The AD7874 is a four-channel simultaneous sampling, 12-bit data acquisition system. The part contains a high speed 12-bit ADC, on-chip reference, on-chip clock and four track/hold amplifiers. This latter feature allows the four input channels to be sampled simultaneously, thus preserving the relative phase information of the four input channels, which is not possible if all four channels share a single track/hold amplifier. This makes the AD7874 ideal for applications such as phased-array sonar and ac motor controllers where the relative phase information is important.