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Microchip Technology 1N8178US/TR
- Part No.:
- 1N8178US/TR
- Manufacturer:
- Microchip Technology
- Category:
- TVS Diodes
- Package:
- SQ-MELF, A
- Datasheet:
-
1N8178US/TR.pdf
- Description:
- LOW CAPACITANCE TVS
- Quantity:
- Payment:
- Shipping:
Inventory:4,666
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Product details
Overview
1N8178US/TR from Microsemi is a voidless-hermetically-sealed unidirectional transient voltage suppressor (TVS) with 4 pF capacitance, 120 V working standoff voltage (VWM), and 150 W peak pulse power at 10/1000 µs. It features internal Category 1 metallurgical bonds, triple-layer passivation, and RoHS-compliant construction for high-reliability aerospace and defense signal-line protection.
For engineers reviewing the 1N8178US/TR datasheet, 1N8178US/TR pinout, 1N8178US/TR application, or 1N8178US/TR equivalent, this device delivers low-capacitance ESD/EFT protection per IEC61000-4-2/4-4, secondary lightning protection per IEC61000-4-5, and radiation-hardened performance validated per MicroNote 050 - critical for avionics data links and MIL-STD-750 qualified systems.
Technical Context
The 1N8178US/TR employs a unique series-connected rectifier diode opposite the TVS junction to achieve ultra-low 4 pF capacitance while maintaining unidirectional clamping behavior. Its hard-glass hermetic package ensures zero voids and stable thermal resistance (150 °C/W) under surge conditions.
It operates across –55 °C to +175 °C junction temperature range, supports 120 V DC standoff, clamps at ≤208 V under 300 A peak impulse current (IPP), and exhibits <0.5 µA standby leakage at rated VWM - enabling robust protection of high-frequency RF front-ends and serial data interfaces without signal integrity degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 120 V - maximum continuous reverse-bias voltage before breakdown; sets safe operating margin for protected line. |
| VC @ IPP=300 A | 208 V - clamping voltage during 10/1000 µs surge; defines worst-case overvoltage seen by downstream circuitry. |
| CT | 4 pF - total terminal capacitance at 0 V; enables use in >1 GHz RF paths and high-speed serial links (e.g., RS-485, CAN FD). |
| PPP | 150 W - peak pulse power rating; sustains single-event transients up to 300 A without failure. |
| TJ Range | –55 °C to +175 °C - extended thermal envelope supporting operation in engine bays, space-grade enclosures, and sealed military housings. |
| ID @ VWM | 0.5 µA - ultra-low leakage at rated standoff; prevents false triggering and minimizes static power loss in battery-powered systems. |
| RθJA | 150 °C/W - thermal resistance from junction to ambient; requires minimal PCB copper area for thermal management in through-hole layouts. |
Pinout & Package
Package: Axial-leaded, voidless hermetically sealed hard-glass case with tungsten slugs; cathode band marking; RoHS-compliant matte tin plating over copper leads; weight ≈ 340 mg.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink path during forward conduction | Connected to protected line; conducts surge energy into ground when clamped. |
| Cathode | Reference terminal with polarity band | Connected to system ground; establishes unidirectional clamping direction (cathode-to-anode voltage must not exceed VWM). |
Key Features
| Feature | Design Value |
|---|---|
| Category 1 metallurgical bond | Internal bond structure qualified per MIL-STD-883 for high-reliability applications including spaceflight and nuclear instrumentation. |
| Triple-layer passivation | Hermetic glass encapsulation with three dielectric layers prevents moisture ingress and ion migration under high-humidity or salt-spray environments. |
| Lowest capacitance for 150 W TVS | 4 pF enables direct integration into RF amplifier input stages and GPS L1/L2 antenna feeds without detuning or insertion loss. |
| Radiation hardness | Inherently radiation-tolerant per Microsemi MicroNote 050; suitable for low-earth orbit (LEO) satellite telemetry receivers and nuclear facility control systems. |
Applications
| Aerospace Data Bus Protection | Military Radio Front-End |
|---|---|
Use Scenario: Protecting ARINC 429 or MIL-STD-1553B data lines from induced lightning transients on aircraft avionics racks. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between bus driver output and connector interface. Use Value: 4 pF capacitance avoids signal edge degradation at 1 Mbps data rates; 208 V clamping limits bus voltage excursion below receiver absolute max rating. | Use Scenario: Shielding HF/VHF transceiver RF input stages from ESD events during field deployment and antenna coupling. IC Role / Device Role / Timing Role: Low-capacitance shunt protector mounted directly at SMA connector feedthrough. Use Value: Sub-5 pF loading preserves impedance match and noise figure; 150 W rating absorbs handheld ESD gun discharges (±15 kV contact) without degradation. |
| Satellite Telemetry Receiver | Nuclear Instrumentation Signal Chain |
Use Scenario: Guarding S-band downlink receivers against single-event transients in low-earth orbit missions. IC Role / Device Role / Timing Role: Radiation-hardened TVS on LNA bias and IF output lines. Use Value: Inherent TID tolerance and SEE immunity per MicroNote 050 eliminate need for additional shielding; 175 °C max TJ supports passive thermal design in vacuum. | Use Scenario: Safeguarding analog sensor outputs (e.g., neutron flux detectors) in reactor containment buildings exposed to gamma radiation and humidity. IC Role / Device Role / Timing Role: Hermetic TVS on signal conditioning amplifier inputs. Use Value: Voidless glass seal prevents internal condensation; Category 1 bond ensures long-term reliability under 10⁶ rad(Si) total ionizing dose. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMCJ120A | Surface-mount DO-214AB package; 6.5 pF capacitance; 120 V VWM; 1500 W PPP rating. | Higher power handling but larger capacitance limits use in >500 MHz circuits; unsuitable for hermetic or radiation-hardened requirements. | Select only for cost-sensitive commercial industrial designs where radiation hardness and ultra-low capacitance are not required. |
| 1N6330 | Axial-leaded glass package; 120 V VWM; 150 W PPP; 10 pF capacitance; no Category 1 bond or radiation qualification. | Lacks triple-layer passivation and voidless seal; not rated for aerospace or nuclear environments. | Acceptable for non-critical telecom surge protection where 10 pF loading is tolerable and radiation tolerance is unnecessary. |
Compared with SMCJ120A and 1N6330, the 1N8178US/TR uniquely combines 4 pF capacitance, hermetic Category 1 bonding, and radiation hardness - making it irreplaceable in RF-intensive, mission-critical systems where signal fidelity and long-term reliability under extreme stress are non-negotiable.
Availability
1N8178US/TR is available at Aetrix Electronics and suitable for aerospace data buses, military radio front-ends, satellite telemetry receivers, and nuclear instrumentation signal chains requiring stable component supply with full traceability and long-lifecycle support.
Supply support for 1N8178US/TR 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, radiation-hardened, and security-focused analog and mixed-signal ICs and discrete components.
The 1N8178US/TR belongs to Microsemi's legacy high-reliability TVS family designed specifically for defense, aerospace, and nuclear applications where failure is not an option - emphasizing hermetic sealing, ultra-low capacitance, and proven survivability under extreme environmental stress.
FAQ
What is the clamping voltage of the 1N8178US/TR under a 300 A surge?
The 1N8178US/TR clamps at a maximum of 208 V when subjected to a 300 A peak impulse current with a 10/1000 µs waveform. This value is specified in the Electrical Characteristics table on page 3 of the Microsemi datasheet and represents the upper limit of voltage seen by protected circuitry during worst-case transient events - critical for ensuring downstream components remain within their absolute maximum ratings.
Is the 1N8178US/TR RoHS compliant?
Yes, the 1N8178US/TR is RoHS compliant, as confirmed by its "e3" suffix in the part nomenclature and explicit statement in the FEATURES section of the datasheet. The axial leads use matte tin plating over copper, and the voidless hermetic glass package contains no restricted substances above threshold limits - meeting EU Directive 2011/65/EU requirements for environmentally conscious manufacturing.
Does the 1N8178US/TR support bidirectional transient protection?
No, the 1N8178US/TR is strictly unidirectional. Bidirectional protection requires two 1N8178US/TR devices mounted in anti-parallel configuration, as shown in Figure 5 of the datasheet. This arrangement doubles the effective capacitance to 8 pF but provides symmetrical clamping for AC-coupled or differential signal lines such as RS-422 or LVDS interfaces.
What is the maximum operating temperature for the 1N8178US/TR?
The 1N8178US/TR supports a junction temperature range of –55 °C to +175 °C, verified per the Maximum Ratings table on page 2 of the datasheet. This extended thermal envelope allows deployment in engine-mounted avionics, sealed nuclear control cabinets, and space-grade payloads without derating - provided thermal resistance to ambient remains ≤150 °C/W via appropriate PCB layout.
How does the 4 pF capacitance of the 1N8178US/TR benefit high-frequency applications?
The 4 pF capacitance of the 1N8178US/TR minimizes signal distortion and insertion loss in RF and high-speed digital paths. At 1 GHz, its capacitive reactance exceeds 40 Ω, preventing significant loading of 50 Ω transmission lines - enabling direct placement on GPS antenna feeds, radar receiver inputs, and 1 Gbps Ethernet PHY interfaces without compromising bandwidth or return loss.
1N8178US/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Package/Case:
- SQ-MELF, A
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 110V
- Voltage - Breakdown (Min):
- 124V
- Voltage - Clamping (Max) @ Ipp:
- 183V
- Current - Peak Pulse (10/1000µs):
- 820mA
- Power - Peak Pulse:
- 150W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- A, SQ-MELF
1N8178US/TR FAQ
1.How can I place an order for 1N8178US/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N8178US/TR 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 1N8178US/TR reliable?
The price and inventory of 1N8178US/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N8178US/TR is usually 5 days.
3.What payment methods are accepted for 1N8178US/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N8178US/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N8178US/TR?
1N8178US/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N8178US/TR 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 1N8178US/TR?
For technical support, including 1N8178US/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N8178US/TR requirements.
6.How does Aetrix verify that 1N8178US/TR is sourced from the original manufacturer or authorized distributors?
All 1N8178US/TR 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 1N8178US/TR meets industry standards.
7.What is the process for return or replacement of 1N8178US/TR?
All 1N8178US/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N8178US/TR, 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 1N8178US/TR part is unused and in its original packaging.
Return procedure for 1N8178US/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N8178US/TR Tags
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