The HMC881A is a monolithic microwave integrated circuit (MMIC) low-pass filter that features a user-selectable cutoff frequency. The cutoff frequency can be varied from 2.4 GHz to 4 GHz by applying a single analog tuning voltage between 0 V and 14 V. This low-pass filter provides a low 3 dB insertion loss, 16.5 dB return loss, and 1.35 × f_3dB stopband attenuation of >20 dB. This tunable filter can be used as a much smaller alternative to physically large switched filter banks and cavity tuned filters. The HMC881A has excellent microphonics due to the monolithic design, and provides a dynamically adjustable solution in advanced communications applications. The low-pass tunable filter is packaged in a RoHS compliant 5 mm × 5 mm LFCSP package.