PCF8591 is a monolithic, single supply, low-power, 8-bit CMOS data acquisition devices. PCF8591 has 4 analog inputs, one analog output and a serial I2C bus interface. PCF8591 of three address pins A0, A1 and A2 can be used for programming the hardware address, allowing access to eight PCF8591 devices on the same I2C-bus, without the need for additional hardware. Input and output on the PCF8591 device address, control and data signals through two-line bidirectional I2C bus serially transmitted.