The ADS1281 is an extremely high-performance, single-chip analog-to-digital converter (ADC) designed for the demanding needs of energy exploration and seismic monitoring environments. The single-chip design promotes board area savings for improvements in high-density applications.

The converter uses a fourth-order, inherently stable, delta-sigma () modulator that provides outstanding noise and linearity performance. The modulator is used either in conjunction with the on-chip digital filter, or can be bypassed for use with post-processing filters.

The digital filter consists of sinc and finite impulse response (FIR) low-pass stages followed by an infinite impulse response (IIR) high-pass filter (HPF) stage. Selectable decimation provides data rates from 250 to 4000 samples per second (SPS). The FIR low-pass stage provides both linear and minimum phase response. The HPF features an adjustable corner frequency. On-chip gain and offset scaling registers support system calibration.

The synchronization input (SYNC) can be used to synchronize the conversions of multiple ADS1281s. The SYNC input also accepts a clock input for continuous alignment of conversions from an external source.

Together, the modulator and filter dissipate only 12mW. The ADS1281 is available in a compact TSSOP-24 package and is fully specified from –40°C to +85°C, with a maximum operating range to +125°C.

• High Resolution:
  • 130dB SNR (250SPS)
  • 127dB SNR (500SPS)
• High Accuracy:
  • THD: –122dB (typ), –115dB (max)
  • INL: 0.6ppm
• Inherently Stable Modulator with Fast Responding Over-Range Detection
• Flexible Digital Filter:
  • Sinc + FIR + IIR (Selectable)
  • Linear or Minimum Phase Response
  • Programmable High-Pass Filter
  • Selectable FIR Data Rates:
    • 250SPS to 4kSPS
• Filter Bypass Option
• Low Power Consumption:
  • Operating: 12mW
  • Shutdown: 10µW
• Calibration Engine for Offset and Gain Correction
• SYNC Input
• Analog Supply:
  • Unipolar (+5V) or Bipolar (±2.5V)
• Digital Supply: 1.8V to 3.3V
• APPLICATIONS
  • Energy Exploration
  • Seismic Monitoring
  • High-Accuracy Instrumentation

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