Description

The AD7938-6 is a 12-bit, high speed, low power, successive approximation (SAR) analog-to-digital converter (ADC). The part operates from a single 2.7 V to 5.25 V power supply and features throughput rates up to 625 kSPS. The part contains a low noise, wide bandwidth, differential track-and-hold amplifier that can handle input frequencies up to 50 MHz.The AD7938-6 features eight analog input channels with a channel sequencer that allows a preprogrammed selection of channels to be converted sequentially. The part can operatewith either single-ended, fully differential, or pseudo differential analog inputs.The conversion process and data acquisition are controlled using standard control inputs that allow easy interfacing with microprocessors and DSPs. The input signal is sampled on the falling edge of CONVST and the conversion is initiated at this point.The AD7938-6 has an accurate on-chip 2.5 V reference that can be used as the reference source for the analog-to-digital conversion. Alternatively, this pin can be overdriven to provide an external reference.The AD7938-6 uses advanced design techniques to achieve very low power dissipation at high throughput rates. The part also features flexible power management options. An on-chip control register allows the user to set up different operating conditions, including analog input range and configuration, output coding, power management, and channel sequencing.PRODUCT HIGHLIGHTS High throughput with low power consumption. Eight analog inputs with a channel sequencer. Accurate on-chip 2.5 V reference. Single-ended, pseudo differential, or fully differential analog inputs that are software selectable. Single-supply operation with VDRIVE function. The VDRIVE function allows the parallel interface to connect directly to 3 V or 5 V processor systems independent of VDD. No pipeline delay. Accurate control of the sampling instant via a CONVST input and once-off conversion control.