Microchip Technology UM4001CR

Overview

UM4001CR from Microsemi is a high-power RF PIN diode designed for low-distortion switching and attenuation in HF–S-band systems. It features 200 V reverse voltage rating, 0.5 Ω typical series resistance at 100 MHz, >5 µs carrier lifetime, 3 pF capacitance at 100 V/1 MHz, and operates in stud-mounted isolated packages for thermal reliability in phase shifters and duplexers.

For engineers reviewing the UM4001CR datasheet, UM4001CR pinout, UM4001CR application, or UM4001CR equivalent, key selection criteria include reverse voltage margin, RF series resistance at operating frequency, carrier lifetime impact on switching linearity, thermal path configuration (stud vs. surface mount), and compatibility with high-peak-power pulsed RF environments.

Technical Context

The UM4001CR uses a non-cavity, thick I-region PIN structure optimized for high RF power handling and low intermodulation distortion. Its long carrier lifetime (>5 µs) enables efficient control of high RF signal levels with modest DC bias current, while low 0 V-bias capacitance (≤3 pF) and conductance support broadband impedance matching in filter and cavity networks.

Thermally, the CR package employs an isolated stud-mount configuration with direct chip-to-stud thermal conduction-enabling 25 W power dissipation at 25°C stud temperature and 12 W in free air. This architecture supports proven operation in megawatt-peak-power UHF duplexers and high-reliability antenna selector designs.

Key Specifications

Pinout & Package

The UM4001CR is housed in an isolated stud-mount "CR" package (Style CR per Microsemi mechanical drawings), featuring a metal stud anode terminal and insulated cathode flange for high-voltage standoff and direct heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UM4001CR, UMX4001CR offers identical RF and thermal behavior with lead-free process compatibility, while UM4901CR delivers superior steady-state thermal capacity at the cost of slightly higher package inductance-making UM4001CR optimal for pulsed, medium-average-power S-band switches where cost and legacy process alignment matter.

Availability

UM4001CR is available at Aetrix Electronics and suitable for UHF phase shifters, radar duplexers, antenna selection networks, and RF filter tuning arrays requiring stable component supply across extended production lifecycles.

Supply support for UM4001CR 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) specializes in high-reliability analog and RF semiconductors for aerospace, defense, and communications infrastructure.

The UM4000/UM4900 series was engineered specifically for high-power microwave switching in mission-critical radar, EW, and SATCOM systems where RF linearity, thermal robustness, and long-term reliability are non-negotiable.

FAQ

What is the maximum reverse voltage rating for UM4001CR?

The UM4001CR has a reverse voltage rating of 200 V at 10 µA leakage current. This rating defines the maximum DC or peak RF voltage the device can block in its off state without breakdown. Exceeding this voltage risks irreversible avalanche damage, especially under high-duty-cycle or high-temperature conditions. The 200 V rating makes UM4001CR suitable for S-band radar switches and UHF antenna tuners where peak RF voltages remain below this threshold.

How does UM4001CR's carrier lifetime affect RF linearity?

UM4001CR's carrier lifetime exceeds 5 µs, which directly improves RF linearity by reducing harmonic and intermodulation distortion during high-level signal switching. Longer lifetime allows smoother charge storage modulation under RF drive, enabling clean switching transitions even at +40 dBm input power. This characteristic is critical in phase shifters and attenuators where third-order intercept point (IP3) must exceed +60 dBm-achievable only with lifetime-optimized PIN diodes like UM4001CR.

Can UM4001CR be used in surface-mount designs?

No-UM4001CR is exclusively offered in the CR-style isolated stud-mount package, not a surface-mount variant. The CR package requires mechanical fastening to a heatsink via its threaded anode stud and relies on direct thermal conduction through the stud. For surface-mount alternatives, consider the SM-package variants (e.g., UM4001SM), which share the same 200 V rating and electrical specs but use a different thermal and mechanical interface incompatible with UM4001CR's mounting requirements.

What is the typical series resistance of UM4001CR at 100 MHz?

The typical series resistance (R_S) of UM4001CR is 0.5 Ω when measured at 100 MHz with 100 mA forward bias. This value determines insertion loss in the on-state and power dissipation under RF current flow. At higher frequencies (e.g., 2 GHz), R_S increases slightly due to skin effect, but remains below 0.7 Ω-ensuring low-loss performance in S-band switch designs. Designers use this spec to calculate worst-case I²R heating and verify thermal margin in high-duty-cycle operation.

Is UM4001CR RoHS compliant?

The standard UM4001CR uses Sn/Pb plating and is not RoHS compliant. However, Microsemi offers the functionally identical UMX4001CR variant with matte tin finish that meets EU Directive 2002/95/EC. Both parts share identical electrical, thermal, and mechanical specifications-the only difference is the termination finish. Customers requiring RoHS compliance must specify UMX4001CR; substituting UM4001CR in lead-free assembly processes may cause solder joint reliability issues.