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The LTD2284 is a high-performance, single-chip, analog-to-digital converter (ADC). This device includes a low-noise programmable gain amplifier (A), delta-sigma (ΔΣ) modulator, and digital filter. The ADC supports two modes of operation with trade-offs between power and resolution.

The two-channel multiplexer has the inputs for signal measurement and an ADC signal test. A mode is available to short circuit the inputs and test for internal noise. The A has the high input impedance and low noise, which provides for the direct connection of geophone and hydrophone sensors.

The fourth-order, inherently stable modulator provides outstanding noise and linearity performance. The modulator output is filtered and decimated by the on-chip digital filter to yield the ADC conversion result.

The digital filter provides data rates from 250 to 4000 SPS. The high-pass filter (HPF) has a programmable corner frequency. On-chip gain and offset scale registers support system calibration.

The synchronization input controls the timing of the ADC conversion. The power-down input puts the ADC into power-down mode.

The ADS1284 is available in a compact 24-lead, 5-mm × 4-mm QFN package, and is fully specified from –40ºC to +85ºC, with a maximum operating temperature range of –50ºC to +125ºC.

• Selectable Operating Modes
  
• Low-Power Mode:
  -13 mW (A = 1, 2, 4 and 8)
  -128 dB SNR (250 SPS, A = 1)
  
• High-Resolution Mode:
  - 18 mW (A = 1, 2, 4 and 8)
  - 130 dB SNR (250 SPS, A = 1)
  
• THD: -110 dB
  
• CMRR: 110 dB
  
• Two-Channel Multiplexer
  
• Inherently-Stable Modulator
  
• Fast Responding Overrange Detector
  
• Flexible Digital Filter:
   - Sinc + FIR + IIR (Selectable)
   - Linear or Minimum Phase Option、
   - Programmable High-Pass Filter
  
• Offset and Gain Calibration
  
• SYNC Input
  
• Analog Supply: 5 V
  
• Digital Supply: 1.8 V to 3.3 V
  

• Energy Exploration
  
• Seismic Monitoring
  
• High-Accuracy Instrumentation