ABSOLUTE MAXIMUM RATINGS* Plastic DIP Package, Power Dissipation .. 450 mW (TA = +25°C unless otherwise noted) θJA Thermal Impedance ... 105°C/W AVDD to AGND .. –0.3 V to +7 V Lead Temperature (Soldering, 10 sec) .. +260°C AVDD to DGND .. –0.3 V to +7 V TSSOP Package, Power Dissipation .. 450 mW DVDD to AGND .. –0.3 V to +7 V θJA Thermal Impedance ... 128°C/W DVDD to DGND .. –0.3 V to +7 V Lead Temperature, Soldering AGND to DGND .. –5 V to +0.3 V Vapor Phase (60 sec) .. +215°C AVDD to DVDD ... –2 V to +5 V Infrared (15 sec) ... +220°C Analog Input Voltage to AGND ... –0.3 V to AVDD + 0.3 V SOIC Package, Power Dissipation .. 450 mW Reference Input Voltage to AGND ... –0.3 V to AVDD + 0.3 V θ AIN/REF IN Current (Indefinite) .. 30 mA JA Thermal Impedance ... 75°C/W Lead Temperature, Soldering Digital Input Voltage to DGND .. –0.3 V to DVDD + 0.3 V Digital Output Voltage to DGND ... –0.3 V to DV Vapor Phase (60 sec) .. +215°C DD + 0.3 V Output Voltage (D0, D1) to DGND .. –0.3 V to AV Infrared (15 sec) .. +220°C DD + 0.3 V *Stresses above those listed under Absolute Maximum Ratings may cause Operating Temperature Range permanent damage to the device. This is a stress rating only; functional Industrial (B Version) ... –40°C to +85°C operation of the device at these or any other conditions above those listed in the Storage Temperature Range .. –65°C to +150°C operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Junction Temperature ... +150°C ORDERING GUIDEModel (Z = RoHS)Temperature RangePackage DescriptionPackage OptionRoHS Compliant AD7731BN −40°C to +85°C 24-Lead PDIP N-24-1 No AD7731BNZ −40°C to +85°C 24-Lead PDIP N-24-1 Yes AD7731BR −40°C to +85°C 24-Lead SOIC_W RW-24 No AD7731BR-REEL −40°C to +85°C 24-Lead SOIC_W RW-24 No AD7731BR-REEL7 −40°C to +85°C 24-Lead SOIC_W RW-24 No AD7731BRZ −40°C to +85°C 24-Lead SOIC_W RW-24 Yes AD7731BRZ-REEL −40°C to +85°C 24-Lead SOIC_W RW-24 Yes AD7731BRZ-REEL7 −40°C to +85°C 24-Lead SOIC_W RW-24 Yes AD7731BRU −40°C to +85°C 24-Lead TSSOP RU-24 No AD7731BRU-REEL −40°C to +85°C 24-Lead TSSOP RU-24 No AD7731BRU-REEL7 −40°C to +85°C 24-Lead TSSOP RU-24 No AD7731BRUZ −40°C to +85°C 24-Lead TSSOP RU-24 Yes AD7731BRUZ-REEL −40°C to +85°C 24-Lead TSSOP RU-24 Yes AD7731BRUZ-REEL7 −40°C to +85°C 24-Lead TSSOP RU-24 Yes EVAL-AD7731EBZ Evaluation Board Yes ISINK (800µA AT DVDD = +5V100µA AT DVDD = +3V)TO OUTPUT+1.6VPIN50pFISOURCE (200µA AT DVDD = +5V100µA AT DVDD = +3V) Figure 1. Load Circuit for Access Time and Bus Relinquish Time ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. REV. A A ‐5‐ Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM AD7731-SPECIFICATIONS TIMING CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS Ordering Guide ESD Caution PIN CONFIGURATION Pin Function Descriptions TERMINOLOGY OUTPUT NOISE AND RESOLUTION SPECIFICATION Output Noise (CHP = 0, SKIP= 1) Output Noise (CHP = 1, SKIP = 0) ON-CHIP REGISTERS Communications Register (RS2-RS0 = 0, 0, 0) Status Register (RS2-RS0 = 0, 0, 0); Power-On/Reset Status: CX Hex Data Register (RS2-RS0 = 0, 0, 1); Power On/Reset Status: 000000 Hex Mode Register (RS2-RS0 = 0, 1, 0); Power-On/Reset Status: 0174 Hex Filter Register (RS2-RS0 = 0, 1, 1); Power-On/Reset Status: 2002 Hex Offset Calibration Register (RS2-RS0 = 1, 0, 1) Gain Calibration Register (RS2-RS0 = 1, 1, 0) Test Register (RS2-RS0 = 1, 1, 1); Power On/Reset Status: 000000 Hex READING FROM AND WRITING TO THE ON-CHIP REGISTERS CALIBRATION OPERATION SUMMARY CIRCUIT DESCRIPTION ANALOG INPUT Analog Input Channels Buffered Inputs Analog Input Ranges Programmable Gain Amplifier Bipolar/Unipolar Inputs Burnout Currents REFERENCE INPUT Reference Detect SIGMA-DELTA MODULATOR DIGITAL FILTERING Filter Architecture First State Filter/SKIP Mode Enabled (SKIP =1) Nonchop Mode (SKIP =1, CHP = 0) Chop Mode (SKIP = 1, CHP =1) Second Stage Filter Normal FIR Operation (SKIP = 0) Chop Mode (SKIP = 0, CHP =1) Nonchop Mode (SKIP = 1, CHP = 0) FASTStep Mode (SKIP = 0, FAST = 1) CALIBRATION Internal Zero-Scale Calibration Internal Full-Scale Calibration System Zero-Scale Calibration System Full-Scale Calibration Span and Offset Limits Power-Up and Calibration Drift Considerations USING THE AD7731 Clocking and Oscillator Circuit System Synchronization Single-Shot Conversions Reset Input Standby Mode Digital Outputs POWER SUPPLIES Grounding and Layout Evaluting the AD7731 Performance SERIAL INTERFACE Write Operation Read Operation CONFIGURING THE AD7731 MICROCOMPUTER/MICROPROCESSOR INTERFACING AD7731 to 68HC11 Interface AD7731 to 8051 Interface AD7731 to ADSP-2103/ADSP-2105 Interface APPLICATIONS Data Acquisition Programmable Logic Controllers Pressure Measurement Temperature Measurement Bipolar Input Signals PAGE INDEX TABLE INDEX OUTLINE DIMENSIONS