ISO164 and ISO174 are PGA input isolation amplifiers incorporating a novel duty cycle modulation-demodulation technique which provides excellent accuracy. Internal input protection can withstand up to ±40V differential inputs without damage. The signal is transmitted digitally across a differential capacitive barrier. With digital modulation the barrier characteristics do not affect signal integrity. This results in excellent reliability and good high frequency transient immunity across the barrier. Both the amplifier and barrier capacitors are housed in a plastic DIP. ISO164 and ISO174 differ in frequency response and linearity. These amplifiers are easy to use. No external components are required. A power supply range of ±4.5V to ±18V makes these amplifiers ideal for a wide range of applications.