Datasheet AD7705, AD7706 (Analog Devices) - 4

AD7705/AD7706 PRODUCT HIGHLIGHTS
1. The AD7705/AD7706 devices consume less than 1 mW at 3. The AD7705/AD7706 are ideal for microcontroller or DSP 3 V supplies and 1 MHz master clock, making them ideal processor applications with a 3-wire serial interface, for use in low power systems. Standby current is less than 8 reducing the number of interconnect lines and reducing μA. the number of opto-couplers required in isolated systems. 2. The programmable gain input allows the AD7705/AD7706 4. The parts feature excellent static performance to accept input signals directly from a strain gage or specifications with 16 bits, no missing codes, ±0.003% transducer, removing a considerable amount of signal accuracy, and low rms noise (<600 nV). Endpoint errors conditioning. and the effects of temperature drift are eliminated by on- chip calibration options, which remove zero-scale and full- scale errors. Rev. C | Page 4 of 44 Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM REVISION HISTORY PRODUCT HIGHLIGHTS SPECIFICATIONS TIMING CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS OUTPUT NOISE (5 V OPERATION) OUTPUT NOISE (3 V OPERATION) TYPICAL PERFORMANCE CHARACTERISTICS ON-CHIP REGISTERS COMMUNICATION REGISTER (RS2, RS1, RS0 = 0, 0, 0) SETUP REGISTER (RS2, RS1, RS0 = 0, 0, 1); POWER-ON/RESET STATUS: 01 HEXADECIMAL CLOCK REGISTER (RS2, RS1, RS0 = 0, 1, 0); POWER-ON/RESET STATUS: 05 HEXADECIMAL DATA REGISTER (RS2, RS1, RS0 = 0, 1, 1) TEST REGISTER (RS2, RS1, RS0 = 1, 0, 0); POWER-ON/RESET STATUS: 00 HEXADECIMAL ZERO-SCALE CALIBRATION REGISTER (RS2, RS1, RS0 = 1, 1, 0); POWER-ON/RESET STATUS: 1F4000 HEXADECIMAL FULL-SCALE CALIBRATION REGISTER (RS2, RS1, RS0 = 1, 1, 1); POWER-ON/RESET STATUS: 5761AB HEXADECIMAL Calibration Sequences CIRCUIT DESCRIPTION ANALOG INPUT Ranges Sample Rate BIPOLAR/UNIPOLAR INPUT REFERENCE INPUT DIGITAL FILTERING Filter Characteristics Postfiltering ANALOG FILTERING CALIBRATION Self-Calibration System Calibration Span and Offset Limits Power-Up and Calibration THEORY OF OPERATION CLOCKING AND OSCILLATOR CIRCUIT SYSTEM SYNCHRONIZATION RESET INPUT STANDBY MODE ACCURACY DRIFT CONSIDERATIONS POWER SUPPLIES SUPPLY CURRENT GROUNDING AND LAYOUT EVALUATING THE PERFORMANCE DIGITAL INTERFACE CONFIGURING THE AD7705/AD7706 MICROCOMPUTER/MICROPROCESSOR INTERFACING AD7705/AD7706-to-68HC11 Interface AD7705/AD7706-to-8051 Interface AD7705/AD7706-to-ADSP-2103/ADSP-2105 Interface CODE FOR SETTING UP THE AD7705/AD7706 C Code for Interfacing AD7705 to 68HC11 APPLICATIONS PRESSURE MEASUREMENT TEMPERATURE MEASUREMENT SMART TRANSMITTERS BATTERY MONITORING OUTLINE DIMENSIONS ORDERING GUIDE