Approach to high-linear programmable gain amplifiers

Two different approaches to digitally programmable gain amplifiers (PGAs) are presented in this paper and compared in terms of linearity, frequency, area and power consumption. They are characterized by their inherently high linearity and wide gain tuning. In the first proposal, linearity is achieved by using poly resistor arrays whereas the second is based on a MOST-only inherently linear current division principle. The paper presents the principles of operation and design equations of both approaches, in addition to experimental results in a 2.5 V 0.35 /spl mu/m CMOS process which show their trade-offs.