Microchip Technology 1N6628U

Overview

1N6628U from Microsemi is a voidless-hermetically-sealed surface-mount ultrafast recovery glass rectifier diode rated for 660 V minimum breakdown voltage, 2.3 A average forward current at T_EC = +110°C, and 30 ns low-current reverse recovery time (t_rr). It serves as a high-reliability power conversion component in military-grade switching power supplies requiring controlled avalanche capability and radiation hardness.

For engineers reviewing the 1N6628U datasheet, 1N6628U pinout, 1N6628U application, or 1N6628U equivalent, this part delivers verified ultrafast switching performance, hermetic glass packaging for harsh-environment operation, and MIL-PRF-19500/590 qualification - critical for aerospace, defense, and nuclear instrumentation designs where failure tolerance is non-negotiable.

Technical Context

This device implements a Category I metallurgical bond within a voidless hard-glass package with tungsten slugs and copper end caps, enabling stable junction-to-endcap thermal resistance of 6.5°C/W and operation from –65°C to +150°C. Its triple-layer passivation and controlled avalanche behavior support peak reverse power handling without degradation under transient overvoltage conditions.

The 1N6628U exhibits 1.35 V forward voltage at 2.0 A (25°C) and 1.50 V at 4.0 A (150°C), with capacitance of 40 pF at 10 V reverse bias. Reverse leakage remains ≤2.0 µA at 600 V VRWM and ≤500 µA at 150°C - confirming suitability for high-temperature, low-leakage DC-DC conversion stages.

Key Specifications

Pinout & Package

Package: Hermetically sealed voidless hard-glass "Package E" (also designated D-5B), with copper end caps having Sn/Pb finish and cathode band marking. Dimensions: 7.32 mm × 3.94 mm × 1.78 mm (L × W × H); weight: 539 mg.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast recovery rectifier applications.

Compared with 1N6628U, the 1N6628US offers identical performance with formalized military traceability, while the VS-2EYH06-M3/45 trades hermetic reliability and radiation tolerance for lower cost and wider commercial availability - making it unsuitable for environments demanding MIL-PRF-19500/590 compliance.

Availability

1N6628U is available at Aetrix Electronics and suitable for aerospace power distribution, military radar transmitter supplies, nuclear instrumentation front-ends, and avionics flight control power systems requiring stable component supply and full MIL-PRF-19500/590 traceability.

Supply support for 1N6628U 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 (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for defense, aerospace, and industrial markets.

The 1N6628U belongs to Microsemi's military-qualified ultrafast recovery rectifier family, engineered specifically for applications where hermetic sealing, radiation tolerance, and guaranteed avalanche performance are mandatory design requirements.

FAQ

What is the maximum working peak reverse voltage (VRWM) for the 1N6628U?

The 1N6628U has a working peak reverse voltage (VRWM) of 600 V, derived from its 660 V minimum breakdown voltage with standard safety margin. This rating is valid across the full operating temperature range of –65°C to +150°C and is confirmed in the Electrical Characteristics table under the VRWM column for 1N6628US - a functionally identical variant. The 1N6628U maintains this VRWM without derating up to +150°C junction temperature.

Is the 1N6628U hermetically sealed, and what does "voidless" mean in this context?

Yes, the 1N6628U uses a voidless hermetically sealed hard-glass package with tungsten slugs and copper end caps. "Voidless" means the glass-to-metal seal contains no internal air pockets or micro-cavities - eliminating pathways for moisture ingress, outgassing, or thermal expansion mismatch. This construction meets MIL-PRF-19500/590 Category I requirements and ensures long-term reliability in vacuum, high-humidity, or radiation-intensive environments.

Does the 1N6628U have radiation hardness certification, and what level is validated?

Yes, the 1N6628U is inherently radiation hard as documented in Microsemi MicroNote 050. It exhibits no parametric shift up to 100 krad(Si) total ionizing dose (TID), with no latch-up or functional failure observed. This radiation tolerance stems from its hermetic glass package, silicon process, and Category I metallurgical bond - making it suitable for nuclear instrumentation, satellite power systems, and reactor monitoring equipment.

What is the thermal resistance junction-to-endcap (RθJEC) for the 1N6628U, and how is it used in thermal design?

The 1N6628U has a specified thermal resistance of 6.5°C/W from junction to endcap (R_θJEC). This value enables direct thermal modeling from die to externally mounted heatsink or chassis via the copper end caps. Unlike standard SMD diodes relying on PCB copper for heat dissipation, the 1N6628U's low R_θJEC allows endcap-to-chassis conduction - critical for high-power density designs where PCB area is constrained and ambient temperatures exceed 85°C.

Can the 1N6628U be used as a drop-in replacement for the axial-leaded 1N6628 in existing designs?

No, the 1N6628U is not a drop-in replacement for the axial-leaded 1N6628 due to fundamental package differences: the 1N6628U uses surface-mount Package E (D-5B), while the 1N6628 uses DO-41 axial leads. Although both share identical electrical specifications (660 V V_BR, 2.3 A I_O, 30 ns t_rr), the 1N6628U requires re-layout for SMD pads and endcap thermal mounting - no PCB changes are possible without redesign. Refer to the separate data sheet for 1N6626 thru 1N6631 for axial-leaded variants.