4.8 kHz Ultralow Noise 24-Bit Sigma-Delta ADC with PGA Data Sheet AD7190 FEATURES Temperature measurement Chromatography RMS noise: 8.5 nV 4.7 Hz (gain = 128) PLC/DCS analog input modules 16 noise free bits 2.4 kHz (gain = 128) Data acquisition Up to 22.5 noise free bits (gain = 1) Medical and scientific instrumentation Offset drift: 5 nV/C Gain drift: 1 ppm/C GENERAL DESCRIPTION Specified drift over time The AD7190 is a low noise, complete analog front end for high 2 differential/4 pseudo differential input channels precision measurement applications. It contains a low noise, Automatic channel sequencer 24-bit sigma-delta (-) analog-to-digital converter (ADC). Programmable gain (1 to 128) The on-chip low noise gain stage means that signals of small Output data rate: 4.7 Hz to 4.8 kHz amplitude can be interfaced directly to the ADC. Internal or external clock The device can be configured to have two differential inputs or Simultaneous 50 Hz/60 Hz rejection four pseudo differential inputs. The on-chip channel sequencer 4 general-purpose digital outputs allows several channels to be enabled, and the AD7190 Power supply sequentially converts on each enabled channel. This simplifies AV : 4.75 V to 5.25 V DD DV : 2.7 V to 5.25 V communication with the part. The on-chip 4.92 MHz clock can DD Current: 6 mA be used as the clock source to the ADC or, alternatively, an Temperature range: 40C to +105C external clock or crystal can be used. The output data rate from Interface the part can be varied from 4.7 Hz to 4.8 kHz. 3-wire serial The device has two digital filter options. The choice of filter SPI, QSPI, MICROWIRE, and DSP compatible affects the rms noise/noise-free resolution at the programmed Schmitt trigger on SCLK output data rate, the settling time, and the 50 Hz/60 Hz Qualified for automotive applications rejection. For applications that require all conversions to be settled, the AD7190 includes a zero latency feature. APPLICATIONS The part operates with 5 V analog power supply and a digital Weigh scales power supply from 2.7 V to 5.25 V. It consumes a current of Strain gauge transducers 6 mA. It is housed in a 24-lead TSSOP package. Pressure measurement FUNCTIONAL BLOCK DIAGRAM AGND AV DV DGND REFIN1(+) REFIN1() DD DD REFERENCE DETECT AD7190 AIN1 AIN2 AIN3 DOUT/RDY SERIAL AIN4 INTERFACE MUX DIN - AINCOM PGA AND ADC CONTROL SCLK LOGIC CS SYNC TEMP P3 SENSOR P2 BPDSW CLOCK CIRCUITRY AGND MCLK1 MCLK2 P0/REFIN2() P1/REFIN2(+) Figure 1. Rev. C Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20082013 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 07640-001AD7190 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Full-Scale Register ...................................................................... 25 Applications ....................................................................................... 1 ADC Circuit Information .............................................................. 26 General Description ......................................................................... 1 Overview ..................................................................................... 26 Functional Block Diagram .............................................................. 1 Filter, Output Data Rate, Settling Time ................................... 26 Revision History ............................................................................... 2 Digital Interface .......................................................................... 29 Specif icat ions ..................................................................................... 3 Circuit Description......................................................................... 33 Timing Characteristics ................................................................ 7 Analog Input Channel ............................................................... 33 Circuit and Timing Diagrams ..................................................... 7 PGA .............................................................................................. 33 Absolute Maximum Ratings ............................................................ 9 Bipolar/Unipolar Configuration .............................................. 33 Thermal Resistance ...................................................................... 9 Data Output Coding .................................................................. 33 ESD Caution .................................................................................. 9 Clock ............................................................................................ 33 Pin Configuration and Function Descriptions ........................... 10 Burnout Currents ....................................................................... 34 Typical Performance Characteristics ........................................... 12 Reference ..................................................................................... 34 RMS Noise and Resolution ............................................................ 15 Reference Detect ......................................................................... 34 4 Sinc Chop Disabled ................................................................... 15 Reset ............................................................................................. 34 3 Sinc Chop Disabled ................................................................... 16 System Synchronization ............................................................ 35 4 Sinc Chop Enabled .................................................................... 17 Temperature Sensor ................................................................... 35 3 Sinc Chop Enabled .................................................................... 18 Bridge Power-Down Switch ...................................................... 35 On-Chip Registers .......................................................................... 19 Logic Outputs ............................................................................. 35 Communications Register ......................................................... 19 Enable Parity ............................................................................... 36 Status Register ............................................................................. 20 C a l ibr at ion ................................................................................... 36 Mode Register ............................................................................. 20 Grounding and Layout .............................................................. 37 Configuration Register .............................................................. 22 Applications Information .............................................................. 38 Data Register ............................................................................... 24 Weigh Scales ................................................................................ 38 ID Register ................................................................................... 24 Outline Dimensions ....................................................................... 39 GPOCON Register ..................................................................... 24 Ordering Guide .......................................................................... 39 Offset Register ............................................................................. 25 Automotive Products ................................................................. 39 REVISION HISTORY Changes to Table 20 ....................................................................... 24 2/13Rev. B to Rev. C Added ID Register Section ............................................................ 24 Added Automotive Information (Throughout) ........................... 1 Changes to Table 21 ....................................................................... 25 Added Automotive Specifications, Table 1 .................................... 3 Changes to Filter, Output Data Rate, Settling Time Section .... 26 Changes to Ordering Guide .......................................................... 39 Changes to Continuous Conversion Mode Section ................... 31 5/09Rev. A to Rev. B Changes to Analog Input Channel and Bipolar/Unipolar Configuration Sections .................................................................. 33 Changes to Table 3 ............................................................................ 9 Changes to Burnout Currents, Reference, Reference Detect, and 5/09Rev. 0 to Rev. A Reset Sections .................................................................................. 34 Changes to Table 1 ............................................................................ 3 Changes to Temperature Sensor Section ..................................... 35 Changes to Table 3 and Table 4 ....................................................... 9 Changes to Calibration Section .................................................... 36 Changes to Table 5 .......................................................................... 10 Changes to Grounding and Layout Section ................................ 37 Changes to Table 6 and Table 7 ..................................................... 15 Changes to Weigh Scales Section ................................................. 38 Changes to Status Register Section .............................................. 20 Changes to Ordering Guide .......................................................... 39 Changes to Table 17 ........................................................................ 21 10/08Revision 0Initial Version Changes to Table 19 ........................................................................ 23 Rev. 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