AD7781CRUZ Analog Devices Inc, AD7781CRUZ Datasheet
AD7781CRUZ
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AD7781CRUZ Summary of contents
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FEATURES Pin-programmable filter response Update rate 16.7 Hz Pin-programmable in-amp gain Pin-programmable power-down and reset Status function Internal clock oscillator Internal bridge power-down switch Current 115 μA typical (gain = 1) 330 μA typical (gain = 128) ...
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AD7781 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Timing Characteristics ................................................................ 5 Absolute Maximum Ratings ............................................................ 6 Thermal Resistance ...................................................................... 6 ESD ...
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SPECIFICATIONS REF DD Table 2. Parameter Min ADC CHANNEL Output Update Rate (f ) ADC 2 No Missing Codes 20 Resolution, Peak-to-Peak RMS Noise Integral Nonlinearity Offset ...
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AD7781 Parameter INTERNAL CLOCK Frequency 64 − 3% Duty Cycle LOGIC INPUTS 2 SCLK, FILTER, GAIN, PDRST Input Low Voltage, V INL Input High Voltage, V 1.8 INH 2.4 SCLK (Schmitt-Triggered Input) 2 Hysteresis Input Currents Input Capacitance LOGIC OUTPUT ...
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TIMING CHARACTERISTICS 5.25 V, GND = 0 V, Input Logic Input Logic Table 3. 1 Parameter Limit at T ...
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AD7781 ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 4. Parameter AV to GND GND DD Analog Input Voltage to GND Reference Input Voltage to GND Digital Input Voltage to GND Digital Output Voltage ...
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PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS SCLK 1 DOUT/RDY 2 NC AD7781 3 GAIN TOP VIEW 4 (Not to Scale) AIN(+) 5 AIN(–) 6 REFIN(+) CONNECT Figure 6. SOIC Pin Configuration Table 6. Pin Function Descriptions Pin ...
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AD7781 TYPICAL PERFORMANCE CHARACTERISTICS 524,294 524,293 524,292 524,291 524,290 524,289 524,288 524,287 524,286 0 200 400 600 SAMPLE Figure 8. C Grade Noise ( Update Rate = 16.7 Hz, Gain = 128) REF DD 500 400 300 ...
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SAMPLE Figure 14. Noise ( Update Rate = 10 Hz, Gain = 1) REF DD 800 600 400 200 0 524,274 524,275 CODE Figure 15. Noise Distribution Histogram (V ...
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AD7781 OUTPUT NOISE AND RESOLUTION Table 7 and Table 8 show the rms noise of the AD7781 for the two output data rates and gain settings when using and reference. These numbers are typical ...
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THEORY OF OPERATION The AD7781 is a low power ADC that incorporates a precision, 20-bit, Σ-Δ modulator; a PGA; and an on-chip digital filter intended for measuring wide dynamic range, low frequency signals. The part provides a complete front-end solution ...
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AD7781 POWER-DOWN/RESET (PDRST) The PDRST pin functions as a power-down pin and a reset pin. When PDRST is taken low, the AD7781 is powered down. The entire ADC is powered down (including the on-chip clock), the low-side power switch is ...
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DIGITAL INTERFACE The serial interface of the AD7781 consists of two signals: SCLK and DOUT/ RDY . SCLK is the serial clock input for the device, and data transfers occur with respect to the SCLK signal. The DOUT/ RDY pin ...
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AD7781 APPLICATIONS INFORMATION The AD7781 provides a low cost, high resolution analog-to- digital function. Because the analog-to-digital function is provided by a Σ-Δ architecture, the part is more immune to noisy environments, making it ideal for use in sensor measure- ...
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GROUNDING AND LAYOUT Because the analog input and reference input of the ADC are differential, most of the voltages in the analog modulator are common-mode voltages. The excellent common-mode reject- tion of the part removes common-mode noise on these inputs. ...
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... AD7781CRZ-REEL −40°C to +105°C 1 AD7781CRUZ −40°C to +105°C 1 AD7781CRUZ-REEL −40°C to +105° RoHS Compliant Part. ©2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 8.75 (0.3445) 8.55 (0.3366) ...