Microchip Technology UM4301D

Overview

UM4301D from Microsemi is a high-power, low-distortion PIN diode designed for RF switching and linear attenuator applications in HF–1 GHz systems. It features 100 V reverse voltage rating, 1.5 Ω max series resistance at 100 mA/100 MHz, 2.2 pF max capacitance at 100 V/1 MHz, 20 W power dissipation (stud temperature), and 250 µm minimum I-region width.

For engineers reviewing the UM4301D datasheet, UM4301D pinout, UM4301D application, or UM4301D equivalent, key selection criteria include its 100 V blocking capability, thermal resistance of 10 °C/W (stud mount), low distortion performance below 5 MHz transit time frequency, and compatibility with high-linearity RF control paths requiring stable resistance modulation.

Technical Context

The UM4301D employs a thick intrinsic region enabling low distortion in analog RF attenuation and precise RF switch control. Its carrier lifetime ≥6.0 µs and thermally matched construction support stable resistance modulation under RF signal conditions up to 1 GHz.

Designed for stud-mounted thermal management, it delivers 15 W continuous power dissipation at 25 °C stud temperature with θ_JA = 10 °C/W - optimized for high-reliability RF front-end modules where thermal stability and voltage hold-off are critical.

Key Specifications

Pinout & Package

UM4301D uses Style 'D' isolated stud package: anode and cathode terminals are electrically isolated from the metal stud base, enabling flexible grounding schemes in RF circuits. The stud serves as mechanical anchor and thermal path, not electrical connection.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF switching and attenuator applications.

Compared with UM4302D, UM4301D offers tighter voltage margin but identical thermal and RF linearity; versus UM7301D, it trades higher capacitance for significantly improved power handling and lower series resistance - making UM4301D optimal for high-power HF–UHF linear control where distortion and thermal stability are primary constraints.

Availability

UM4301D is available at Aetrix Electronics and suitable for HF transceiver attenuators, UHF T/R switch protection, RF test equipment routing, and avionics front-ends requiring stable component supply and long-lifecycle support.

Supply support for UM4301D 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 RF, microwave, and radiation-hardened components.

The UM4300 series was engineered specifically for high-linearity RF switching and precision attenuator applications in defense, aerospace, and communications infrastructure where low distortion, thermal robustness, and voltage integrity are non-negotiable.

FAQ

What is the maximum RF voltage the UM4301D can block in reverse bias?

The UM4301D is rated for 100 V reverse voltage at 10 µA leakage current. In RF switching applications, it reliably blocks peak RF voltages up to ~70 V RMS (100 V peak) without breakdown. This rating assumes proper thermal management via the stud mount and operation within the specified 25 °C stud temperature limit. Exceeding this voltage risks irreversible junction damage.

Does the UM4301D require a heatsink, and what thermal performance can be expected?

Yes - the UM4301D must be mounted to a heatsink via its isolated stud to achieve rated 15 W power dissipation. With a 10 °C/W thermal resistance (stud-to-heatsink), a 25 °C ambient and 25 °C stud temperature yield a maximum 15 W continuous dissipation. Without adequate heatsinking, power derating is required per the thermal impedance curves on page 3 of the datasheet.

How does the UM4301D differ from surface-mount versions like UM4301SM?

The UM4301D uses a stud-mounted Style 'D' package with electrically isolated terminals, optimized for high-power RF stages requiring direct thermal anchoring. In contrast, UM4301SM is a surface-mount variant with different footprint, lower power rating (15 W → 5.5 W), and higher thermal resistance (20 °C/W). They are not interchangeable without PCB and thermal redesign.

Can the UM4301D be used in linear attenuator configurations below 500 kHz?

Yes - the UM4301D's transit time frequency <5 MHz and ≥6.0 µs carrier lifetime make it effective down to sub-100 kHz. Its low distortion characteristics are validated in linear attenuator applications from HF through 1 GHz, including AM broadcast band (530–1710 kHz) and LF/MF instrumentation systems where harmonic suppression is critical.

Is RoHS-compliant packaging available for the UM4301D?

No - RoHS-compliant versions of the UM4300 series use the "UMX" prefix (e.g., UMX4301SM for surface-mount). The UM4301D is a legacy stud-mount variant and was not released in a RoHS-compliant version. For RoHS requirements, consider evaluating UMX4301SM with appropriate thermal derating and layout adaptation.