AD7291Data SheetTYPICAL PERFORMANCE CHARACTERISTICS01.0VDD = VDRIVE = 3V f0.8S = 22.22ksps–20fSCL = 400kHz f0.6IN = 10kHzSNR = 71.2090.4–40THD = –81.66B)TA = 25°Cd)0.2(VBDRIVE = 3VVLSDD = 3VUDE–600fITL (S = 22.22kspsLINfP–0.2SCL = 400kHzAM–80–0.4–0.6–100INL (POSITIVE)–0.8INL (NEGATIVE)–120–1.002k4k6k8k10k 009 00.51.01.52.02.53.0 012 FREQUENCY (Hz)V 08711- REF (V) 08711- Figure 4. Typical FFT Figure 7. INL vs. External VREF 1.01.0TA = 25°C0.8VDRIVE = 3V0.8VREF = 2.5V0.6VDD = 3V0.6fS = 22.22ksps0.4f0.4SCL = 400kHzT)0.20.2A = 25°CBB)VSDRIVE = 3VLS0L (0VDD = 3VL (fS = 22.22kspsIN–0.2DNL–0.2fSCL = 400kHz–0.4–0.4–0.6–0.6DNL (POSITIVE)–0.8–0.8DNL (NEGATIVE)–1.0–1.005001000150020002500300035004096 010 00.51.01.52.02.53.0 013 ADC CODE 08711- VREF (V) 08711- Figure 5. Typical ADC INL Figure 8. DNL vs. External VREF 1.011.70.80.611.6ITS0.4OF B0.2R11.5B)ESBL0(M U NDNL–0.2E11.4TIV–0.4TA = 25°CCVDRIVE = 3VFFE–0.6VREF = 2.5VE11.3VDD = 3V–0.8fS = 22.22ksps fSCL = 400kHz–1.011.205001000150020002500300035004096 011 00.51.01.52.02.5 035 ADC CODE 08711- EXTERNAL REFERENCE (V) 08711- Figure 6. Typical ADC DNL Figure 9. Effective Number of Bits vs. VREF, fSCL = 400 kHz Rev. C | Page 8 of 28 Document Outline FEATURES FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION PRODUCT HIGHLIGHTS REVISION HISTORY SPECIFICATIONS I2C TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY CIRCUIT INFORMATION CONVERTER OPERATION ANALOG INPUT ADC TRANSFER FUNCTION TEMPERATURE SENSOR OPERATION TEMPERATURE SENSOR AVERAGING Temperature Value Format VDRIVE THE INTERNAL OR EXTERNAL REFERENCE RESET INTERNAL REGISTER STRUCTURE ADDRESS POINTER REGISTER COMMAND REGISTER (0x00) Sample Delay and Bit Trial Delay VOLTAGE CONVERSION RESULT REGISTER (0x01) Temperature Value Format TSENSE CONVERSION RESULT REGISTER (0x02) TSENSE AVERAGE RESULT REGISTER (0X03) LIMIT REGISTERS (0X04 TO 0X1E) DATAHIGH Register DATALOW Register HYSTERESIS REGISTER ALERT STATUS REGISTER A AND ALERT STATUS REGISTER B (0x1F AND 0x20) I2C INTERFACE SERIAL BUS ADDRESS BYTE GENERAL I2C TIMING WRITING TO THE AD7291 WRITING TWO BYTES OF DATA TO A 16-BIT REGISTER WRITING TO MULTIPLE REGISTERS READING DATA FROM THE AD7291 READING TWO BYTES OF DATA FROM A 16-BIT REGISTER MODES OF OPERATION COMMAND MODE AUTOCYCLE MODE OUTLINE DIMENSIONS ORDERING GUIDE