ADS1287D - Low-Power, 1kSPS, 2-Ch (Simultaneous) Delta-Sigma ADC With PGA for Seismic and Energy Exploration

The ADS1287D device is a dual, simultaneous-sampling, analog-to-digital converter (ADC),with an integrated programmable gain amplifier (PGA) and finite-impulse-response (FIR) digitalfilter. The ADC is suitable for the demanding needs of low-power, seismic data acquisition.

The ADC features a programmable-gain, high-impedance amplifier suitable for directconnection of geophone and hydrophone sensors to the ADC over a wide range of input signals (±2.5 Vto ±0.156 V). Dual 100-nA current sources are integrated into the ADC inputs for field testing ofsensors.

The ADC incorporates a fourth-order, inherently stable, delta-sigma (ΔΣ) modulator. Themodulator digital output is filtered and decimated by the internal FIR digital filter to yield theADC conversion result.

The FIR digital filter provides data rates up to 1000 samples per second (SPS). Thehigh-pass filter (HPF) removes DC and low-frequency components from the conversion result. On-chipgain and offset scaling registers support system calibration.

Total device power consumption is 4.4 mW. The ADC is packaged in a compact 5-mm × 5-mmVQFN package and is fully specified over the –40°C to +85°C temperature range.

• SNR: 114 dB (50 Hz–200 Hz, Gain = 1)
• Power: 2.2 mW (Per ADC)
• THD: –115 dB
• CMRR: 110 dB
• High-Impedance CMOS PGA:
  • Gains 1, 2, 4, 8, and 16
• Data Rates: 62.5 SPS to 1000 SPS
• Flexible Digital Filter:
  • Sinc + FIR + IIR (Selectable)
  • Linear and Minimum Phase Response
  • Programmable High-Pass Filter
• Sensor-Test Current Sources
• Offset and Gain Calibration
• Synchronization Control
• SPI™-Compatible Interface
• Analog Power Supply: 5 V or ±2.5 V
• Digital Power Supply: 2.5 V to 3.3 V

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