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AD4111/AD4112 24-Bit Sigma-Delta Analog-to-Digital Converters (ADC)

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AD4111/AD4112 24-Bit Sigma-Delta Analog-to-Digital Converters (ADC)

Analog Devices’ ADCs for PLC and DCS modules

Analog Devices' AD4111 and AD4112 are low-power, low-noise, 24-bit sigma-delta (Σ-Δ) ADCs. These ADCs integrate an analog front end (AFE) for fully differential or single-ended high impedance (≥1 MΩ) bipolar, ±10 V voltage inputs and 0 mA to 20 mA current inputs.

The AD4111 and AD4112 integrate key analog and digital signal conditioning blocks to configure eight individual setups for each analog input channel in use. These ADCs feature a maximum channel scan rate of 6.2 kSPS (161 µs) for fully settled data. The embedded 2.5 V, low drift (5 ppm/°C) band gap internal reference (with output reference buffer) reduces the external component count.

The digital filter allows flexible settings, including simultaneous 50 Hz and 60 Hz rejection at a 27.27 SPS output data rate. The user can select between the different filter settings depending on the demands of each channel in the application. The automatic channel sequencer enables the ADC to switch through each enabled channel. The precision performance of these ADCs is achieved by integrating the proprietary iPassives™ technology and is factory calibrated to achieve a high degree of specified accuracy.

The AD4111 also has the unique feature of open wire detection on the voltage inputs (patent pending) for system level diagnostics using a single 5 V or 3.3 V power supply. The AD4111 and AD4112 operate with a single power supply, making them easy to use in galvanically isolated applications. The specified operating temperature range is -40°C to +105°C, and they come in a 40-lead, LFCSP package. They were designed specifically for use in PLC and DCS modules.

Features
  • 24-bit ADC with integrated analog front end
    • Up to 6.2 kSPS per channel (161 µs per channel)
    • 16 noise-free bits at 1 kSPS per channel
    • 85 dB rejection of 50 Hz and 60 Hz at 20 SPS per channel
  • ±10 V inputs, four differential and eight single-ended
    • Overrange up to ±20 V
    • ≥1 MΩ impedance
    • ±0.06% accuracy at 25°C
    • Open-wire detection
  • 0 mA to 20 mA inputs, four single-ended
    • Overrange up to -0.5 mA to +24 mA
    • 60 Ω impedance
    • ±0.08% accuracy at 25°C
  • On-chip 2.5 V reference
    • ±0.12% accuracy at 25°C, ±5 ppm/°C (typical) drift
  • Internal or external clock
  • Power supplies
    • AVDD = 3.0 V to 5.5 V
    • IOVDD = 2.0 V to 5.5 V
    • Total IDD = 3.9 mA
  • Temperature range: -40°C to +105°C
  • 3-wire or 4-wire serial digital interface (Schmitt trigger on SCLK)
    • SPI, QSPI, MICROWIRE, and DSP compatible
Applications
  • Process control
  • PLC and DCS modules