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FEATURES DESCRIPTION
APPLICATIONS
24−Bit
ADC
Digital
Filter
Internal
Monitoring
16:1
Analog
Input
MUX
1
16
AINCOM
…
ADC
In
Extclk
In/Out
AVSS DGND
AVDD DVDD
MUX
Out
SPI
Interface
CS
DRDY
SCLK
DIN
DOUT
ControlOscillator
GPIO
START
RESET
PWDN
GPIO[7:0]VREF
ADS1258
Analog Inputs
ADS1258
SBAS297A – JUNE 2005 – REVISED SEPTEMBER 2005
16-Channel, 24-Bit Analog-to-Digital Converter
• 24 Bits, No Missing Codes The ADS1258 is a 16-channel (multiplexed),
low-noise, 24-bit, delta-sigma ( ∆ Σ ) analog-to-digital• Fixed-Channel or Automatic Channel Scan
converter (ADC) that provides single-cycle settled• Fixed-Channel Data Rate: 125kSPS
data at channel scan rates from 1.8k to 23.7k• Auto-Scan Data Rate: 23.7kSPS
samples per second (SPS). A flexible input
• Single-Conversion Settled Data multiplexer accepts combinations of eight differential
or 16 single-ended inputs with a full-scale differential• 16 Single-Ended or 8 Differential Inputs
range of 5V or true bipolar range of ± 2.5V when• Unipolar (+5V) or Bipolar ( ± 2.5V) Operation
operating with a 5V reference. The fourth-order
• Low Noise: 2.8 µ V RMS at 1.8kSPS delta-sigma modulator is followed by a fifth-order sinc
digital filter optimized for low-noise performance.• 0.0003% Integral Nonlinearity
• DC Stability (typical): The differential output of the multiplexer is accessible
to allow signal conditioning prior to the input of the0.02 µ V/ ° C Offset Drift, 0.4ppm/ ° C Gain Drift
ADC. Internal system monitor registers provide• Open-Sensor Detection
supply voltage, temperature, reference voltage, gain,• Conversion Control (Pin and Commands)
and offset data.
• Multiplexer Output for External Signal An onboard PLL generates the system clock from a
Conditioning 32.768kHz crystal, or can be overridden by an
• On-Chip Temperature, Reference, Offset, external clock source. A buffered system clock output
Gain, and Supply Voltage Readback (15.7MHz) is provided to drive a microcontroller or
additional converters.• 42mW Power Dissipation
Serial digital communication is handled via an• Standby, Sleep, and Power-Down Modes
SPI ™ -compatible interface. A simple command word• 8 General-Purpose Inputs/Outputs (GPIO)
structure controls channel configuration, data rates,• 32.768kHz Crystal Oscillator or External Clock
digital I/O, monitor functions, etc.
Programmable sensor bias current sources can be
used to bias sensors or verify sensor integrity.• Medical, Avionics, and Process Control
The ADS1258 operates from a unipolar +5V or• Machine and System Monitoring
bipolar ± 2.5V analog supply and a digital supply• Fast Scan Multi-Channel Instrumentation
compatible with interfaces ranging from 2.7V to• Industrial Process Controls
5.25V. The ADS1258 is available in a QFN-48
• Test and Measurement Systems package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SPI is a trademark of Motorola, Inc.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright © 2005, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.