ADS8881 - 18-Bit, 1MSPS, Serial Interface, microPower, True Differential-Input SAR ADC

The ADS8881 is an 18-bit, 1-MSPS, true-differential input, analog-to-digital converter (ADC). The device operates with a 2.5-V 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 –V_REF to V_REF. This true-differential analog input structure allows for a common-mode voltage of any value in the range of 0 V to V_REF (when both inputs are within the operating input range of –0.1 V to V_REF + 0.1 V).

Device operation is optimized for very low-power operation. Power consumption directly scales with speed. This feature makes the ADS8881 excellent for lower-speed applications.

• Sample Rate: 1 MHz
• No Latency Output
• Unipolar, True-Differential Input Range:
  –V_REF to +V_REF
• Wide Common-Mode Voltage Range:
  0 V to V_REF with 90-dB CMRR (min)
• SPI™-Compatible Serial Interface with
  Daisy-Chain Option
• 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
• Wide Operating Range:
  • AVDD: 2.7 V to 3.6 V
  • DVDD: 2.7 V to 3.6 V
    (Independent of AVDD)
  • REF: 2.5 V to 5 V (Independent of AVDD)
  • Operating Temperature:
    ADS8881C : 0°C to +70°C
    ADS8881I : –40°C to +85°C
• Low-Power Dissipation:
  • 5.5 mW at 1 MSPS
  • 0.55 mW at 100 kSPS
  • 55 µW at 10 kSPS
• Power-Down Current (AVDD): 50 nA
• Full-Scale Step Settling to 18 Bits: 290 ns
• Packages: MSOP-10 and VSON-10