The 8-channel, multiplexed, successive approximation register (SAR) ADCs provide reliable performance for applications, such as rack servers, AC drive power stage modules, automotive centre information displays, and mobile robot CPU boards.
The ADS7028 and ADS7138 ADCs feature eight channels that can be configured in any combination of analogue inputs, digital inputs, or digital outputs. The devices feature an internal oscillator for ADC processes, as well as a built-in cyclical redundancy check for power-up configuration and data read/write operations. Both ADCs feature open-drain, push-pull digital outputs for I/O expansion, while the devices’ analogue watchdog function includes an event counter for transient rejection and programmable thresholds for each channel. The ADCs feature wide operating ranges of 2.35V to 5.5V AVDD and 1.65V to 5.5V DVDD.
The ADS7028 communicates through an SPI-compatible interface with a sampling frequency of 1 MSPS, while the ADS7138 communicates using an I²C-compatible interface capable of operating at a frequency of up to 3.4 MHz. Both ADCs operate in either autonomous or single-shot conversion mode.
The ADS7028 ADC also offers a root-mean-square module that computes a 16-bit true RMS output for any analogue input, as well as a zero-crossing-detect module that features built-in transient rejection and hysteresis near configurable threshold crossings.