FEATURES
24 Bits, No Missing Codes
− All Data Rates and PGA Settings
Up to 23 Bits Noise-Free Resolution
±0.0010% Nonlinearity (max)
Data Output Rates to 30kSPS
Fast Channel Cycling
− 18.6 Bits Noise-Free (21.3 Effective Bits)
at 1.45kHz
One-Shot Conversions with Single-Cycle
Settling
Flexible Input Multiplexer with Sensor Detect
− Four Differential Inputs (ADS1256 only)
− Eight Single-Ended Inputs (ADS1256 only)
Chopper-Stabilized Input Buffer
Low-Noise PGA: 27nV Input-Referred Noise
Self and System Calibration for All PGA
Settings
5V Tolerant SPI™-Compatible Serial Interface
Analog Supply: 5V
Digital Supply: 1.8V to 3.6V
Power Dissipation
− As Low as 38mW in Normal Mode
− 0.4mW in Standby Mode

APPLICATIONS
Scientific Instrumentation
Industrial Process Control
Medical Equipment
Test and Measurement
Weigh Scales

DESCRIPTION
The ADS1255 and ADS1256 are extremely low-noise,
24-bit analog-to-digital (A/D) converters. They provide
complete high-resolution measurement solutions for the
most demanding applications.
The converter is comprised of a 4th-order, delta-sigma
(ΔΣ) modulator followed by a programmable digital filter. A
flexible input multiplexer handles differential or
single-ended signals and includes circuitry to verify the
integrity of the external sensor connected to the inputs.
The selectable input buffer greatly increases the input
impedance and the low-noise programmable gain
amplifier (PGA) provides gains from 1 to 64 in binary steps.
The programmable filter allows the user to optimize
between a resolution of up to 23 bits noise-free and a data
rate of up to 30k samples per second (SPS). The
converters offer fast channel cycling for measuring
multiplexed inputs and can also perform one-shot
conversions that settle in just a single cycle.
Communication is handled over an SPI-compatible serial
interface that can operate with a 2-wire connection.
Onboard calibration supports both self and system
correction of offset and gain errors for all the PGA settings.
Bidirectional digital I/Os and a programmable clock output
driver are provided for general use. The ADS1255 is
packaged in an SSOP-20, and the ADS1256 in an
SSOP-28.