AD7745ARUZ Analog Devices Inc, AD7745ARUZ Datasheet
AD7745ARUZ
Specifications of AD7745ARUZ
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AD7745ARUZ Summary of contents
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FEATURES Capacitance-to-digital converter New standard in single chip solutions Interfaces to single or differential floating sensors Resolution down (that is ENOB) Accuracy Linearity: 0.01% Common-mode (not changing) capacitance ...
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AD7745/AD7746 TABLE OF CONTENTS Specifications..................................................................................... 3 Timing Specifications....................................................................... 5 Absolute Maximum Ratings............................................................ 6 Pin Configurations and Function Descriptions ........................... 7 Typical Performance Characteristics ............................................. 8 Output Noise and Resolution Specifications .............................. 11 Serial Interface ................................................................................ 12 Read Operation........................................................................... 12 Write ...
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SPECIFICATIONS 5.25 V; GND = 0 V; EXC = 32 kHz; EXC = ±V DD Table 1. Parameter CAPACITIVE INPUT Conversion Input Range 2 Integral Nonlinearity (INL ...
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AD7745/AD7746 Parameter Full-Scale Drift vs. Temperature Average VIN Input Current Analog VIN Input Current Drift Power Supply Rejection Power Supply Rejection Normal Mode Rejection Common-Mode Rejection INTERNAL VOLTAGE REFERENCE Voltage Drift vs. Temperature EXTERNAL VOLTAGE REFERENCE INPUT 2 Differential REFIN ...
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TIMING SPECIFICATIONS 5.25 V; GND = 0 V; Input Logic Input Logic Table 2. Parameter 1, 2 SERIAL INTERFACE SCL Frequency ...
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AD7745/AD7746 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter Positive Supply Voltage V to GND DD Voltage on any Input or Output Pin to GND ESD Rating (ESD Association Human Body Model, S5.1) Operating Temperature ...
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PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS SCL RDY EXCA 3 14 AD7745 EXCB 4 13 TOP VIEW REFIN(+) 5 (Not to Scale) 12 REFIN(– CIN1(– CIN1(+) CONNECT Figure ...
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AD7745/AD7746 TYPICAL PERFORMANCE CHARACTERISTICS 100 –5 –4 –3 –2 – INPUT CAPACITANCE (pF) Figure 6. Capacitance Input Integral Nonlinearity the Same Configuration as in Figure 31 DD 2000 1000 ...
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CIN LEAKAGE TO GND (nA) Figure 12. Capacitance Input Error vs. Leakage Current to GND, CIN(+) to EXC = ...
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AD7745/AD7746 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –50 – TEMPERATURE (°C) Figure 18. Internal Temperature Sensor Error vs. Temperature 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 –2.5 –3.0 –50 – TEMPERATURE ...
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OUTPUT NOISE AND RESOLUTION SPECIFICATIONS The AD7745/AD7746 resolution is limited by noise. The noise performance varies with the selected conversion time. Table 5 shows typical noise performance and resolution for the capacitive channel. These numbers were generated from 1000 data ...
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AD7745/AD7746 SERIAL INTERFACE 2 The AD7745/AD7746 supports an I C-compatible 2-wire serial 2 interface. The two wires on the I C bus are called SCL (clock) and SDA (data). These two wires carry all addressing, control, and data information one ...
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If a repeated start condition is encountered after the address pointer byte, all peripherals connected to the bus respond exactly as outlined above for a start condition, that is, a repeated start condition is treated the same as a start ...
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AD7745/AD7746 REGISTER DESCRIPTIONS The master can write to or read from all of the AD7745/ AD7746 registers except the address pointer register, which is a write-only register. The address pointer register determines which register the next read or write operation ...
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STATUS REGISTER Address Pointer 0x00, Read Only, Default Value 0x07 This register indicates the status of the converter. The status register can be read via the 2-wire serial interface to query a finished conversion. Table 9. Status Register Bit Map ...
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AD7745/AD7746 CAP SET-UP REGISTER Address Pointer 0x07, Default Value 0x00 Capacitive channel setup. Table 11. CAP Set-Up Register Bit Map Bit Bit 7 Mnemonic CAPEN Default 0 Table 12. Bit Mnemonic Description 7 CAPEN CAPEN = 1 enables capacitive channel ...
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EXC SET-UP REGISTER Address Pointer 0x09, Default Value 0x03 Capacitive channel excitation setup. Table 15. EXC Set-Up Bit Map Bit Bit 7 Mnemonic CLKCTRL Default 0 Table 16. Bit Mnemonic Description 7 CLKCTRL The CLKCTRL bit should be set to ...
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AD7745/AD7746 CONFIGURATION REGISTER Address Pointer 0x0A, Default Value 0xA0 Converter update rate and mode of operation setup. Table 17. Configuration Register Bit Map Bit Bit 7 Mnemonic VTF1 Default 0 Table 18. Bit Mnemonic Description 7 VTF1 Voltage/temperature channel digital ...
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CAP DAC A REGISTER Address Pointer 0x0B, Default Value 0x00 Capacitive DAC setup. Table 19. Cap DAC A Register Bit Map Bit Bit 7 Mnemonic DACAENA Default 0 Table 20. Bit Mnemonic Description 7 DACAENA DACAENA = 1 connects capacitive ...
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AD7745/AD7746 CIRCUIT DESCRIPTION TEMP CLOCK SENSOR GENERATOR VIN(+) VIN(–) MUX 24-BIT Σ-∆ CIN1(+) MODULATOR CIN1(–) CAP DAC CAP DAC EXCA EXCITATION EXCB REFIN(+) REFIN(–) Figure 26. AD7745 Block Diagram OVERVIEW The AD7745/AD7746 core is a high precision converter con- sisting ...
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CAPDAC The AD7745/AD7746 CDC full-scale input range is ±4.096 pF. For simplicity of calculation, however, the following text and diagrams use ±4 pF. The part can accept a higher capacitance on the input and the common-mode or offset (not-changing component) ...
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AD7745/AD7746 CAPDAC(+) 17pF CIN(+) CAPDIFF = 1 CIN(–) CAPDAC(– 17pF 15 ... 19pF 15 ... 19pF (17 ± 2pF) (17 ± 2pF) EXC Figure 34. Using CAPDAC in Differential Mode CAPDAC(+) 17pF CIN(+) ± 4pF CAPDIFF ...
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PARASITIC SERIAL RESISTANCE R S1 CIN EXC Figure 39. Parasitic Serial Resistance The AD7745/AD7746 CDC result is affected by a resistance in series with the measured capacitance. The total serial resistance, which refers ...
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AD7745/AD7746 If the capacitive sensor can be considered the same temperature as the AD7745/AD7746 chip, the internal temperature sensor can be used as a system temperature sensor. That means the complete system temperature drift compensation can be ...
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... OUTLINE DIMENSIONS 0.15 0.05 ORDERING GUIDE Model Temperature Range AD7745ARUZ 1 –40°C to +125°C 1 AD7745ARUZ-REEL –40°C to +125°C 1 AD7745ARUZ-REEL7 –40°C to +125°C 1 AD7746ARUZ –40°C to +125°C 1 AD7746ARUZ-REEL –40°C to +125°C 1 AD7746ARUZ-REEL7 –40°C to +125°C EVAL-AD7746EB Pb-free part. ...
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AD7745/AD7746 NOTES Rev Page ...
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NOTES Rev Page AD7745/AD7746 ...
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AD7745/AD7746 NOTES 2 Purchase of licensed I C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I 2 Patent Rights to use these components ...