Wideband, 18-bit SAR ADC betters pipelined-converter SNR

October 01, 2015 // By Graham Prophet
LTC2387-18 is an ultrafast 15 Msample/sec, 18-bit successive approximation register (SAR) analogue-to-digital converter (ADC) with no cycle latency and no pipeline delay. Applications that have used fast throughput pipelined ADCs can see 20dB signal-to-noise ratio (SNR) improvement.

The ADC digitises wideband analogue signals up to the Nyquist frequency with very low distortion. Applications include communications, high speed imaging and instrumentation. LTC2387-18 achieves an SNR of 95.7 dB and realises -101 dB total harmonic distortion (THD) while digitising a 1 MHz analogue input signal. The high SNR and low distortion performance, combined with fast digitising throughput, enable the ADC to measure very low signal levels with greater precision and accuracy, improving image contrast and definition in high end imaging applications. The no-latency operation enables use in data acquisition systems that require fast control loops. To limit noise introduced from the digital outputs, the sampled data of this ADC is communicated via single- or dual-lane serial LVDS outputs to the host processor, providing good noise immunity for noise-sensitive applications.

LTC2387-18 is the lead product in a pin-compatible family of 18- and 16-bit SAR ADCs with sampling rates ranging from 5 to 15 Msamples/sec. It comes in a 32-lead 5 x 5 mm plastic QFN package, specified over the commercial and industrial temperature ranges, priced starting at $38.95 (1000).

Linear Technology; www.linear.com/product/LTC2387-18

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