Digitally controllable variable-gain amplifiers in 0.18-μm CMOS technology for μ-power applications

Two μ-power VGA circuits targeting the body sensor network applications are designed in 0.18-μm CMOS technology. By employing a digitally switched-load gain variation scheme, the gain of the first VGA and the second VGA can be varied linearly from -18.5 dB to +24.5 dB, and from +16 dB to +54 dB, respectively. Input-referred noise at maximum gain mode is less than 17 nV/radicHz and the current consumption is less than 400 μA from a 1.8 V supply for both circuits. The VGAs exhibit excellent linearity in terms of gain variation and gain compression. Small silicon area is achieved by avoiding bulky passive components.