12-Bit Low Power Sigma-Delta ADC Data Sheet AD7170 FEATURES FUNCTIONAL BLOCK DIAGRAM Output data rate: 125 Hz GND V REFIN(+) REFIN() DD Pin-programmable power-down and reset Status function AIN(+) DOUT/RDY 12-BIT - Internal clock oscillator ADC AIN() SCLK Current: 135 A PDRST Power supply: 2.7 V to 5.25 V INTERNAL AD7170 CLOCK 40C to +105C temperature range Package: 10-lead, 3 mm 3 mm LFCSP Figure 1. INTERFACE Table 1. 2-wire serial (read-only device) P-P SPI compatible VREF = VDD RMS Noise P-P Noise Resolution ENOB Schmitt trigger on SCLK 5 V 11.5 V 76 V 12 bits 12 bits 3 V 6.9 V 45 V 12 bits 12 bits APPLICATIONS Pressure measurement Industrial process control Portable instrumentation GENERAL DESCRIPTION The AD7170 is a very low power 12-bit analog-to-digital converter The output data rate of the AD7170 is 125 Hz, whereas the (ADC). It contains a precision 12-bit sigma-delta (-) ADC settling time is 24 ms. The AD7170 has one differential input and an on-chip oscillator. Consuming only 135 A, the AD7170 and a gain of 1. This is useful in applications where the user is particularly suitable for portable or battery operated products needs to use an external amplifier to implement system-specific where very low power is a requirement. The AD7170 also has a filtering or gain requirements. power-down mode in which the device consumes 5 A, thus The AD7170 operates with a power supply from 2.7 V to 5.25 V. increasing the battery life of the product. It is available in a 10-lead LFCSP package. For ease-of-use, all the features of the AD7170 are controlled by The AD7171 is a 16-bit version of the AD7170. It has the same dedicated pins. Each time a data read occurs, eight status bits feature set as the AD7170 and is pin-for-pin compatible. are appended to the 12-bit conversion. These status bits contain a pattern sequence that can be used to confirm the validity of the serial transfer. Rev. 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Technical Support www.analog.com 08416-001AD7170 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Overview ..................................................................................... 10 Interface ............................................................................................. 1 Filter, Data Rate, and Settling Time ......................................... 10 Applications ....................................................................................... 1 Gain .............................................................................................. 10 Functional Block Diagram .............................................................. 1 Power-Down/Reset (PDRST) ................................................... 10 General Description ......................................................................... 1 Analog Input Channel ............................................................... 10 Revision History ............................................................................... 2 Bipolar Configuration ................................................................ 10 Specif icat ions ..................................................................................... 3 Data Output Coding .................................................................. 11 Timing Characteristics ..................................................................... 5 Reference ..................................................................................... 11 Timing Diagrams .......................................................................... 5 Digital Interface .......................................................................... 11 Absolute Maximum Ratings ............................................................ 6 Grounding and Layout .............................................................. 12 Thermal Resistance ...................................................................... 6 Applications Information .............................................................. 13 ESD Caution .................................................................................. 6 Temperature System ................................................................... 13 Pin Configuration and Function Descriptions ............................. 7 Signal Conditioning Circuit ...................................................... 13 Typical Performance Characteristics ............................................. 8 Outline Dimensions ....................................................................... 14 Output Noise and Resolution Specifications ................................ 9 Ordering Guide .......................................................................... 14 ADC Circuit Information .............................................................. 10 REVISION HISTORY 6/15Rev. A to Rev. B Changed Pin 10, NC to Pin 10, GND ......................... Throughout Changes to Figure 5 and Table 5 ..................................................... 7 Changes to Figure 14 ...................................................................... 13 Changes to Figure 15 ...................................................................... 14 Updated Outline Dimensions ....................................................... 14 9/11Rev. 0 to Rev. A Changes to Digital Interface Section ............................................ 11 Updated Outline Dimensions ....................................................... 14 Changes to Ordering Guide .......................................................... 14 10/09Revision 0: Initial Version Rev. B Page 2 of 14