The HMC624A is a 6-bit digital attenuator with a 31.5 dB attenuation control range in 0.5 dB steps. The HMC624A offers excellent attenuation accuracy and high input linearity over the specified frequency range from 100 MHz to 6.0 GHz. However， this digital attenuator features external ac grounding capacitors to extend the operation below 100 MHz. The HMC624A is integrated with two dies： a CMOS driver and a gallium arsenide （GaAs） RF attenuator. The CMOS driver provides both serial and parallel control of the RF attenuator. The device also features a user-selectable power-up state and a serial output port for cascading other serial controlled components. The HMC624A operates with a single positive supply voltage from 3 V to 5 V， and provides a CMOS-/TTL-compatible control interface. The HMC624A comes in a RoHS compliant， compact， 4 mm × 4 mm LFCSP package， and is pin compatible to the HMC1122 except for the ACGx pins.