A pair of quad and dual-channel, digital variable gain amplifiers (DVGA) that enable higher-performance wideband radio ­systems have been developed by National Semiconductor. The DVGAs provide good ­linearity performance over a wide frequency range, making them ideal for multi-channel wideband wireless systems.

Target applications include intermediate frequency (IF) ­sampling receivers, I/Q digital pre-distortion (DPD) signal paths and wide-bandwidth direct-conversion radios used in multi-carrier GSM, TD-SCDMA, W-CDMA and LTE wireless basestations.

This benefits radio designers who are aiming to produce cost effective anti-alias filters (AAF) that meet the requirements of today’s wider radio bandwidths.

Being able to select from a range of filter impedance levels, including low impedance levels such as 50-Ohms, simplifies the AAF design and improves performance and manufacturability.

The DVGAs drive a wide range of load impedances. Their low-Z output drive supports signal fidelity and provides the additional power gain needed when driving low impedance filters.