Qorvo CMD325

Overview

The CMD325 from Qorvo is a GaAs MMIC 6-bit digital attenuator die operating from DC to 30 GHz, with negative voltage control (0 V / −5 V), 31.5 dB total attenuation (0.5–16 dB bit steps), 4 dB insertion loss at 12 GHz, and 50 Ω RF port matching for direct integration into microwave front-ends used in test instrumentation and phased array radar.

For engineers reviewing the CMD325 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, die-level package details, truth-table–driven control logic, thermal and ESD handling guidance, and validated alternatives for high-frequency RF system design.

Technical Context

The CMD325 implements a monolithic GaAs-based switched-resistor attenuator architecture with six independent bit-control lines (P0–P5) and a common −5 V bias (Vee). Each bit activates a dedicated attenuation path with defined step values (0.5, 1, 2, 4, 8, 16 dB), enabling precise, digitally programmable loss states across DC–30 GHz without external matching networks.

It operates under negative control logic: low (0 ±0.3 V) enables a bit, high (−5 ±0.3 V) disables it. The die features full passivation, gold bond pads, and a grounded backside for RF/DC return-requiring conductive epoxy die attach and thermosonic wedge bonding per assembly guidelines.

Key Specifications

Pinout & Package

Package: Bare die, 2300 µm × 1000 µm × 100 µm, fully passivated, gold metallization, grounded backside. Requires conductive epoxy die attach and thermosonic wedge bonding (0.8 mil wire).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wideband digital attenuator applications.

Compared with HMC650LP3E and QPA9807, the CMD325 uniquely offers true DC–30 GHz coverage, negative-voltage control optimized for GaAs bias schemes, and 0.2 dB typical step accuracy-making it the only option for precision, wideband, digitally reconfigurable RF power management in defense and aerospace systems.

Availability

CMD325 is available at Aetrix Electronics and suitable for phased array radar, 5G mmWave test instrumentation, satellite communications uplinks, and electronic warfare systems requiring stable component supply, consistent wafer-lot traceability, and long-term obsolescence mitigation.

Supply support for CMD325 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

Qorvo is a U.S.-based semiconductor company specializing in RF solutions for defense, aerospace, and high-performance wireless infrastructure, with leadership in GaAs, GaN, and BAW technologies.

The CMD325 belongs to Qorvo's high-frequency MMIC attenuator product line, engineered specifically for DC–30 GHz programmable RF power control in mission-critical radar, EW, and satellite communication systems.

FAQ

What is the recommended bias sequence for powering up the CMD325?

Apply Vee (−5 V) to pad 8 before applying any control voltages to P0–P5. This prevents latch-up or damage during startup. The CMD325 will not function unless Vee is present and stable. Control signals (0 V or −5 V) may then be asserted in any order. Always observe ESD precautions-CMD325 is Class 1A HBM sensitive. The CMD325 datasheet specifies absolute maximum ratings including −8 V for Vee and Vctl.

Does the CMD325 require external matching components at its RF ports?

No. The CMD325 is a 50 Ω matched design-its RF1 and RF2 ports are internally matched to 50 Ω across DC–30 GHz, eliminating the need for external baluns, transformers, or stubs. However, DC blocking capacitors are required on both RF ports if the connected circuitry imposes non-zero DC potential. The CMD325's matched architecture reduces layout complexity and improves repeatability in high-frequency assemblies.

What is the meaning of "step error" for the CMD325, and what is its typical value?

Step error is the deviation between the actual attenuation achieved and the ideal sum of enabled bit values (e.g., P0+P1 = 1.5 dB ideal; measured may be 1.52 dB). For the CMD325, typical step error is 0.2 dB across major states (0.5–31.5 dB), with worst-case ±0.6 dB over full frequency and temperature range. This metric directly impacts calibration accuracy in automatic test equipment and phased array beamforming. The CMD325 datasheet reports step error in Section "Electrical Specifications".

Can the CMD325 be operated with positive control voltages instead of negative ones?

No. The CMD325 uses negative control logic: 0 V enables a bit, −5 V disables it. Applying positive voltages (e.g., +3.3 V or +5 V) to P0–P5 exceeds the absolute maximum rating of −8 V for control pins and risks permanent damage. Level-shifting circuitry must convert positive logic outputs to 0 V / −5 V before interfacing with the CMD325. The CMD325 truth table and recommended operating conditions explicitly define this negative-voltage requirement.

What thermal considerations apply when mounting the CMD325 in a high-power application?

The CMD325 has a junction-to-case thermal resistance (θJC) of 131 °C/W. With a max input P1dB of 26 dBm (≈400 mW), even modest RF power levels can raise junction temperature significantly if heatsinking is inadequate. Use electrically conductive, thermally optimized epoxy for die attach, ensure low-thermal-resistance path to the host substrate, and avoid eutectic bonding. The CMD325 operating temperature range is −55 °C to +85 °C, and thermal derating is required above 25 °C ambient.