Low-power 42 dB-linear single-stage digitally-controlled variable gain amplifier

Abstract

A compact digitally-controlled single-stage variable gain amplifier (VGA) is introduced, which doubles the dB-linear range through the reconfiguration, saves power by 50% while maintaining the same linearity performance compared to those of the previous design. Implemented in 0.18 mm CMOS technology, the 5-bit digitally-controlled VGA achieves dB-linear gain range of 42 dB (221 to 21 dB) with gain error less than +0.55 dB, bandwidth of 84 MHz at maximum gain of 21 dB and maximum IIP3 of 14 dBm while consuming only 760 mA from a 1.8 V supply.

A Binary-Weighted Switching and Reconfiguration-Based Programmable Gain Amplifier

“…In [10], the authors introduced a reconfiguration technique in combination with the binary-weighted switching technique that doubles the gain range of the single-stage PGA while saving on power consumption by half and maintaining nearly the same chip size and gain error compared with those of the PGA cell reported in [9]. Fig.…”

“…5), the PGA gain becomes process and temperature independent. Compared with the binary-weighted transistor array-based PGA reported in [9] or a PGA based on complementary transistor arrays using the reconfiguration technique [10], the newly proposed all-NMOS transistor array-based reconfigurable PGA offers performance advantages in terms of gain range, chip size, process/temperature independence, and low voltage operation. However, due to the additional parasitic capacitance of switches, which are used to change the roles of the arrays 1 and 2, at the output nodes, the proposed PGA shown in Fig.…”

“…In Section II of this brief, the binary-weighted switching technique is analyzed in more detail. In [10], by adopting the binary-weighted switching and reconfiguration techniques, the authors have reported on a PGA that extends the dB-linear range while saving on power consumption and chip size. In Section III, the reconfiguration technique is discussed.…”

“…In Section III, the reconfiguration technique is discussed. In Section IV, adopting the two techniques, a new low-voltage PGA is proposed, which offers a precise process/temperature-insensitive gain characteristic and doubles the dB-linear range of [9], with a small gain error while maintaining the same chip size as in [9] and [10]. Section V presents the measurement results of the proposed PGA, and conclusions are given in Section VI.…”

A versatile technique for linearly tunable transconductors

“…Tunable transconductors are important building blocks employed in many analog circuit applications as in high frequency amplifiers [1], continuous-time filters [2,3] and variable gain amplifiers [4][5][6][7]. Transconductance adjustment is necessary for programming circuit/system parameters, like center frequency and quality factor of filters, for setting the voltage gain of amplifiers or for compensating the tolerances due to process and temperature variations [8][9][10].…”