ADS8881 SAR ADC

ADS8881 SAR ADC

Texas Instruments' ADS8881 is an 18-bit, 1 MSPS, true-differential input, analog-to-digital converter (ADC). The device operates with a 2.5 to 5 V external reference, offering a wide selection of signal ranges without additional input signal scaling. The reference voltage setting is independent of, and can exceed, the analog supply voltage (AVDD).

The device offers an SPI-compatible serial interface that also supports daisy-chain operation for cascading multiple devices. An optional busy-indicator bit makes synchronizing with the digital host easy.

The device supports unipolar, true-differential analog input signals with a differential input swing of –VREF to VREF. This true-differential analog input structure allows for a common-mode voltage of any value in the range of 0 V to VREF (when both inputs are within the operating input range of –0.1 V to VREF +0.1 V).

Features  
  • Sample rate: 1 MHz
  • No latency output
  • Unipolar, true-differential input range: –VREF to +VREF
  • Wide common-mode voltage range: 0 V to VREF with 90 dB CMRR (min)
  • SPI™-compatible serial interface with daisy-chain option
  • Wide operating range
  • Power-down current (AVDD): 50 nA
  • Full-scale step settling to 18 bits: 290 ns
  • Excellent AC and DC performance:
    • ADS8881C:
      INL: ±1 LSB (typ), ±2.0 LSB (max)
      DNL: ±1.0 LSB (max), 18-bit NMC
      SNR: 100 dB, THD: –115 dB
    • ADS8881I:
      INL: ±1.5 LSB (typ), ±3.0 LSB (max)
      DNL: +1.5 and –1 LSB (max), 18-bit NMC
      SNR: 100 dB, THD: –115 dB

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