ANALOG DEVICES (ADI) debuted its series of highly integrated RF/intermediate-frequency (IF) variable gain amplifiers (VGAs) at EuMW. The ADL5201, ADL5202, ADL5240, and ADL5243 amplifiers combine as many as four discrete RF/ IF blocks into a single device. With this level of integration, radio system manufacturers can reduce component count. The ADL5201 and its dual-amplifier version, the ADL5202, are digitally controlled, IF variable-gain amplifiers. They are designed to support high IF-sampling receiver designs for new broadband-radio designs, which require precise gain control, high third-order intercept performance, and a low noise figure. By incorporating proprietary distortion-cancellation techniques, for example, they can achieve output third-order intercept performance of +47 dBm with a noise figure of 6 dB. The VGAs combine high dynamic range with low distortion and noise figures for intermediate frequencies to 400 MHz.

Operating in the 100-to-4000-MHz frequency range, the ADL5240 and ADL5243 RF/IF digitally controlled VGAs offer impressive gain control performance and accuracy. Designed with gallium-arsenide (GaAs) technology, the ADL5240 VGA incorporates a digital step attenuator (DSA) and a gain block into a single integrated circuit. In contrast, the ADL5243 combines a DSA, gain block, and broadband 0.25-W driver amplifier in a single IC. Either the amplifier or the DSA can be fed first in the signal chain for maximum flexibility.