Microchip Technology MX1N8179US/TR

Overview

MX1N8179US/TR from Microsemi is a voidless-hermetically-sealed unidirectional transient voltage suppressor (TVS) with 4 pF capacitance, 138 V working standoff voltage (VWM), and 150 W peak pulse power at 10/1000 µs. It features internal Category 1 metallurgical bonds and low-leakage performance (0.5 µA max ID), designed for ESD/EFT protection in high-frequency RF front-ends and aerospace-grade signal lines.

For engineers reviewing the MX1N8179US/TR datasheet, MX1N8179US/TR pinout, MX1N8179US/TR application, or MX1N8179US/TR equivalent, key selection criteria include clamping voltage (208 V), surge current rating (300 A), RoHS-compliant MELF "A" package, and IEC61000-4-2/4-4 compliance for mission-critical transient suppression.

Technical Context

This TVS uses a unique series-connected rectifier diode opposing the avalanche junction to achieve ultra-low 4 pF capacitance while maintaining unidirectional operation. Its hard-glass hermetic construction ensures radiation hardness per MicroNote 050 and immunity to MIL-STD-750 Method 1020 ESD.

The device operates across –55 °C to +175 °C junction temperature, with thermal resistance of 150 °C/W and derated power above 25 °C ambient. Clamping occurs at 208 V under 300 A 10/1000 µs surge, delivering robust secondary lightning protection per select IEC61000-4-5 levels.

Key Specifications

Pinout & Package

Package: Hermetically sealed voidless hard-glass MELF "A" package with tungsten slugs and axial leads; RoHS-compliant matte tin plating over copper; cathode band marking; weight ≈ 340 mg.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ130A and 1N6320US, MX1N8179US/TR uniquely combines 4 pF capacitance, 138 V VWM, Category 1 bonding, and full –55 °C to +175 °C operation-making it the only option qualified for RF-critical, high-reliability aerospace and medical imaging systems.

Availability

MX1N8179US/TR is available at Aetrix Electronics and suitable for RF transceiver front-ends, aerospace avionics signal lines, and medical imaging detector interfaces requiring stable component supply and long-term obsolescence management.

Supply support for MX1N8179US/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 analog and mixed-signal ICs, RF solutions, and radiation-hardened components for defense, aerospace, and industrial markets.

The 1N8149–1N8182 series was engineered specifically for ultra-low-capacitance transient suppression in high-frequency, high-reliability signal chains-addressing ESD, EFT, and secondary lightning threats where conventional TVS diodes introduce unacceptable bandwidth loss.

FAQ

What is the maximum clamping voltage of MX1N8179US/TR under a 300 A 10/1000 µs surge?

The MX1N8179US/TR has a maximum clamping voltage (VC) of 208 V when subjected to a 300 A peak impulse current with a 10/1000 µs waveform. This value is measured at 25 °C ambient and defines the upper voltage limit imposed on protected circuits during worst-case transients. The MX1N8179US/TR maintains this clamping performance across its full operating temperature range due to its stable avalanche characteristics and hermetic packaging.

Is MX1N8179US/TR compliant with RoHS and qualified for aerospace applications?

Yes, MX1N8179US/TR is RoHS compliant (e3 marking) and qualified for aerospace use via its MX prefix, indicating JANTX-level reliability screening per MIL-PRF-19500. It features Category 1 internal metallurgical bonds, voidless hermetic glass sealing, and radiation hardness per Microsemi MicroNote 050-making MX1N8179US/TR suitable for flight-critical avionics and satellite subsystems.

How does the 4 pF capacitance of MX1N8179US/TR compare to standard TVS diodes?

The 4 pF capacitance of MX1N8179US/TR is among the lowest available for a 150 W TVS, achieved through a proprietary series-connected rectifier diode architecture. Standard unidirectional TVS diodes in similar power classes typically exhibit 50–200 pF, which degrades signal integrity above ~100 MHz. MX1N8179US/TR's 4 pF enables direct placement on 1–3 GHz RF traces without impedance mismatch or insertion loss penalties.

What is the working standoff voltage (VWM) and why is it critical for MX1N8179US/TR selection?

The MX1N8179US/TR has a working standoff voltage (VWM) of 138 V-the maximum continuous reverse voltage it can block while maintaining ≤0.5 µA leakage. This parameter is critical because it must exceed the normal operating voltage of the protected line by ≥10% to prevent false triggering, yet remain below the insulation rating of downstream components. For example, MX1N8179US/TR is ideal for 100–120 V bias rails in RF power amplifiers.

Can MX1N8179US/TR be used in bidirectional configurations?

MX1N8179US/TR is inherently unidirectional, but bidirectional protection can be implemented using two MX1N8179US/TR devices in anti-parallel configuration as shown in Microsemi's Figure 5. This arrangement doubles the effective capacitance to 8 pF while preserving clamping symmetry. However, for true single-device bidirectional performance, alternate part numbers like MX1N8179DUS (if available) or dedicated bidirectional TVS families should be evaluated instead of MX1N8179US/TR.