Voltage-Variable Attenuator Covers 250 To 4000 MHz

DESIGNED AS A GENERAL-PURPOSE block for wireless-infrastructure applications, a new voltage-variable attenuator (VVA) delivers 44 dB of linearly controlled dynamic range from 250 to 4000 MHz. Dubbed the MAX19790, it actually comprises two VVAs integrated in one monolithic integrated circuit (IC). By leveraging a proprietary, silicongermanium (SiGe) BiCMOS process, each attenuator incorporates a patented control circuit to provide a 22-dB attenuation range with a linear control slope of 10 dB/V. Because both attenuators share a common analog control circuit, they can be cascaded together to yield 44 dB total attenuation with a combined linear control slope of 20 dB/V. The attenuators vow to provide superior S21 flatness performance over wide frequency bands and attenuation ranges. When operating over any 125-MHz contiguous band between 950 and 2150 MHz, for example, the MAX19790 delivers typical and maximum flatness levels of 0.13 and 0.89 dB peak-to-peak, respectively, through 30 dB to total attenuation. If even greater S21 flatness is desired, adding a simple equalizer can further improve the circuit's performance. P&A: available now; $5.24 in 1000Q and up, FOB USA.

Maxim Integrated Products, Inc., 120 San Gabriel Dr., Sunnyvale, CA 94086; (408) 737-7600, FAX: (408) 737-7194, Internet: www.maxim-ic.com.

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