Microchip Technology UM4001D

Overview

UM4001D from Microsemi is a high-power PIN diode designed for RF switching and attenuation in HF–S-band systems. It features 200 V reverse voltage rating, 0.5 Ω typical series resistance at 100 MHz/100 mA, >5 µs carrier lifetime, 3 pF capacitance at 100 V/1 MHz, and 37.5 W power dissipation in stud-mount configuration. It is used in UHF phase shifters and megawatt peak-power duplexers.

For engineers reviewing the UM4001D datasheet, UM4001D pinout, UM4001D application, or UM4001D equivalent, key selection criteria include reverse voltage capability, thermal path efficiency in stud-mounted packages, RF distortion performance under high bias current, and compatibility with automatic insertion equipment for high-volume microwave module assembly.

Technical Context

The UM4001D operates as a current-controlled RF resistor with low capacitance and high charge storage, enabling precise RF signal control using modest DC bias. Its thick I-region and long carrier lifetime (>5 µs) support stable conductance over wide frequency ranges (HF to S-band) while maintaining low distortion in attenuator and switch topologies.

Thermally, the "D" package uses a stud-mount configuration with 6 °C/W thermal resistance at 25 °C stud temperature, allowing 37.5 W continuous power dissipation. It is electrically equivalent to UM4901 but differs in thermal path length and mounting interface-UM4001D uses a longer thermal path than UM4901D, resulting in lower power rating under identical conditions.

Key Specifications

Pinout & Package

The UM4001D is a two-terminal stud-mounted PIN diode housed in a metal-ceramic "D" package with an isolated anode stud and cathode flange. Thermal path is optimized via direct stud-to-heatsink contact.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-power RF switching applications.

Compared with UM4001D, UM4901D offers improved thermal efficiency in identical packaging, while UMX4001D delivers identical RF behavior with compliant surface finish-both retain full pin and functional equivalence but address distinct thermal or regulatory requirements.

Availability

UM4001D is available at Aetrix Electronics and suitable for UHF phase shifters, megawatt peak-power duplexers, antenna selector networks, and RF filter tuning switches requiring stable component supply across extended production lifecycles.

Supply support for UM4001D 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 RF components for defense, aerospace, and communications infrastructure.

The UM4000/UM4900 series was developed specifically for high-power RF switching and attenuation in mission-critical radar, EW, and satellite ground systems where distortion, thermal stability, and long-term reliability are non-negotiable.

FAQ

What is the maximum reverse voltage rating for UM4001D?

The UM4001D has a reverse voltage rating of 200 V at 10 µA leakage current. This rating is verified per Microsemi's absolute maximum ratings table and supports operation in high-peak-voltage RF environments such as pulsed radar duplexers. The UM4001D maintains reliable blocking behavior up to this voltage under specified thermal conditions, and its thick I-region prevents premature avalanche breakdown.

Does UM4001D require a heatsink, and what is its thermal resistance?

Yes, UM4001D requires a heatsink when operated near its 37.5 W power dissipation limit. Its thermal resistance is 6 °C/W when mounted to a heatsink at 25 °C stud temperature (Condition D). Proper thermal interface material and flatness of the stud surface are critical to achieving this rating-deviations increase junction temperature and reduce safe operating area.

Is UM4001D compatible with RoHS-compliant manufacturing processes?

Standard UM4001D uses Sn/Pb finish and is not RoHS-compliant. However, the RoHS-compliant version UMX4001D is available with matte tin plating and meets EU Directive 2002/95/EC. Both share identical electrical, thermal, and mechanical specifications-only the finish differs. UMX4001D is drop-in compatible in all assembly processes qualified for matte tin.

How does UM4001D differ from UM4001SM in terms of RF performance?

UM4001D and UM4001SM share identical core die characteristics-same 200 V rating, 0.5 Ω R_S, >5 µs τ, and 3 pF C_T. Their RF performance is electrically equivalent. The difference lies solely in packaging: UM4001D uses a stud-mount metal-ceramic case for high-power thermal anchoring, while UM4001SM is a surface-mount variant with different thermal path and layout constraints.

Can UM4001D be used in S-band (2–4 GHz) applications?

Yes, UM4001D is qualified for use through S-band frequencies. Its low capacitance (3 pF), high parallel resistance (>10 kΩ), and stable series resistance across frequency enable effective RF switching and attenuation up to at least 3 GHz, as confirmed by Microsemi's typical performance graphs and qualification in S-band phase shifters and duplexers.