Linear Technology's 16-bit, 20-Msps ADCs achieve 84-dB SNR and 46-?VRMS RTI noise



Click image to enlarge: low noise 16-bit 20-Msps ADCs dissipate only 80 mW/ch; 12 mW in standby and 0.5 mW in shutdown.

Linear Technology has introduced three low-power 16-bit, 20-Msps ADCs, the LTC2269, LTC2270, and LTC2271 offering the low input-referred noise and tight INL (integral nonlinearity error) for high-precision DC measurements. With only 46-μVRMS input noise and maximum guaranteed INL error of ±2.3 LSB, these ADCs are suitable for low-noise, high-linearity sampling applications such as digital x-ray, infrared and medical imaging, pachymeters, spectrometry, and cytometry. These devices achieve SNR (signal-to-noise ratio) performance of 84 dB and SFDR (spurious-free dynamic range) of 99 dB at baseband. The ADCs achieve high AC performance and low noise using a well-designed 2.1 Vp-p front end, which also significantly lowers the power required by the ADC driver circuitry. The ADCs themselves consume approximately 80 mW/channel. Product designs can achieve further power savings by placing the devices in standby (12 mW) or shutdown (0.5 mW), making them well suited for handheld test-and-measurement applications. The LTC2269 and LTC2270 are single-channel and two-channel simultaneous sampling parallel ADCs, respectively, offering a choice of full-rate CMOS, or DDR (double data rate) CMOS/LVDS digital outputs with programmable digital output timing, programmable LVDS output current, and optional LVDS output termination. The LTC2271 includes two-channel, simultaneous sampling ADCs with serial LVDS outputs. They include Linear Technology's digital output randomizer and ABP (alternate bit polarity) mode that minimize digital feedback in the application. These low-power 16-bit ADCs provide a pin-compatible upgrade to the existing LTC2160, LTC2180, and LTC2190 families of 25-Msps to 125-Msps 1.8-V low-power ADCs. Available in compact QFN packages, designers can benefit from the flexible choice of interfaces to minimize pin count and ease routing to FPGAs. Summary of Features: LTC2270

  • 16-bit, 20-Msps single and dual ADCs
  • 84 dB SNR, 99 dB SFDR
  • 46 μVRMS input-referred noise
  • ±2.3-LSB INL error (max)
  • Low power: 80 mW/Ch
  • Single 1.8-V Supply
  • Flexible digital interfaces:
    • CMOS, DDR CMOS or DDR LVDS Outputs
    • Serial LVDS
  • Selectable input ranges: 1 VP-P to 2.1 VP-P
  • 200-MHz full-power bandwidth S/H
  • Optional data output randomizer
  • Optional clock duty-cycle stabilizer
  • Shutdown & nap modes
  • Serial SPI port for configuration
These ADCs are now in production, with evaluation boards and samples available online or from your local Linear Technology sales office. Pricing starts at $30.00 each for the single LTC2269 device in 1,000-piece quantities. Linear Technology Product deeplink