SEN-15242 SparkFun

NAU7802 24-bit ADC NAU7802 24-Bit Dual-Channel ADC For Bridge Sensors Date: January, 2012 Revision 1.7 Nuvoton Confidential - 1 - Revision 1.7 NAU7802 24-bit ADC Table of Contents 1 GENERAL DESCRIPTION ......................................................................................................... 4 2 SYSTEM BLOCK DIAGRAM ...................................................................................................... 4 3 FEATURES ................................................................................................................................. 4 4 APPLICATIONS .......................................................................................................................... 5 5 PIN CONFIGURATION ............................................................................................................... 6 6 PIN DESCRIPTION ..................................................................................................................... 6 7 ELECTRICAL CHARACTERISTICS ........................................................................................... 7 7.1 Absolute Maximum Ratings ............................................................................................ 7 7.2 DC ELECTRICAL CHARACTERISTICS ........................................................................ 7 7.3 RC OSC AND AC CHARACTERISTICS ........................................................................ 9 7.4 TEMPERATURE SENSOR............................................................................................. 9 7.5 Typical Characteristic .................................................................................................... 10 7.5.1 NAU7802 Linearity (Error % vs. Input Voltage) ............................................................10 7.5.2 Noise Performance NAU7802 ......................................................................................11 7.5.3 ESD Performance NAU7802 ........................................................................................11 7.6 DIGITAL SERIAL INTERFACE TIMING ....................................................................... 12 8 FUNCTIONAL DESCRIPTION .................................................................................................. 13 8.1 Analog input (VIN1P, VIN1N, VIN2N, VIN2P) .............................................................. 13 8.2 Power supply ................................................................................................................ 13 2 8.3 2-Wire-Serial Control and Data Bus (I C Style Interface) ............................................ 13 8.3.1 2-Wire Protocol Convention ............................................................................................14 8.3.2 2-Wire Write Operation ...................................................................................................16 8.3.3 2-Wire Single Read Operation ........................................................................................16 8.4 2-Wire Timing ................................................................................................................ 17 8.5 NAU7802 Streaming Data Mode .................................................................................. 18 8.5.1 Enabling the Streaming I2C Mode ..................................................................................18 8.5.2 Streaming I2C Mode R/W Protocol 1 ..............................................................................18 8.5.3 Streaming I2C Mode R/W Protocol 2 ..............................................................................19 8.6 Device Calibration Features ......................................................................................... 20 8.6.1 Internal or External calibration.........................................................................................20 8.6.2 Calibration Limitations .....................................................................................................21 8.6.3 Calibration Error ..............................................................................................................21 8.7 Internal Band-Gap Circuit ................................................................................................ 22 8.8 Reset and Power-down mode ...................................................................................... 22 8.9 Temperature sensor ...................................................................................................... 23 8.10 Oscillator Features ........................................................................................................ 24 8.10.1 External Crystal Oscillator .............................................................................................24 8.10.2 External Clock Source ...................................................................................................24 9 APPLICATION INFORMATION ................................................................................................ 25 9.1 Power-On Sequencing .................................................................................................. 25 9.2 Signal path normal operation ........................................................................................ 25 9.3 Signal path with PGA bypass enabled .......................................................................... 26 Nuvoton Confidential - 2 - Revision 1.7