD18KP78AE3 equivalent, this device is selected for secondary lightning protection per IEC 61000-4-5 (42 Ω source), load dump suppression in 24 V vehicle architectures, and ESD/EFT hardening per IEC 61000-4-2/4-4 - requiring verified clamping voltage, thermal resistance <0.7 °C/W, and RoHS-compliant matte-tin terminations.
Technical Context
This TVS uses silicon avalanche diode technology optimized for low clamping ratio and fast response (<100 ps rise time), enabling effective suppression of multi-stroke lightning transients per RTCA DO-160 Section 22. Its metal-base package provides direct thermal path to PCB copper, achieving RθJC = 0.7 °C/W and supporting sustained operation up to +150 °C junction temperature.
The device operates in unidirectional mode with cathode on the metal base (bottom side), requiring correct PCB pad layout per RF01215 Rev B. Standby leakage is tightly controlled (ID ≤10 μA @ 78 V), and it undergoes 3σ lot norm screening on ID to ensure reliability in safety-critical avionics and engine control modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power (10/1000 μs) | 18,000 W - sustains full-rated surge energy without degradation in aircraft lightning test cycles |
| Reverse Standoff Voltage (VWM) | 78 V - maximum continuous DC or peak AC voltage before conduction begins; matches 24 V system derated for transients |
| Clamping Voltage (VC @ IPP=100 A) | 126 V max - limits downstream voltage stress during surge, enabling robust interface protection for 100 V-rated ICs |
| Junction-to-Case Thermal Resistance | 0.7 °C/W - enables efficient heat transfer to heatsink or large copper pour, critical for repeated surge duty |
| Breakdown Voltage Range | 86.7–95.8 V @ I(BR) - ensures reliable turn-on margin above VWM while avoiding false triggering |
| Standby Leakage Current | ≤10 μA @ 78 V - minimizes quiescent power loss in always-on vehicle subsystems |
| RoHS Compliance | e3 marking - matte-tin plating compliant with EU Directive 2011/65/EU, no lead or hazardous substances |
Pinout & Package
MAPLAD18KP78AE3 uses a surface-mount PLAD package with two terminals: anode and cathode. The cathode is electrically connected to the exposed metal base (bottom side), requiring dedicated thermal pad connection to PCB ground plane or heatsink. Anode is accessible via top-side metallization.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Positive input terminal | Connected to protected line (e.g., battery feed); must be routed with low-inductance trace to minimize overshoot |
| Cathode (Metal Base) | Reference/return terminal | Direct thermal and electrical connection to PCB ground plane; requires ≥100 mm² copper area for optimal RθJA |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SMT construction | Height ≤0.210 in (5.33 mm) - fits constrained avionics enclosures and under-hood automotive ECUs |
| RTCA DO-160F Waveform 4 compliance | Level 4 certified (6.4/69 μs, 25 °C) - validated for pin-injection immunity in flight-critical sensors and controllers |
| IEC 61000-4-5 secondary lightning protection | Class 1–5 rated with 42 Ω source - meets airframe-level surge requirements without external impedance matching |
| AEC-Q101 qualification | Stress-tested per automotive electronics reliability standard - suitable for engine control, ADAS, and body electronics |
| MIL-PRF-19500 upscreening option | Available with M/MA/MXL reliability levels - supports military and space-grade procurement without redesign |
Applications
| Aerospace Avionics Power Bus | Automotive Engine Control Unit (ECU) |
|---|---|
Use Scenario: Protection of 28 V DC distribution bus against lightning-induced surges per RTCA DO-160 Section 22. IC Role / Device Role / Timing Role: Primary transient clamp on main power rail upstream of DC-DC converters and microcontrollers. Use Value: Limits bus voltage to ≤126 V during 18 kW transients, preventing latch-up or burnout in downstream PMICs and CAN transceivers. |
Use Scenario: Load dump suppression in 24 V gasoline/diesel engine management systems per ISO 7637-2 Pulse 5a. IC Role / Device Role / Timing Role: Unidirectional TVS placed across battery input to absorb 120 V/100 ms transients generated by alternator field collapse. Use Value: Clamps peak voltage below 130 V, safeguarding 5 V/3.3 V logic supplies and flash memory in engine control modules. |
| Industrial Motor Drive DC Link | Railway Signaling Interface |
Use Scenario: Surge protection on DC link capacitor banks in variable-frequency drives exposed to switching transients and induced RFI. IC Role / Device Role / Timing Role: Parallel-connected TVS across 80–100 V DC bus to shunt commutation spikes and EFT bursts. Use Value: Withstands repetitive 10/1000 μs surges at 0.05% duty cycle, maintaining clamping performance over 10⁵ events without drift. |
Use Scenario: Secondary protection for 72 V signaling lines in European railway ETCS Level 2 balise interfaces subject to IEC 61000-4-5 Class 4 surges. IC Role / Device Role / Timing Role: Bidirectional-capable variant used (MPLAD18KP78CA), but MAPLAD18KP78AE3 serves as unidirectional alternative where polarity is fixed. Use Value: Provides 126 V clamping at 100 A with <0.7 °C/W thermal resistance, ensuring stable operation in sealed trackside cabinets at +70 °C ambient. |
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 | Lower PPP rating (600 W), smaller SMB package, RθJC ≈ 35 °C/W | Not suitable for DO-160 Level 4 or IEC 61000-4-5 Class 4; limited to consumer/industrial single-stroke events | Select only for cost-sensitive, non-safety-critical 24 V systems with infrequent surges and adequate board-level heatsinking. |
| SMCJ78A | PPP = 1500 W, SMC package, RθJC ≈ 10 °C/W, same VWM but higher VC (127 V min) | Meets IEC 61000-4-5 Class 2–3 but fails DO-160F Waveform 4 Level 4; lacks AEC-Q101 qualification | Use where aerospace certification is not required and surge repetition rate is low; verify thermal margin with actual layout. |
Compared with SMBJ78A and SMCJ78A, MAPLAD18KP78AE3 delivers 30× higher peak power handling, 14× lower thermal resistance, and formal qualification for aviation and automotive safety standards - making it the only choice for multi-stroke lightning resilience and mission-critical thermal stability.
Availability
MAPLAD18KP78AE3 is available at Aetrix Electronics and suitable for aerospace avionics, automotive engine control, and industrial motor drive applications requiring stable component supply, long-term lifecycle support, and traceable sourcing for safety-critical designs.
Supply support for MAPLAD18KP78AE3 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 MAPLAD series was developed to address multi-stroke lightning and load dump protection in harsh-environment electronics, combining ultra-high-power SMT packaging with AEC-Q101 and DO-160 compliance for next-generation vehicle and aircraft systems.
FAQ
What is the clamping voltage of MAPLAD18KP78AE3 at its rated peak pulse current?
The MAPLAD18KP78AE3 has a maximum clamping voltage (VC) of 126 V when subjected to a 100 A peak impulse current under 10/1000 μs waveform conditions. This value is guaranteed across the operating temperature range and ensures downstream components remain within safe voltage limits during surge events. The clamping performance is validated per Figure 3 in RF01215 Rev B.
Is MAPLAD18KP78AE3 suitable for bidirectional surge protection?
No, MAPLAD18KP78AE3 is a unidirectional TVS diode, with cathode connected to the metal base. For bidirectional protection, the equivalent part is MPLAD18KP78CA. Using MAPLAD18KP78AE3 in AC or reversible-polarity circuits risks reverse breakdown failure; polarity alignment must be verified in schematic and layout.
Does MAPLAD18KP78AE3 require a heatsink for continuous operation?
MAPLAD18KP78AE3 does not require an external heatsink for transient suppression, but its metal base must be soldered to a minimum 100 mm² PCB copper area for thermal management. Steady-state power dissipation is only 2.5 W at 25 °C ambient; however, thermal design must follow the derating curve in Figure 3 of RF01215 Rev B when ambient exceeds 70 °C.
What certifications does MAPLAD18KP78AE3 hold?
MAPLAD18KP78AE3 is qualified to AEC-Q101 for automotive use and meets RTCA DO-160F Section 22 for multi-stroke lightning. It also complies with IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT), and IEC 61000-4-5 (lightning) with 42 Ω source impedance. RoHS compliance is confirmed by the "e3" suffix per J-STD-020B Level 1 moisture sensitivity.
How is the polarity marked on MAPLAD18KP78AE3?
The polarity of MAPLAD18KP78AE3 is defined by its physical construction: the cathode is the entire metal base (bottom side), and the anode is the top-side metallized terminal. There is no visible polarity marking on the body; orientation must be confirmed using the pad layout in RF01215 Rev B and verified with continuity testing to the base before assembly. Incorrect mounting renders the device nonfunctional.
MAPLAD18KP78AE3 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
MAPLAD18KP78AE3 FAQ
1.How can I place an order for MAPLAD18KP78AE3 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAPLAD18KP78AE3 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 MAPLAD18KP78AE3 reliable?
The price and inventory of MAPLAD18KP78AE3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAPLAD18KP78AE3 is usually 5 days.
3.What payment methods are accepted for MAPLAD18KP78AE3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAPLAD18KP78AE3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAPLAD18KP78AE3?
MAPLAD18KP78AE3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAPLAD18KP78AE3 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 MAPLAD18KP78AE3?
For technical support, including MAPLAD18KP78AE3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAPLAD18KP78AE3 requirements.
6.How does Aetrix verify that MAPLAD18KP78AE3 is sourced from the original manufacturer or authorized distributors?
All MAPLAD18KP78AE3 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 MAPLAD18KP78AE3 meets industry standards.
7.What is the process for return or replacement of MAPLAD18KP78AE3?
All MAPLAD18KP78AE3 units undergo pre-shipment inspection (PSI). If there is an issue with MAPLAD18KP78AE3, 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 MAPLAD18KP78AE3 part is unused and in its original packaging.
Return procedure for MAPLAD18KP78AE3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAPLAD18KP78AE3 Tags
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