SBAS894A April 2018 – October 2018 ADS112C04
The ADS112C04 is a small, low-power, 16-bit, ΔΣ ADC that offers many integrated features to reduce system cost and component count in applications measuring small sensor signals.
In addition to the ΔΣ ADC core and single-cycle settling digital filter, the device offers a low-noise, high input impedance, programmable gain amplifier (PGA), an internal 2.048-V voltage reference, and a clock oscillator. The device also integrates a highly linear and accurate temperature sensor as well as two matched programmable current sources (IDACs) for sensor excitation. All of these features are intended to reduce the required external circuitry in typical sensor applications and improve overall system performance. The device is fully configured through four registers and controlled by six commands through an I2C-compatible interface. The Functional Block Diagram section shows the device functional block diagram.
The ADS112C04 ADC measures a differential signal, VIN, which is the difference in voltage between nodes AINP and AINN. The converter core consists of a differential, switched-capacitor, ΔΣ modulator followed by a digital filter. The digital filter receives a high-speed bitstream from the modulator and outputs a code proportional to the input voltage. This architecture results in a very strong attenuation of any common-mode signal.
The device has two available conversion modes: single-shot conversion and continuous conversion mode. In single-shot conversion mode, the ADC performs one conversion of the input signal upon request and stores the value in an internal data buffer. The device then enters a low-power state to save power. Single-shot conversion mode is intended to provide significant power savings in systems that require only periodic conversions, or when there are long idle periods between conversions. In continuous conversion mode, the ADC automatically begins a conversion of the input signal as soon as the previous conversion is completed. New data are available at the programmed data rate. Data can be read at any time without concern of data corruption and always reflect the most recently completed conversion.