Microchip Technology 1N6940UTK3/TR

Overview

1N6940UTK3 from Microsemi is a hermetically sealed, ceramic-molybdenum ThinKey™ 3 surface-mount Schottky diode with anode-to-strap polarity, 15 V working peak reverse voltage, 150 A average rectified output current at TC = +100 °C, and 0.25 °C/W thermal resistance junction-to-case (anode-to-strap), designed for high-density aerospace power conversion and thermal-critical defense rectification.

For engineers reviewing the 1N6940UTK3 datasheet, 1N6940UTK3 pinout, 1N6940UTK3 application, or 1N6940UTK3 equivalent, key selection criteria include its MIL-PRF-19500/726 qualification level (JAN/JANTX/JANTXV), low forward voltage (0.43 V @ 75 A pk, TC = +25 °C), rugged strap-based thermal path, and strapless variant availability upon request.

Technical Context

This device implements an oxide-passivated, guard-ringed epitaxial Schottky structure to minimize forward voltage drop while enhancing reverse energy capability and surge robustness. Its anode-to-strap configuration establishes a direct low-inductance thermal conduction path from the silicon junction to the external heatsink via the metal strap.

The ThinKey™ 3 package enables double-side cooling and eliminates wire bonds, supporting high-reliability operation across -65 °C to +150 °C junction temperature range. It is qualified per MIL-PRF-19500/726 with JEDEC-registered 1N6940 numbering and supports up-screening for mission-critical applications.

Key Specifications

Pinout & Package

Package: Ceramic-molybdenum ThinKey™ 3 surface-mount package with anode-to-strap polarity; hermetically sealed, low-profile construction; weight ≈ 1.7 g; terminals plated with tin/lead or RoHS-compliant matte tin (commercial grade only).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current Schottky rectifier applications.

Compared with VSKY15015 and SD15015S, the 1N6940UTK3 delivers superior thermal resistance (0.25 °C/W), hermetic reliability, and full MIL-PRF-19500 qualification-making it the only choice for flight hardware, naval radar, and other safety-critical defense systems demanding proven long-term parametric stability.

Availability

1N6940UTK3 is available at Aetrix Electronics and suitable for aerospace power conversion, defense radar modulators, and MIL-STD-704 aircraft power systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for 1N6940UTK3 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, discrete devices, and RF solutions for aerospace, defense, and industrial markets.

The 1N6940UTK3 belongs to Microsemi's ThinKey™ Schottky diode product line, engineered specifically for high-power, high-reliability rectification in thermally constrained and mission-critical environments where hermeticity, surge immunity, and qualification integrity are non-negotiable.

FAQ

What is the thermal resistance junction-to-case for 1N6940UTK3, and how does it impact heatsink design?

The 1N6940UTK3 has a thermal resistance junction-to-case (RθJC) of 0.25 °C/W when measured anode-to-strap. This exceptionally low value directly enables compact heatsink sizing and passive cooling in space-constrained aerospace enclosures. Because the anode is bonded to the metal strap, thermal energy transfers efficiently to the external heatsink without relying on PCB copper layers-making 1N6940UTK3 ideal for double-side cooled assemblies where both strap and cathode surfaces contact thermal interfaces.

Is 1N6940UTK3 qualified to MIL-PRF-19500/726, and what reliability levels are offered?

Yes, the 1N6940UTK3 is qualified per MIL-PRF-19500/726 for Schottky diodes. It is available in JAN, JANTX, and JANTXV reliability levels-each including rigorous screening such as temperature cycling, burn-in, and parameter verification. The JANTXV level adds radiation hardness assurance and extended lot traceability, making 1N6940UTK3 suitable for launch-critical avionics and strategic defense platforms where failure is not an option.

What is the forward voltage of 1N6940UTK3 at high current and elevated temperature?

At 150 A peak forward current and case temperature of +125 °C, the 1N6940UTK3 exhibits a forward voltage (VF3) of 0.43 V. This low, stable VF under extreme thermal and electrical stress reflects its epitaxial Schottky construction and oxide passivation-key to minimizing conduction losses in high-efficiency power supplies used in radar transmitters and satellite power systems where thermal runaway must be avoided.

Does 1N6940UTK3 support cathode-to-strap polarity, and how is it designated?

No-the 1N6940UTK3 specifically denotes anode-to-strap polarity (AS suffix). For cathode-to-strap configuration, Microsemi offers the 1N6940UTK3CS variant. The AS/CS designation is part of the official nomenclature and determines thermal path orientation and PCB layout requirements. Using the wrong polarity variant risks improper heatsinking and thermal overload, so designers must verify the suffix and corresponding pad layout before committing to production.

Can 1N6940UTK3 be used without the metal strap, and how is that ordered?

Yes-Microsemi offers a strapless version of this device by special request, designated as 1N6940UTK3 (no AS/CS suffix). The strapless variant retains the same electrical ratings and ThinKey™ 3 footprint but removes the metal strap to accommodate alternative mechanical mounting or conformal coating requirements. Ordering requires direct coordination with Microchip (ex-Microsemi) sales or authorized distributors, as it is not stocked standard and may involve minimum order quantities or extended lead times.