A precise temperature-insensitive and linear-in-dB variable gain amplifier

A fully temperature-compensated linear-in-dB variable gain amplifier (VGA) is presented. The VGA achieves wide dynamic range and precise linear-in-dB control capability using a translinear current amplifier. The compensation technique having current proportional to the squared temperature is proposed. The VGA is implemented with 0.35 /spl mu/m SiGe BiCMOS process. Greater than 90 dB dynamic range while having only /spl plusmn/3 dB gain drift from -30/spl deg/C to 85/spl deg/C temperature range is measured.

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