The LTD2284 is a high-performance, single-chip, analog-to-digital converter (ADC). This device includes a low-noise programmable gain amplifier (PGA), 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 PGA 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 (PGA = 1, 2, 4 and 8)
  -128 dB SNR (250 SPS, PGA = 1)
  
• High-Resolution Mode:
  - 18 mW (PGA = 1, 2, 4 and 8)
  - 130 dB SNR (250 SPS, PGA = 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