Datasheet AD7709 (Analog Devices) - 4

AD7709 SPECIFICATIONS1 (VDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, REFIN(+) = 2.5 V; REFIN(–) = GND; GND = 0 V; XTAL1/XTAL2 = 32.768 kHz Crystal; all specifications TMIN to TMAX, unless otherwise noted.) Parameter AD7709A, AD7709B Unit Test Conditions
ADC CHANNEL SPECIFICATION Output Update Rate 5.4 Hz min 0.732 ms Increments 105 Hz max ADC CHANNEL No Missing Codes2 16 Bits min 20 Hz Update Rate Resolution 13 Bits p-p ±20 mV Range, 20 Hz Update Rate 16 Bits p-p ±2.56 V Range, 20 Hz Update Rate Output Noise and Update Rates See Tables II to V 2 ¥ 1 024 . REFIN Integral Nonlinearity2 ±30 ppm of FSR max Typically 2 ppm FSR = GAIN Offset Error ±3 mV typ Offset Error Drift vs. Temperature ±10 nV/∞C typ Full-Scale Error3 ±0.75 LSB typ B Grade, VDD = 4 V ±0.2 % of FS typ A Grade Gain Drift vs. Temperature ±0.5 ppm/∞C typ Power Supply Rejection (PSR) 85 dB typ Input Range = ± 2.56 V 100 dB typ on ± 20 mV Range ANALOG INPUTS ±1 024 . ¥ REFIN Differential Input Voltage Ranges GAIN V nom REFIN = REFIN(+) – REFIN(–) GAIN = 1 to 128 ADC Range Matching ±2 mV typ Input Voltage = 19 mV on All Ranges Absolute AIN1–AIN4 Voltage Limits2 GND + 100 mV V min VDD – 100 mV V max AIN1–AIN4 Analog Input Current DC Input Current2 ±1 nA max DC Input Current Drift ±5 pA /∞C typ Absolute AINCOM Voltage Limits2 GND – 30 mV V min VDD + 30 mV V max AINCOM Analog Input Current Pseudo-Differential Mode of Operation DC Input Current ±125 nA/V typ Input Current Varies with Input Range DC Input Current Drift ±2 pA/V/∞C typ Normal-Mode Rejection2, 4 @ 50 Hz 100 dB min 50 Hz ± 1 Hz, 16.65 Hz Update Rate, SF = 82 @ 60 Hz 100 dB min 60 Hz ± 1 Hz, 20 Hz Update Rate, SF = 68 Common-Mode Rejection @ DC 100 dB typ Input Range = ± 2.56 V, AIN = 1 V 110 dB typ on ± 20 mV Range @ 50 Hz2 100 dB min 50 Hz ± 1 Hz, Range = ± 2.56 V, AIN = 1 V @ 60 Hz2 100 dB min 60 Hz ± 1 Hz, Range = ± 2.56 V, AIN = 1 V REFERENCE INPUTS (REFIN1 and REFIN2) REFIN Voltage 2.5 V nom REFIN = REFIN(+) – REFIN(–) REFIN Voltage Range2 1 V min VDD V max Absolute REFIN Voltage Limits2 GND – 30 mV V min VDD + 30 mV V max Average Reference Input Current 0.5 mA/V typ Average Reference Input Current Drift ±0.01 nA/V/∞C typ Normal-Mode Rejection2, 4 @ 50 Hz 100 dB min 50 Hz ± 1 Hz, SF = 82 @ 60 Hz 100 dB min 60 Hz ± 1 Hz, SF = 68 Common-Mode Rejection @ DC 110 dB typ Input Range = ± 2.56 V, AIN = 1 V @ 50 Hz 110 dB typ 50 Hz ± 1 Hz, Range = 2.56 V, AIN = 1 V @ 60 Hz 110 dB typ 60 Hz ± 1 Hz, Range = 2.56 V, AIN = 1 V See Notes on page 5. REV. A –3– Document Outline FEATURES INTERFACE POWER ON-CHIP FUNCTIONS APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS SPECIFICATIONS TIMING CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDERING GUIDE PIN FUNCTION DESCRIPTIONS Typical Performance Characteristics ADC CIRCUIT INFORMATION Overview Sigma-Delta ADC NOISE PERFORMANCE ON-CHIP REGISTERS Communications Register (A1, A0 = 0, 0) Status Register (A1, A0 = 0, 0; Power-On-Reset = 00H) Configuration Register (A1, A0 = 0, 1; Power-On-Reset = 000007H) Filter Register (A1, A0 = 1, 0; Power-On-Reset = 45h) ADC Data Result Register (A1, A0 = 1, 1; Power-On-Reset = 0000h CONFIGURING THE AD7709 DIGITAL INTERFACE MICROCOMPUTER/MICROPROCESSOR INTERFACING AD7709-to-68HC11 Interface AD7709-to-8051 Interface AD7709-to-ADSP-2103/ADSP-2105 Interface CIRCUIT DESCRIPTION Analog Input Channels Programmable Gain Amplifier Bipolar/Unipolar Configuration Data Output Coding Excitation Currents Crystal Oscillator Reference Input Reset Input Power-Down Mode Grounding and Layout APPLICATIONS Pressure Measurement Temperature Measurement 3-Wire RTD Configurations Smart Transmitters OUTLINE DIMENSIONS Revision History