Cell-based variable-gain amplifiers with accurate dB-linear characteristic in 0.18 mu m CMOS technology

Hang Liu, Xi Zhu, Chirn Chye Boon, Xiaofeng He

    Research output: Contribution to journalArticlepeer-review

    74 Citations (Scopus)


    A simple and robust "cell-based" method is presented for the design of variable-gain amplifiers (VGAs). The proposed unit cell utilizes a unique gain compensation method and achieves accurate dB-linear characteristic across a wide tuning range with low power consumption and wide bandwidth. Several such highly dB-linear unit cells can be cascaded to provide the required gain range for a VGA. To prove the concept, single-cell, 5-cell, 10-cell and 15-cell reconfigurable VGAs were fabricated in a standard 0.18 μm CMOS technology. The measurement results show that the 10-cell VGA achieves a gain range of 38.6 dB with less than 0.19 dB gain error. The 15-cell VGA can either be used as reconfigurable VGA for analog control voltage or tunable PGA for digital control stream, with the flexibility of scaling gain range, gain error/step and power consumption. For the VGA at highest gain setting, it consumes 1.12 mW and achieves a gain range of 56 dB, gain error less than 0.3 dB.

    Original languageEnglish
    Article number6975257
    Pages (from-to)586-596
    Number of pages11
    JournalIEEE Journal of Solid-State Circuits
    Issue number2
    Publication statusPublished - 1 Feb 2015


    • Cell based
    • CMOS variable gain amplifier
    • dB-linear
    • gain compensation
    • low power
    • power scalable
    • programmable gain amplifier
    • reconfigurable


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