Datasheet AD7817, AD7818 (Analog Devices) - 3

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Data Sheet AD7817/AD7818 SPECIFICATIONS
VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V, unless otherwise noted. The AD7817 temperature sensor is specified with an external 2.5 V reference, and the AD7818 temperature sensor is specified with an on-chip reference. For VDD = 2.7 V, TA = 85°C maximum and temperature sensor measurement error = ±3°C.
Table 1. Parameter A Version1 B Version1 S Version1 U nit Test Conditions/Comments
DYNAMIC PERFORMANCE (AD7817 ONLY) Sample rate = 100 kSPS, any channel, fIN = 20 kHz Signal-to-(Noise + Distortion) Ratio2 58 58 58 dB min Total Harmonic Distortion2 –65 −65 −65 dB max −75 dB typical Peak Harmonic or Spurious Noise2 –65 −65 −65 dB max −75 dB typical Intermodulation Distortion2 fa =19.9 kHz, fb = 20.1 kHz Second-Order Terms –67 −67 −67 dB typ Third-Order Terms –67 −67 −67 dB typ Channel-to-Channel Isolation2 –80 −80 −80 dB typ fIN = 20 kHz DC ACCURACY (AD7817 ONLY) Any channel Resolution 10 10 10 Bits Minimum Resolution for Which No 10 10 10 Missing Codes are Guaranteed Relative Accuracy2 ±1 ±1 ±1 LSB max Differential Nonlinearity2 ±1 ±1 ±1 LSB max Gain Error2 ±2 ±2 ±2 LSB max External reference ±10 ±10 +20/−10 LSB max Internal reference Gain Error Match2 ±1/2 ±1/2 ±1/2 LSB max Offset Error2 ±2 ±2 ±2 LSB max Offset Error Match ±1/2 ±1/2 ±1/2 LSB max TEMPERATURE SENSOR (AD7817 ONLY) Measurement Error External reference VREF = 2.5 V Ambient Temperature 25°C ±2 ±1 ±2 °C max TMIN to TMAX ±3 ±2 ±3 °C max Measurement Error On-chip reference Ambient Temperature 25°C ±2.25 ±2.25 ±2.25 °C max TMIN to TMAX ±3 ±3 ±6 °C max Temperature Resolution 1/4 1/4 1/4 °C/LSB REFERENCE INPUT (AD7817 ONLY)3, 4 REFIN Input Voltage Range3 2.625 2.625 2.625 V max 2.5 V + 5% 2.375 2.375 2.375 V min 2.5 V − 5% Input Impedance 40 40 40 kΩ min Input Capacitance 10 10 10 pF max ON-CHIP REFERENCE (AD7817 ONLY)5 Nominal 2.5 V Temperature Coefficient3 80 80 150 ppm/°C typ CONVERSION RATE (AD7817 ONLY) Track-and-Hold Acquisition Time4 400 400 400 ns max Source Impedance < 10 Ω Conversion Time Temperature Sensor 27 27 27 μs max Channel 1 to Channel 4 9 9 9 μs max Rev. E | Page 3 of 20 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAMS GENERAL DESCRIPTION PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TERMINOLOGY CONTROL BYTE Address Register Overtemperature Register CIRCUIT INFORMATION CONVERTER DETAILS TYPICAL CONNECTION DIAGRAM ANALOG INPUTS Analog Input DC Acquisition Time AC Acquisition Time ON-CHIP REFERENCE ADC TRANSFER FUNCTION TEMPERATURE MEASUREMENT TEMPERATURE MEASUREMENT ERROR DUE TO REFERENCE ERROR SELF-HEATING CONSIDERATIONS OPERATING MODES Mode 1 Mode 2 POWER vs. THROUGHPUT AD7817 SERIAL INTERFACE Read Operation Write Operation Simplifying the Serial Interface AD7818 SERIAL INTERFACE MODE Read Operation Write Operation OUTLINE DIMENSIONS ORDERING GUIDE