Microchip Technology MS1N8158US/TR

Overview

MS1N8158US/TR from Microsemi is a voidless-hermetically-sealed unidirectional transient voltage suppressor (TVS) designed for high-reliability, high-frequency signal line protection. It delivers 150 W peak pulse power at 10/1000 µs, 4 pF capacitance, and a 17.0 V working standoff voltage (VWM), with clamping voltage of 27.7 V at 300 A IPP - ideal for ESD/EFT protection in aerospace data links and MIL-STD-750-compliant systems.

For engineers reviewing the MS1N8158US/TR datasheet, MS1N8158US/TR pinout, MS1N8158US/TR application, or MS1N8158US/TR equivalent, key selection criteria include low-capacitance transient suppression, Category 1 metallurgical bond reliability, hermetic glass package robustness, and compliance with IEC61000-4-2/4-4/4-5 standards for mission-critical electronics.

Technical Context

This TVS employs a unique series-connected rectifier diode in anti-parallel configuration with the avalanche junction to achieve ultra-low 4 pF capacitance while maintaining unidirectional operation. Its hard-glass hermetic construction uses internal tungsten slugs and Category 1 metallurgical bonds for radiation hardness and thermal stability across –55 °C to +175 °C.

The device operates with 0.5 µA maximum standby current at 17.0 V VWM and clamps to 27.7 V at 300 A peak impulse current (IPP), enabling reliable secondary lightning protection per IEC61000-4-5 Level 3–4 and ESD immunity per IEC61000-4-2 ±15 kV contact discharge.

Key Specifications

Pinout & Package

MS1N8158US/TR is housed in an axial-leaded, voidless-hermetically-sealed hard-glass package with cathode band marking. Package dimensions: BD = 0.060–0.085 in (1.52–2.16 mm), BL = 0.106–0.175 in (2.69–4.45 mm), LL = 0.800–1.300 in (20.32–33.02 mm). Leads are tin/lead or RoHS-compliant matte tin over copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ17A and 1N6322, MS1N8158US/TR provides 7× higher surge current capacity, 2.5× lower capacitance, and verified hermetic reliability for aerospace and nuclear applications - making it irreplaceable where failure is not an option.

Availability

MS1N8158US/TR is available at Aetrix Electronics and suitable for avionics data bus protection, MIL-STD-1553B interface hardening, and satellite telemetry front-end designs requiring stable component supply across extended production lifecycles.

Supply support for MS1N8158US/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 secure analog and mixed-signal ICs for defense, aerospace, and industrial markets.

The MS1N8158US/TR belongs to Microsemi's legacy 1N81xx series of hermetic TVS diodes, engineered specifically for mission-critical transient suppression where zero-failure tolerance, long-term parametric stability, and environmental resilience are mandatory.

FAQ

What is the maximum clamping voltage of MS1N8158US/TR under standard surge conditions?

The MS1N8158US/TR has a maximum clamping voltage (VC) of 27.7 V when subjected to a 10/1000 µs waveform with a peak impulse current (IPP) of 300 A. This value is measured at 25 °C ambient and defines the upper voltage limit imposed on protected circuitry during surge events. The MS1N8158US/TR maintains this clamping performance across its full operating temperature range due to its hermetic construction and stable avalanche characteristics.

Is MS1N8158US/TR compliant with RoHS and other environmental standards?

Yes, MS1N8158US/TR is offered in RoHS-compliant versions with matte tin plating over copper leads, satisfying Directive 2011/65/EU. It also meets MIL-STD-750 Method 1020 for ESD insensitivity and is inherently radiation-hardened per Microsemi MicroNote 050. The voidless hermetic glass package eliminates halogenated flame retardants and outgassing concerns common in epoxy-packaged alternatives.

How does the 4 pF capacitance of MS1N8158US/TR impact high-speed signal integrity?

The 4 pF total capacitance of MS1N8158US/TR minimizes loading on high-frequency signal paths, preserving rise times and eye diagrams in data rates exceeding 1 Gbps. Unlike conventional TVS devices with 10–30 pF, this low value prevents signal distortion in ARINC 429, RS-422, and MIL-STD-1553B interfaces. The MS1N8158US/TR achieves this via an integrated anti-parallel rectifier architecture that avoids parasitic junction capacitance trade-offs.

What is the significance of "Category 1 metallurgical bond" in MS1N8158US/TR?

"Category 1 metallurgical bond" refers to Microsemi's proprietary internal tungsten-slug bonding process used in MS1N8158US/TR, qualified to MIL-STD-750 Method 2032 for mechanical strength and thermal cycling endurance. This bond ensures no delamination or resistance shift under shock, vibration, or thermal stress - critical for avionics and space applications where repair is impossible. The MS1N8158US/TR's Category 1 bond contributes directly to its 20+ year field reliability claim.

Can MS1N8158US/TR be used for bidirectional transient protection?

No, MS1N8158US/TR is strictly unidirectional. For bidirectional protection, two MS1N8158US/TR units must be connected in anti-parallel configuration - as documented in Figure 5 of the datasheet - resulting in doubled capacitance (8 pF) but symmetric clamping behavior. This approach retains the device's low-capacitance advantage while enabling AC-coupled or differential line protection, unlike monolithic bidirectional TVS diodes which typically exceed 10 pF.