Abstract: An ac-coupled differential amplifier having a high common mode rejection ratio (CMRR) and input impedance is disclosed. The ac-coupled amplifier includes a bootstrapped input stage and first and second operational amplifiers, each having a first input, a second input, and an output. The bootstrapped input-stage has a pair of RC high-pass filters, each of which is comprised of a capacitor connected to the first input of each of the operational amplifiers and a pair of resistors connected in series between ground and the first input of each of the operational amplifiers. A pair of bootstrap capacitors connect between each of the series connected resistor pairs of each of the two RC high-pass filters and the second input of each of the operational amplifiers.