1FEATURES
2• 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: 10mW
• 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

DESCRIPTION
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 (ΔΣ) 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.