The AD7769 is a complete, two-channel, 8-bit, analog I/O port. It has versatile input and output signal conditioning features that make it ideal for use in head-positioning servos in Winchester disk systems. It is equally suitable for floppy disk microstepping head positioning, other closed loop digital servo systems and general purpose 8-bit data acquisition. The AD7769 contains a high speed successive approximation ADC, preceded by a two-channel multiplexer and signal conditioning circuits. The input span of the ADC and the offset of the zero point from ground can be independently set by applying ground referenced voltages. The AD7769 also contains two independent, fast settling, 8-bit DACs with output amplifiers. The output span and offset voltage of the DACs can be set independently of those of the ADC. This makes the AD7769 especially useful in disk drives, where only a positive supply rail is available and the ranges of the ADC and DACs must be referenced to some positive voltage less than the supply. The AD7769 is easily interfaced to a standard 8-bit mpu bus via an 8-bit data port and standard microprocessor control lines. The AD7769 is fabricated in Linear Compatible CMOS (LC2MOS), an advanced, mixed technology process that combines precision bipolar circuits with low power CMOS logic. The part is available in a 28-lead plastic DIP and 28-terminal PLCC package.