HMC985A

Overview

The HMC985A is an absorptive GaAs MMIC Voltage Variable Attenuator (VVA) designed for high-frequency applications. It operates within a frequency range of 20 GHz to 50 GHz, providing a dynamic attenuation range exceeding 37 dB. The device features a maximum attenuation of 42 dB and an insertion loss of 2.9 dB. It maintains a standard impedance of 50 Ohms across a single channel. The component supports SMD/SMT installation in an SMT-24 package or die form. It functions on a DC control signal with a supply voltage ranging from -5 V to 0 V. The operational temperature range extends from -40 C to +85 C.

Feature Summary

• Absorptive design ensures stable impedance matching across the operating bandwidth
• Analog DC control signal enables precise adjustment of RF signal levels
• GaAs MMIC technology supports operation up to 50 GHz

Applications

• RF signal level control in microwave systems
• Phased array antenna beamforming networks
• Test and measurement instrumentation requiring variable attenuation

Procurement Notes

Verify the specific suffix designation when ordering, as availability varies between die and packaged forms. Confirm that the required frequency range aligns with the 20-50 GHz specification rather than broader ranges cited in some general descriptions. Ensure the control interface matches the analog DC voltage requirements specified in the official datasheet.

Selection Notes

Select this component when analog control of high-frequency signals is required without reflection issues due to its absorptive nature. Consider the thermal management capabilities given the operating temperature limits. Verify that the 50 Ohm impedance matches the system requirements. Evaluate the need for GaAs MMIC performance over other technologies at these frequencies.

Part Context

The HMC985A belongs to Analog Devices' family of GaAs MMIC voltage variable attenuators. It is engineered for applications demanding wide bandwidth and high linearity in the K-band and above. The part is available in different physical configurations, including die and surface mount packages, catering to diverse integration needs in wireless infrastructure and defense electronics.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material. Users should consult Analog Devices for current alternatives if this specific model is discontinued or unavailable.