RF ICs reduce component count, board space in broadband comms applications
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Analog Devices has announced two variable gain amplifiers that incorporate 'unprecedented' levels of integration for designers of broadband communications systems.
The ADRF6516 VGA features dual channel, programmable, 6pole low pass filers and VGAs in a single chip, while the ADL5336 VGA integrates two intermediate frequency VGAs and pair of programmable root mean square (rms) detectors.
The ADRF6516 is a single chip, matched pair of variable gain amplifiers with programmable low pass filters suitable for baseband a/d converter driver applications. The 65dB amplifier gain control range is split between a 15dB digital VGA input stage and a 50dB analogue VGA output stage. By using SPI control the corner frequency of the 31MHz, 6pole Butterworth filter can be selected in 1MHz resolution. According to ADI, the integration of the programmable filter reduces the board space and discrete components required to implement a discrete filter. The flexibility in gain setting and filter programming allows the device to support a receiver with a variable signal bandwidth and gain requirements.
The integrated ADL5336 is a cascadable analogue dual IF VGA with two integrated rms detectors which have been designed to replace up to four discrete rf components - plus additional passive discrete components. The device can operate independently or as two cascaded amplifiers, while the rms detectors can be programmed for independent gain control for each VGA. When the ADL5336 is configured in a cascaded VGA mode, it provides a continuous gain control range of 48dB. Individually, each VGA provides a gain control range of 24dB and the maximum gain for each amplifier can be programmed via SPI control.
The setpoint for each integrated detector is also programmed via the SPI in 3dB steps. An additional switch has been integrated to allow the second VGA to toggle between two input sources. The ADL5336's linearity and noise figure performance allows the device to be used in applications requiring high dynamic range such as point to multipoint radios and instrumentation and medical equipment.
Peter Real, ADI's vice president, Linear and RF products, pictured, said: "Whether they are addressing point to point microwave radios, wireless base stations, communications test equipment or other applications, rf system designers can take advantage of the high level of integration and still achieve breakthrough levels of performance when compared to traditional discrete rf designs."
