AD7606C-18 Datasheet

• 18-bit ADC with 1 MSPS on all channels
• Input buffer with 1 MΩ minimum analog input impedance (R_IN)
• Single 5 V analog supply and 1.71 V to 5.25 V V_DRIVE
• Per channel selectable analog input ranges
  • Bipolar single-ended: ±12.5 V, ±10 V, ±6.25 V, ±5 V, ±2.5 V
  • Unipolar single-ended: 0 V to 12.5 V, 0 V to 10 V, 0 V to 5 V
  • Bipolar differential: ±20 V, ±12.5 V, ±10 V, ±5 V
• Two bandwidth options: 25 kHz and 220 kHz, per channel
• Flexible digital filter, oversampling ratio up to 256
• −40°C to +125°C operating range
• ±21 V input clamp protection with 6 kV ESD
• Pin to pin compatible to the AD7606B, AD7608, and AD7609

• Performance
  • 93 dB typical SNR for ±20 V bipolar differential range
  • 102 dB SNR, oversampling by 32
  • −100 dB typical THD for all other ranges
  • TUE = 0.05% of FSR maximum, external reference
  • ±0.5 ppm/°C typical PFS and NFS error drift
  • ±3 ppm/°C typical reference temperature coefficient
• Calibration and Diagnostics
  • Per channel system phase, offset, and gain calibration
  • Analog input open circuit detection feature
  • Self diagnostics and monitoring features
  • CRC error checking on read and write data and registers

• Power line monitoring
• Protective relays
• Multiphase motor control
• Instrumentation and control systems
• Data acquisition systems

The AD7606C-18 is an 18-bit, simultaneous sampling, analog-to-digital data acquisition system (DAS) with eight channels. Each channel contains analog input clamp protection, a programmable gain amplifier (PGA), a low-pass filter (LPF), and an 18-bit successive approximation register (SAR) analog-to-digital converter (ADC). The AD7606C-18 also contains a flexible digital filter, a low drift, 2.5 V precision reference, a reference buffer to drive the ADC, and flexible parallel and serial interfaces.

The AD7606C-18 operates from a single 5 V supply and accommodates the following input ranges when sampling at throughput rates of 1 MSPS for all channels:

• Bipolar single-ended: ±12.5 V, ±10 V, ±6.25 V, ±5 V, and ±2.5 V
• Unipolar single-ended: 0 V to 12.5 V, 0 V to 10 V, and 0 V to 5 V
• Bipolar differential: ±20 V, ±12.5 V, ±10 V, and ±5 V

The input clamp protection tolerates voltages up to ±21 V. The single supply operation, on-chip filtering, and high input impedance eliminate the need for external driver op amps, which require bipolar supplies. For applications with lower throughput rates, the AD7606C-18 flexible digital filter can be used to improve noise performance.

In hardware mode, the AD7606C-18 is fully compatible with the AD7608 and AD7609. In software mode, the following advanced features are available:

• Analog input range selectable per channel with added ranges available
• High bandwidth mode (220 kHz) selectable per channel
• Additional oversampling options with an oversampling ratio up to 256
• System gain, system offset, and system phase calibration, per channel
• Analog input open circuit detector
• Diagnostic multiplexer
• Monitoring functions (serial peripheral interface (SPI) invalid read and write, cyclic redundancy check (CRC), busy stuck monitor, and reset detection)

Note that throughout the data sheet, multifunction pins, such as the RD/SCLK pin, are referred to either by the entire pin name or by a single function of the pin, for example, the SCLK pin, when only that function is relevant.