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.