NAU7802SGI

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 2 3 4 5 6 7 GENERAL DESCRIPTION ......................................................................................................... 4 SYSTEM BLOCK DIAGRAM ...................................................................................................... 4 FEATURES ................................................................................................................................. 4 APPLICATIONS .......................................................................................................................... 5 PIN CONFIGURATION ............................................................................................................... 6 PIN DESCRIPTION ..................................................................................................................... 6 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 7.5.2 7.5.3 8 7.6 DIGITAL SERIAL INTERFACE TIMING ....................................................................... 12 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 8.3.2 8.3.3 8.4 8.5 8.6 Enabling the Streaming I2C Mode ..................................................................................18 Streaming I2C Mode R/W Protocol 1 ..............................................................................18 Streaming I2C Mode R/W Protocol 2 ..............................................................................19 Device Calibration Features ......................................................................................... 20 8.6.1 8.6.2 8.6.3 8.7 8.8 8.9 8.10 2-Wire Protocol Convention ............................................................................................14 2-Wire Write Operation ...................................................................................................16 2-Wire Single Read Operation ........................................................................................16 2-Wire Timing ................................................................................................................ 17 NAU7802 Streaming Data Mode .................................................................................. 18 8.5.1 8.5.2 8.5.3 Internal or External calibration.........................................................................................20 Calibration Limitations .....................................................................................................21 Calibration Error ..............................................................................................................21 Internal Band-Gap Circuit ................................................................................................ 22 Reset and Power-down mode ...................................................................................... 22 Temperature sensor ...................................................................................................... 23 Oscillator Features ........................................................................................................ 24 8.10.1 8.10.2 9 NAU7802 Linearity – (Error % vs. Input Voltage) ............................................................10 Noise Performance – NAU7802 ......................................................................................11 ESD Performance – NAU7802 ........................................................................................11 External Crystal Oscillator .............................................................................................24 External Clock Source...................................................................................................24 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 NAU7802 24-bit ADC 10 11 9.4 16-pin application circuit ............................................................................................... 27 SUMMARY DEVICE REGISTER MAP ..................................................................................... 28 DEVICE REGISTER MAP DETAILS......................................................................................... 29 11.1 REG0x00:PU_CTRL ..................................................................................................... 29 11.2 REG0x01:CTRL1 .......................................................................................................... 30 11.3 REG0x02:CTRL2 .......................................................................................................... 31 11.4 REG0x03-REG0x05: Channel 1 OFFSET Calibration ................................................. 32 11.5 REG0x06-REG0x09: Channel 1 GAIN Calibration ....................................................... 32 11.6 REG0x0A-REG0x0C: Channel 2 OFFSET Calibration (NAU7802 - only) ................... 32 11.7 REG0x0D-REG0x10: Channel 2 GAIN Calibration (NAU7802 - only) ......................... 32 11.8 REG0x11: I2C Control .................................................................................................. 33 11.9 REG0x12-REG0x14: ADC Conversion Result ............................................................. 34 11.10 REG0x15: ADC registers .......................................................................................... 35 REG0x15-REG0x17: OTP Read Value and REG0x15 ADC Registers Read .......................... 36 11.11 REG0x18: Read Only ............................................................................................... 36 11.12 REG0x19: Read Only ............................................................................................... 36 11.13 REG0x1A: Read Only............................................................................................... 36 11.14 REG0x1B: PGA Registers ........................................................................................ 36 11.15 REG0x1C: POWER CONTROL Register ................................................................. 37 11.15.1 11.15.2 11.15.3 12 13 14 REG0x1D: Read Only .................................................................................................37 REG0x1E: Read Only .................................................................................................37 REG0x1F: Read Only .................................................................................................37 PACKAGE DIMENSIONS ......................................................................................................... 38 12.1 16L SOP – 150 mil ........................................................................................................ 38 12.2 PDIP16L - 300 mil ......................................................................................................... 39 PART ORDERING INFORMATION .......................................................................................... 40 REVISION HISTORY ................................................................................................................ 41 Nuvoton Confidential -3- Revision 1.7 NAU7802 24-bit ADC 1 GENERAL DESCRIPTION The Nuvoton NAU7802 is a precision low-power 24-bit analog-to-digital converter (ADC), with an onboard low-noise programmable gain amplifier (PGA), onboard RC or Crystal oscillator, and a precision 24-bit sigma-delta (Σ-Δ) analog to digital converter (ADC). The NAU7802 device is capable of up to 23-bit ENOB (Effective Number Of Bits) performance. This device provides a complete front-end solution for bridge/sensor measurement such as in weigh scales, strain gauges, and many other high resolution, low sample rate applications. The many built-in features enable high performance applications with very low external parts count. Additionally, both operating current and standby current are very low, and many power management features are included. These enable powering only those elements of the chip that are needed, and also, to operate at greatly reduced power if the full 23-bit ENOB performance is not required. The Programmable Gain Amplifier (PGA) provides selectable gains from 1 to 128. The A/D conversion is performed with a Sigma-Delta modulator and programmable FIR filter that provides a simultaneous 50Hz and 60Hz notch filter to effectively improve interference immunity. Also, this device provides a standard 2-wire interface compatible with I2C protocol for simple and straightforward connection to and interoperation with a wide range of possible host processors. 2 SYSTEM BLOCK DIAGRAM VBG Bandgap Reference 2.7V~5.5V Input DVDD AVDD XOUT To serial Interface IO Power LDO To Analog Circuit XIN 1 LDO VLDO [1:0] Internal RC Oscillator 0 digital logic OSCS Control Signal CRS[2:0] CHS VIN1P SCLK PGA[1:0] Digital DRDY VIN2P VIN1N SDIO 14 24- bit ADC PGA ADC result Interface 24 VIN2N Temperature Sensor AVSS Nuvoton Confidential REFP -4- REFN DVSS Revision 1.7 NAU7802 24-bit ADC 3                   4       FEATURES Supply power: 2.7V~5.5V On-chip VDDA regulator for internal analog circuit or external load cell  Programmable VDDA: Off, 2.4V to 4.5V with eight options Minimum 10mA output drive capability at 3.0V output voltage Note: DVDD must be 0.3Vdc greater than desired VDDA output voltage 23 bits effective precision analog-to-digital converter Simultaneous 50Hz and 60Hz rejection (reaching －90dB） RMS Noise:  50nV in 10 SPS data output rate and PGA gain = 128  150nV in 80 SPS data output rate and PGA gain = 128 Programmable PGA gains from 1 to 128 Programmable ADC data output rates External differential reference voltage range from 0.1V to 5V System clock: External crystal oscillator or on-chip RC oscillator (4.9152Mhz) On-chip calibration On-chip power-on reset circuit On-chip temperature sensor Low Power Consumption and Programmable Power Management Options  < 1uA standby current External 4.9152MHz Crystal oscillator System clock:  Internal 4.9152MHz RC oscillator (power-on default system clock)  External 4.9152MHz Crystal oscillator MCU control interface: 2-wire interface compatible with I2C protocol Operating Temperature: -40~85C Packages:  SOP-16 (150mil) / PDIP-16 APPLICATIONS Weigh scales Strain Gauge Industrial process control Liquid/gas flow control Pressure sensors Voltage monitors Nuvoton Confidential -5- Revision 1.7 NAU7802 24-bit ADC 5 6 PIN CONFIGURATION REFP 1 16 AVDD/LDO VIN1N 2 15 DVDD VIN1P 3 14 SDIO 13 SCLK 12 DRDY 11 XOUT XIN SOP-16 (150mil) or DIP-16 VIN2N 4 VIN2P 5 VBG 6 REFN 7 10 AVSS 8 9 DVSS PIN DESCRIPTION Pin No. Pin Name Type DESCRIPTIONS 1 REFP AI Positive reference input 2 VIN1N AI Inverting Input #1 3 VIN1P AI Non-Inverting Input #1 4 VIN2N AI Inverting Input #2 5 VIN2P AI Non-Inverting Input #2 6 VBG A High impedance Reference Voltage Output and Bypass 7 REFN AI Negative Reference Input 8 AVSS P Analog Ground 9 DVSS P Digital ground 10 XIN I External crystal oscillator input. Typically 4.9152 MHz 11 XOUT O External crystal oscillator output. 12 DRDY O Data Ready Output indicating a conversion is complete and new data are available for readout. (CMOS Driver high / low) 13 SCLK I Serial Data Clock Input (CMOS open drain output) 14 SDIO 15 DVDD P Digital power supply: 2.7V ~ 5.5V 16 AVDD/LDO P Analog power supply: 1. From programmable LDO output, low ESR 1 ohm or less capacitor recommended 2. LDO off: external power supply: 2.7V ~ 5.5V  I/O Data Input / Output for serial communication with host (CMOS open drain output) Note : TYPE P: Power, AI: Analog input, AO: Analog output, I: input, O: output, I/O: bi-directional Nuvoton Confidential -6- Revision 1.7 NAU7802 24-bit ADC 7 7.1 ELECTRICAL CHARACTERISTICS Absolute Maximum Ratings SYMBOL PARAMETER CONDITION MINIMUM MAXIMUM UNIT DVDD DVDDDVSS -0.3 +6.0 V AVDD* AVDDAVSS -0.3 +6.0 V AVSSDVSS - -0.3 +0.3 V Analog Input Voltage AVIN AVIN  AVSS -0.3 AVDD + 0.3 V Digital input Voltage DVIN DVIN  DVSS -0.3 DVDD + 0.3 V DC Power Supply Operating Temperature TA -40 +85 C Storage Temperature Tst -55 +150 C Note: Exposure to conditions beyond those listed under absolute maximum ratings may adversely affects the life time and reliability * AVDD should not exceed DVDD supply voltage 7.2 DC ELECTRICAL CHARACTERISTICS (Unless otherwise specified; Typical value is tested at TA=25C, DVDD = 5V, AVDD = 5V) PARAMETER SPECIFICATION MIN. TYP. MAX. UNIT TEST CONDITIONS POWER SUPPLY Operating Voltage Operating Current Power Down Current Nuvoton Confidential 2.7 5.5 V DVDD 2.7 DVDD V AVDD 2.1 mA Internal OSC & LDO 2 mA Internal OSC, no LDO A All analog part include internal RC oscillator or external crystal oscillator. PUA =PUD=0 0.2 1 -7- Revision 1.7 NAU7802 24-bit ADC ANALOG INPUT Full-scale input range (VINxP – VINxN) ± 0.5/(VREF/PGA) V Common mode range with PGA gain 64, 128 AVSS + 1.5 AVDD – 1.5 V Common mode range with PGA bypass enabled AVSS 0.1 AVDD + 0.1 V Differential input impedance Bandwidth (-3dB) PGA VREF = REFP  REFN 5 GΩ PGA bypass=off, DC 2.27 Hz Data output rate = 10 SPS Hz Data output rate = 80 SPS 18.17 1 128 User-selectable gain range Input capacitance channel 1 14 pF Input capacitance channel 2 5 pF Differential Input leakage current 20 pA Burnout current sources 2.5 A PGA bypass=off SYSTEM PERFORMANCE Resolution 24 Integral nonlinearity NAU7802 Offset error No missing codes ± 0.0015 % of FS +/-0.3 ppm of FS With calibration With calibration, 1024 samples Offset error drift 0.02 ppm of FS/C With calibration Gain error 0.01 % With calibration With calibration Gain error drift 1 ppm/C 100 dB at DC 2.5 V ± 0.5 V 130 dB fCM = 60 Hz, 500 mVpp ADC data rate = 10 SPS 120 dB fCM = 50 Hz, 500 mVpp ADC data rate = 10 SPS 100 dB fCM = 60 Hz, 500 mVpp ADC data rate = 10 SPS 100 dB fCM = 50 Hz, 500 mVpp ADC data rate = 10 SPS 96 100 dB at DC 5 V ± 0.25 V, with LDO VREF = REFP  REFN 1.5 AVDD REFN input range REFP input range 96 Common-mode rejection Notch rejection Power supply rejection VOLTAGE REFERENCE INPUT Nuvoton Confidential AVDD+. 0.1 V -0.1 VREFP1.5 V VREFN+ 1.5 AVDD+ 0.1 -8- Revision 1.7 NAU7802 24-bit ADC DIGITAL SERIAL INTERFACE Input Leakage Current SCK, SI Input High Voltage VIH -1 - +1 A DVDD = 5.5V, 0