TI’s versatile high-speed variable gain amplifiers
( 01 Mar 2008 )
Texas Instruments has introduced a family of integrated wideband variable gain amplifiers. The devices’ architecture provides designers with a highly flexible combination of bandwidth, gain and analog input voltage to address design challenges of differential line receivers and equalizers, pulse shaping, continuously variable gain and attenuation stages, automatic gain control (AGC) and voltage tunable filters. These applications are typically used in the professional video, test and measurement, military, communications and medical markets.
The VCA820, VCA821, VCA822 and VCA824 offer industry-leading bandwidth, noise and slew rate with a flexible analog input voltage. These features enable customers to process large amounts of data at faster rates while minimizing harmonic distortion to improve signal fidelity. The VCA821 and VCA824 offer the industry’s largest bandwidth of 420 MHz for a gain of 10 V/V which is over 300 percent larger than comparable devices. They also provide the fastest slew rate of 2500 V/µs, which is 40 percent faster than what is available today. The VCA820 and VCA822, meanwhile, offer a competitive 150 MHz bandwidth and slew rate of 1700 V/µs.
The VCA82x voltage-controlled amplifiers give customers the ability to set the maximum gain anywhere from 0 dB (1 V/V) to 40 dB (100 V/V) with external resistors. An externally supplied gain voltage can then be varied dynamically to implement a greater than 40 dB gain adjust range. Designers can also choose between linear gain in dB/V or V/V.
