MOS current divider based PGA

A highly linear, digitally programmable gain amplifier (PGA) based on an inherently linear MOS current divider (MCD) is presented in this paper. A 3-bit prototype with a total variation range of 36 dB in gain has been implemented in a 3.3 V-0.35 μm CMOS process with 2.5 V supply voltage. Experimental results prove the high linearity of the system, which presents distortion levels better than −70 dB for 1 MHz and 1 Vp-p output signals.