Rail-to-rail input and output ADC driver supports high speed 16- to 18-bit SAR ADCs

Linear Technology has introduced a 33 MHz, low noise, rail-to-rail input and output ADC driver that settles to 16-bits in just 350 ns.

The LT6350 is suitable for driving the latest highest performance SAR ADCs such as the LTC2393-16. The LT6350 incorporates two op amps and matched resistors to create a differential output from a single-ended high impedance input. As a result, a differential gain of 2 is achieved with no external feedback resistors, and higher gain can be obtained by using feedback resistors. Each of the two internal op amps achieve a low 1.9 nV/√Hz input-referred noise density, resulting in a total output-referred noise of just 8.2 nV/√Hz. The LT6350 enables high performance ADCs to achieve better than 110 dB SNR over a 1 MHz bandwidth.

The input op amp is trimmed for constant low differential input-referred voltage offset over the input range to prevent VOS steps from degrading distortion. At 100 kHz, the LT6350 can typically achieve -102/-97dBc HD2/HD3.

The LT6350 provides rail-to-rail input and output range. With a single 5 V supply, the outputs can swing 0.055 V to 4.945 V, and by using a negative supply, the outputs can each swing from 0 V to 4.945 V. The LT6350 operates on 2.7 V to 12 V total supply. The LT6350 consumes 4.8 mA supply current and has a shutdown mode that allows the system to reduce power consumption during periods of inactivity.

Summary of Features: LT6350

  • Rail-to-Rail Input & Outputs
  • Fast Settling Time: 240 ns, 0.01 percent, 8 VP-P Output Step
  • 1.9 nV/√Hz Input-Referred Op Amp Noise
  • High Impedance Input
  • No External Gain-Resistors Required
  • 2.7 V to 12 V Supply Operation, 4.8 mA Supply Current
  • Low Power Shutdown
  • Low Distortion (HD2/HD3):

    — -102 dBc/-97 dBc at 100 kHz, VOUTDIFF = 4 VP-P

  • High DC Linearity:

    — < ± 1LSB, 16-Bit, 8 VP-P

  • 3 mm x 3 mm 8-Pin DFN & 8-Lead MSOP Packages

Availability and Pricing

Fully specified commercial (0 to 70 degrees C), industrial (-40 to 85 degrees C) and extended (-40 to 125 degrees C) temperature range versions of the LT6350 are available in 8-lead MSOP and 3 mm x 3 mm DFN packages. Prices start at $2.59 each in quantities of 1,000 pieces.



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