Precision isolation amplifier composed of ISO120/ISO121

ISO120/121 is a precision isolation amplifier with a novel duty cycle modulation-demodulation technology. When sending signals, the digital signal passes through a 2pF differential capacitance isolation barrier. The isolation barrier with digital modulation characteristics does not affect the integrity of the signal, so it has excellent reliability and high-frequency transient suppression characteristics. The amplifier and the gate capacitor are sealed together in the DIP. The difference between ISO120 and ISO121 is only in the package size and the rated isolation voltage. These amplifiers are easy to use and can obtain a bandwidth of 60kHz without external components. If two external capacitors are used, a precision rated nonlinearity of 0.01% (maximum) and a Vos drift of 150μV/℃ (maximum) within a 6kHz bandwidth can be guaranteed. The power supply range of ISO120/121 is ±4.5~±18V, with low quiescent current. Its pin arrangement is shown in the figure, where the first pin number is ISO120 and the second pin number is ISO121.

Internal equivalent circuit: