A digital attenuator, unlike variable attenuators, switches in discrete and finite attenuation states. This switching is usually achieved in binary steps. Digital attenuators employ semiconductor devices to achieve each attenuation step. Some of the semiconductor devices employed for this purpose include: PIN diodes, MOSFETs, and GaAs MESFET. These devices are capable of achieving switching rates that are comparable to the speeds of solid-state switches. The most common types of logic used by digital attenuators are CMOS logic levels and transistor-transistor logic (TTL).

Digital attenuators utilize driver circuitry to determine the type of logic to be used. The complexity of driver circuitry depends on the number of bits used. Complexity increases with the number of bits. It is common to classify digital attenuators according to the attenuation states that they are designed to offer. The number of bits used determines these attenuation states. The most-significant bit provides the largest attenuation while the least-significant bit provides the smallest attenuation that a component offers. The remaining bits supply intermediate attenuation values.

Digital attenuators are designed to give maximum rated attenuation if all the bits are selected. On the other hand, its minimum attenuation step is achieved by selecting the least significant bit only. Digital attenuators have wide uses in 3G and 4G cellular networks, point-to-point nodes, repeaters, and in a wide selection of test and measurement applications.