LTC2369 Series SAR ADCs

By Analog Devices Inc 237

LTC2369 Series SAR ADCs

Linear Technology introduces the LTC2369-18, a serial 18-bit, 1.6 MSPS pseudo-differential SAR analog-to-digital converter (ADC), which achieves impressive 96.5 dB SNR and -120 dB THD while supporting a 0 V to 5 V unipolar input range. The pseudo-differential input simplifies the ADC driver requirement, enabling single-ended drive while benefiting from the reduction of unwanted signals common to both inputs. This reduces complexity and lowers the power requirements in the signal chain. Operating from a 2.5 V supply, the LTC2369-18 consumes only 18 mW, with a low power shutdown mode that consumes just 2.25 µW. When used in combination with the recommended single-ended ADC driver LT6202, the combined power dissipation is a mere 53 mW, a 40% reduction from a fully differential drive circuit. The LTC2369-18 is the industry's highest performing 18-bit pseudo-differential SAR ADC, featuring a maximum INL of ±2.5 LSB with no missing codes and guaranteed specifications over the -40°C to +125°C temperature range.

Complementing the LTC2369-18 is the pin- and software-compatible 16-bit, 2 MSPS LTC2369-16. The LTC2369-16 achieves outstanding 94 dB SNR and ±0.85 LSB maximum INL. The LTC2369-18 and LTC2369-16 are the first in a family of 18-/16-bit high performance pseudo-differential SAR ADCs with speeds ranging from 250 kSPS to 2 MSPS . They offer a user-friendly SPI interface, explicit busy and chain pins, I/O voltages from 1.8 V to 5 V and an internal oscillator that simplifies digital timing and minimizes external component count. Their true no-latency operation enables accurate one-shot measurements even after lengthy idle periods with no minimum sample rate required.

Features
  • 1.6 MSPS throughput rate
  • ±2.5 LSB INL (max.)
  • Guaranteed 18-bit no missing codes
  • Low power: 18 mW at 1.6 MSPS, 18 µW at 1.6 kSPS
  • 96.5dB SNR (typ.) at fIN = 2 kHz
  • -120dB THD (typ.) at fIN = 2 kHz
  • Guaranteed operation to 125°C
  • 2.5 V supply
  • Pseudo-differential unipolar input range: 0 V to VREF
  • VREF input range from 2.5 V to 5.1 V
  • No pipeline delay, no cycle latency
  • 1.8 V to 5 V I/O voltages
  • SPI-compatible serial I/O with daisy-chain mode
  • Internal conversion clock
  • 16-lead MSOP and 4 mm x 3 mm DFN packages

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