SAR ADC offers a new and enabling approach for precision measurement applications

Linear Technology has announced the LTC2500-32, an ultra-high precision 32-bit SAR ADC. The device is a new and enabling approach for precision measurement applications, blending the high accuracy and speed of the company’s proprietary SAR ADC architecture with flexible integrated digital filters to optimize system signal bandwidth and ease analog anti-aliasing filter requirements. The device simultaneously provides two outputs: (1) a 32-bit low noise digitally filtered output that achieves up to 148dB of dynamic range and (2) a 32-bit 1Msps no latency output comprising an over-range detection bit, a 24-bit representation of the input voltage difference, and a 7-bit representation of the common mode input voltage. The no latency output is inherently perfectly matched to the digitally filtered output, avoiding the mismatch and drift that typically occur in applications requiring an additional faster ADC to monitor signal integrity in parallel with a precision ADC. The wide input common mode range and high CMRR enable the device to interface signals with varying common mode, simplifying the analog signal chain. Each of the two outputs provides a highly accurate representation of the voltage difference applied between the two input terminals. The exceptional low noise density of the device produces 148dB of dynamic range at 61sps and 104dB at 1Msps. In addition to low noise, it offers unrivalled linearity of 0.5ppm typical and 2ppm guaranteed maximum INL, and negligibly low gain and offset drift over wide temperature ranges. In combination, these features enable state-of-the-art high precision measurements in noisy environments, such as in industrial automation applications. The integrated configurable digital filter offers seven filter types and 13 different downsampling factors, providing users with a high level of flexibility to trade off bandwidth, filter response and noise performance for each application.