Accurate dB-Linear Variable Gain Amplifier With Gain Error Compensation

作者：Choi Inyoung^*; Seo Heesong; Kim Bumman

来源：IEEE Journal of Solid-State Circuits, 2013, 48(2): 456-464.

DOI：10.1109/JSSC.2012.2227606

• Baseband amplifier
• dB-linear
• exponential approximation
• gain error compensation
• linear-in-dB
• variable gain amplifier (VGA)

This paper describes use of a novel exponential approximation for designing dB-linear variable gain amplifiers (VGAs). The exponential function is accurately generated using a simple error-compensation technique. The dB-linear gain is controlled linearly by the gate voltage, resulting in a simple and robust VGA. The proposed dB-linear VGA fabricated in a 65-nm CMOS process achieves a total variable gain range of 76 dB and dB-linear range greater than 50 dB with +/- 0.5-dB gain error. Under a 1.2-V supply voltage, the current consumption of the VGA is 1.8 mA and that of the output buffer is 1.4 mA. The input-referred in-band noise density is 3.5 nV/root Hz and the in-band OIP3 is 11.5 dBm. Due to the very simple circuit topology, the total active area of the VGA and the output buffer is extremely small, 0.01 mm(2).

• 出版日期2013-2