link to page 12 link to page 14 AD7291Data SheetParameterMinTypMaxUnit1Test Conditions/Comments Floating State Leakage Current ±0.01 ±1 µA Floating State Output Capacitance3 8 pF TEMPERATURE SENSOR—INTERNAL Operating Range −40 +125 °C Accuracy ±1 ±2 °C TA = −40°C to +85°C ±1 ±3 °C TA = 85°C to 125°C Resolution 0.25 °C LSB size CONVERSION RATE Conversion Time 3.2 μs Autocycle Update Rate6 50 μs Throughput Rate 22.22 kSPS fSCL = 400 kHz POWER REQUIREMENTS Digital inputs = 0 V or VDRIVE VDD 2.8 3 3.6 V VDRIVE 1.65 3 3.6 V I 7, 8 TOTAL Normal Mode (Operational) 2.9 3.5 mA Normal Mode (Static) 2.9 3.3 mA Full Power-Down Mode 0.3 1.6 μA TA = −40°C to +25°C 1.6 4.5 μA TA = >25°C to 85°C 4.9 12 μA TA = >85°C to 125°C Power Dissipation8 Normal Mode (Operational) 8.7 10.5 mW VDD = 3 V, VDRIVE = 3 V 10.4 12.6 mW Normal Mode (Static) 10.4 11.9 mW Full Power-Down Mode 1.1 5.8 µW TA = −40°C to +25°C 5.8 16.2 µW TA = >25°C to 85°C 17.6 43.2 µW TA = >85°C to 125°C 1 All specifications expressed in decibels are referred to full-scale input, FSR, and tested with an input signal at 0.5 dB below ful scale, unless otherwise specified. 2 See the Terminology section. 3 Sample tested during initial release to ensure compliance. 4 Refers to Pin VREF specified for 25oC. 5 A correction factor can be required on the temperature sensor results when using an external VREF (see the Temperature Sensor Averaging section). 6 Sampled during initial release to ensure compliance; not subject to production testing. 7 ITOTAL is the total current flowing in VDD and VDRIVE. 8 ITOTAL and power dissipation are specified with VDD = VDRIVE = 3.6 V, unless otherwise noted. Rev. C | Page 4 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