SAR ADC Achieves 99.8 dB SNR

Achieving 99.8 dB signal-to-noise ratio (SNR) and -116 dB total harmonic distortion (THD) at sample rates up to 2.5 Msamples/s, Linear Technology’s 18-bit no cycle latency SAR analog-to-digital converter (ADC) is claimed as the fastest to date in its class. Operating from a single 5V supply, the LTC2389-18 supports three pin-configurable analog input ranges. For its highest SNR performance, the converter can be configured for fully differential (±4.096 V) inputs. The pseudo-differential unipolar (0 V to 4.096 V) and bipolar (±2.048 V) analog input ranges enable lower power single-ended drive. Suited for demanding designs requiring maximum signal swings at low power levels in noisy industrial environments, the converter features ±3 LSB INL (max), ±10 LSB offset error and 18 bits no missing codes resolution. It dissipates 162.5 mW at 2.5 Msamples/s with a shutdown mode that reduces power dissipation to 75 µW when not converting. The LTC2389-18 provides a flexible digital interface supporting 2.5 Msamples/s throughput with parallel interface and 1.9 Msamples/s throughput with serial SPI interface at I/O voltages from 1.8V to 5V. Available in 48-pin 7 mm x 7 mm LQFP and QFN packages, the LTC2389-18 is priced at $33.90 each/1,000.

LINEAR TECHNOLOGY CORP.