Microchip Technology 1N5661

Overview

1N5661 from Microchip Technology is a unidirectional transient voltage suppressor (TVS) diode in a hermetically sealed DO-13 metal package, designed for high-energy surge protection in aerospace, avionics, and industrial systems. It features a 121 V rated standoff voltage (VWM), 135 V minimum breakdown voltage (V(BR)), 215 V maximum clamping voltage (VC) at 7.0 A peak pulse current (IPP), and 1500 W peak pulse power rating per 10/1000 µs waveform.

For engineers reviewing the 1N5661 datasheet, 1N5661 pinout, 1N5661 application, or 1N5661 equivalent, this device is selected for robust secondary lightning protection (IEC61000-4-5 Class 1–4), ESD/EFT hardening (IEC61000-4-2/-4), and fast-clamp (<100 ps) suppression of inductive switching transients in harsh-environment power rails and signal lines.

Technical Context

The 1N5661 operates as a unidirectional avalanche diode, entering controlled breakdown above its 121 V standoff threshold to clamp transient overvoltages while maintaining low leakage (<5 µA at VWM). Its hermetic DO-13 package ensures stable performance across -55°C to +175°C operating temperature range and inherent radiation hardness per MicroNote 050.

It delivers 1500 W non-repetitive peak pulse power with <100 ps response time, enabling protection against ESD, EFT, and induced RF transients. The cathode is internally connected to the metal case, requiring proper grounding in PCB layout to ensure effective clamping path and thermal dissipation via lead-to-junction thermal resistance of 50°C/W.

Key Specifications

Pinout & Package

Package: DO-13 (DO-202AA), hermetically sealed metal-glass case with tin-lead plated leads. Cathode terminal is electrically connected to the metal case and marked by a diode symbol on the body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMCJ120A and 1N5661A, the 1N5661 offers optimal trade-off between rugged through-hole mounting, hermetic reliability, and cost-effective commercial-grade surge protection-making it preferred for legacy avionics upgrades and industrial retrofit programs where reworkability and long-term availability matter.

Availability

1N5661 is available at Aetrix Electronics and suitable for aerospace power bus protection, industrial motor drive control, avionics sensor interface, and military communications equipment requiring stable component supply and long-lifecycle support.

Supply support for 1N5661 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

Microchip Technology (formerly Microsemi) is a global semiconductor company specializing in high-reliability analog, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The 1N5661 belongs to Microchip's legacy JAN/JANTXV-qualified TVS diode family, engineered specifically for mission-critical transient suppression in environments where hermeticity, temperature resilience, and ESD/lightning immunity are non-negotiable.

FAQ

What is the maximum clamping voltage of the 1N5661 under standard test conditions?

The 1N5661 exhibits a maximum clamping voltage (VC) of 215 V when subjected to a 10/1000 µs surge waveform with a peak pulse current (IPP) of 7.0 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. The 1N5661 maintains this clamping performance consistently due to its stable avalanche characteristics and hermetic DO-13 package.

Is the 1N5661 suitable for IEC61000-4-5 secondary lightning protection?

Yes, the 1N5661 is validated for secondary lightning protection per IEC61000-4-5 across multiple classes: Class 1 (42 Ω source) up to 1N5665A, Class 2 (42 Ω) up to 1N5663A, and Class 4 (2 Ω) up to 1N5636A. Its 1500 W peak pulse rating and sub-100 ps response enable reliable suppression of lightning-induced surges in avionics and industrial control systems. The 1N5661 itself supports Class 1–2 configurations with 42 Ω source impedance.

Does the 1N5661 have military qualification options?

Yes, the 1N5661A variant is available with JAN, JANTX, or JANTXV prefixes (e.g., JANTXV1N5661A) and qualified per MIL-PRF-19500/500 for tighter parametric tolerances and extended environmental testing. These versions retain the same DO-13 hermetic package and electrical performance as the commercial 1N5661 but include full traceability, screening, and radiation hardness documentation required for defense and space programs.

How does the DO-13 package of the 1N5661 compare to plastic TVS diodes in reliability-critical applications?

The DO-13 package of the 1N5661 uses welded metal-glass hermetic sealing, offering superior moisture resistance, thermal stability (-55°C to +175°C), and long-term parameter stability versus plastic axial-leaded equivalents like the 1N6267 series. Its tin-lead plated leads ensure solderability per MIL-STD-750, and the cathode-to-case connection provides a low-inductance ground path essential for fast transient suppression. This makes the 1N5661 preferred in avionics and downhole oilfield electronics where field failure is unacceptable.

What is the standby leakage current specification for the 1N5661 at its rated standoff voltage?

The 1N5661 specifies a maximum standby leakage current (ID) of 5 µA when biased at its rated standoff voltage (VWM) of 121 V and ambient temperature of 25°C. This ultra-low leakage ensures minimal power drain in always-on systems and prevents false triggering in high-impedance sensing circuits. The 1N5661 maintains this performance across its full operating temperature range due to stable junction characteristics and hermetic packaging.